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  • 1.
    Alaniz, Monica
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Belyayev, Serhiy
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Bergman, David
    Casselbrant, Gustav
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Honeth, Mark
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Huang, Jiangwei
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Ivchenko, Nickolay
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Laukkanen, Mikko
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Michelsen, Jacob
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Pronenko, Vira
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Paulson, Malin
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Schlick, Georg
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Valle, Mario
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    The SQUID sounding rocket experiment2011In: Proceedings of the 20th ESA Symposium on European Rocket and Balloon Programmes and Related Research, European Space Agency, 2011, 159-166 p.Conference paper (Refereed)
    Abstract [en]

    The objective of the SQUID project is to develop and in flight verify a miniature version of a wire boom deployment mechanism to be used for electric field measurements in the ionosphere. In February 2011 a small ejectable payload, built by a team of students from The Royal Institute of Technology (KTH), was launched from Esrange on-board the REXUS-10 sounding rocket. The payload separated from the rocket, deployed and retracted the wire booms, landed with a parachute and was subsequently recovered. Here the design of the experiment and post fight analysis are presented.

  • 2. Balmer, G.
    et al.
    Berquand, A.
    Company-Vallet, E.
    Granberg, V.
    Grigore, V.
    Ivchenko, Nickolay
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Kevorkov, R.
    Lundkvist, E.
    Olentsenko, Georgi
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Pacheco-Labrador, J.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Yuan, Yunxia
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    ISAAC: A REXUS STUDENT EXPERIMENT TO DEMONSTRATE AN EJECTION SYSTEM WITH PREDEFINED DIRECTION2015In: EUROPEAN ROCKET AND BALLOON: PROGRAMMES AND RELATED RESEARCH, 2015, 235-242 p.Conference paper (Refereed)
    Abstract [en]

    ISAAC - Infrared Spectroscopy to Analyse the middle Atmosphere Composition was a student experiment launched from SSC's Esrange Space Centre, Sweden, on 29th May 2014, on board the sounding rocket REXUS 15 in the frame of the REXUS/BEXUS programme. The main focus of the experiment was to implement an ejection system for two large Free Falling Units (FFUs) (240 mm x 80 mm) to be ejected from a spinning rocket into a predefined direction. The system design relied on a spring-based ejection system. Sun and angular rate sensors were used to control and time the ejection. The flight data includes telemetry from the Rocket Mounted Unit (RMU), received and saved during flight, as well as video footage from the GoPro camera mounted inside the RMU and recovered after the flight. The FFUs' direction, speed and spin frequency as well as the rocket spin frequency were determined by analyzing the video footage. The FFU-Rocket-Sun angles were 64.3 degrees and 104.3 degrees, within the required margins of 90 degrees +/- 45 degrees. The FFU speeds were 3.98 m/s and 3.74 m/s, lower than the expected 5 +/- 1 m/s. The FFUs' spin frequencies were 1.38 Hz and 1.60 Hz, approximately half the rocket's spin frequency. The rocket spin rate slightly changed from 3.163 Hz before the ejection to 3.117 Hz after the ejection of the two FFUs. The angular rate, sun sensor data and temperature on the inside of the rocket module skin were also recorded. The experiment design and results of the data analysis are presented in this paper.

  • 3.
    Bergström, Rasmus
    et al.
    KTH.
    Crimella, Matteo
    KTH.
    Ivchenko, Nickolay
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Karlsson, Alexander
    KTH.
    Lindberg, Hannah
    KTH.
    Persson, Linnea
    KTH.
    Schlatter, Nicola
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Westerlund, Simon
    KTH.
    SCATTERING OF RADAR WAVES ON AEROSOLS IN PLASMAS2015In: EUROPEAN ROCKET AND BALLOON: PROGRAMMES AND RELATED RESEARCH, 2015, 87-94 p.Conference paper (Refereed)
    Abstract [en]

    To study the physical mechanisms of phenomena such as polar mesospheric summer echoes, the SCRAP (Scattering of Radar waves on Aerosols in Plasmas) experiment aimed to validate theories on density fluctuations in dusty plasmas. The SCRAP team developed two identical free falling units (FFUs) designed to create a cloud of copper particles once they eject from the REXUS17 sounding rocket 124 seconds after launch. By using the EISCAT incoherent scatter radar system to observe the cloud, the SCRAP experiment proposed to relate theoretical predictions to a controlled object. The SCRAP experiment was launched from ESRANGE on March the 17th 2015. The FFUs GPS signal was lost during launch and the units were therefore not found. Moreover, no backscattering from the copper cloud was observed by the radar.

  • 4.
    Bordogna, Marco Tito
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Fidjeland, Leo
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Fjällid, Markus
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Galrinho, Miguel
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Haponen, Anders
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Hou, Anton
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Ivchenko, Nickolay
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Kristmundsson, Darri
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Lárusdóttir, Ólafía
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Lejon, Marcus
    KTH, School of Engineering Sciences (SCI), Mechanics.
    Lindh, Marcus
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Lozano, Emilio
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Magnusson, Patrick
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Myleus, Andreas
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Oakes, Ben D.
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    MUSCAT experiment: active free falling units for in situ measurements of temperature and density in the middle atmosphere2013In: European Space Agency: (Special Publication) ESA SP / [ed] L. Ouwehand, ESTEC, Noordwijk, The Netherlands: ESA Communications , 2013, 575-582 p.Conference paper (Other academic)
    Abstract [en]

    The main scientific objective of the MUSCAT Experimentis to develop a technique to reconstruct temperatures and density profiles in the middle atmosphere using active spherical probes. The MUSCAT experiment was launched on May 9, 2013 on the REXUS-13 sounding rocket from Esrange, in northern Sweden. The experiment ejected four probes that collected raw GPS signal. The experiment design and preliminary results are presented here.

  • 5.
    Dalil Safaei, Seif
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Eriksson, Anders
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Optimum pre-stress design for frequency requirement of tensegrity structures2011In: Proceeding of 10th World Congress on Computational Mechanics, 2011Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    Structures composed of tension and compression elements in equilibrium are denoted tensegrity structures. Stability of tensegrity structures is achieved through introducing initial member forces (pre-stress). The pre-stress design can be seen consisting of three different stages: (i) finding the bases of possible pre-stress states, (ii) finding admissible distributions considering unilateral properties of the elements and stability of the structure, (iii) finding the optimum pre-stress pattern for certain magnitude from compatible pre-stress states. So far, no research has been carried out to connect the three steps, i.e. finding a suitable pre-stress pattern which also considers mechanical properties of the highly pre-stressed structure e.g. its natural frequencies. This paper aims at finding an optimum pre-stress pattern and level of pre-stress for the maximum frequency. The pre-stress problem is on a linear static level where no slackening is allowed. An optimization is performed to find the optimum pre-stress pattern fromthe self-stress modes obtained by a singular value decomposition (SVD) of the equilibrium matrix. The objective function is the first natural frequency of the structure. Finite element analysis is employed for the linear analysis of the structure and a genetic algorithm for optimization i.e., a non-gradient method. The example considered is a double layer tensegrity grid consisting of 29 independent self-stress states. The method is applicable to complex asymmetric three-dimensional structures. The new aspect of this work is a link between the SVD analysis, finite element analysis and genetic algorithm.

  • 6.
    Dalilsafaei, Seif
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Eriksson, Anders
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Micheletti, A.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Parametric study of various tensegrity modules asbuilding blocks for slender boomsArticle in journal (Other academic)
  • 7.
    Dalilsafaei, Seif
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Eriksson, Anders
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Application of flexibility analysis for design of tensegrity structures2011In: Proceeding of the 4th Structural Engineering World Congress, 2011Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    Tensegrity structures have been the subject of research for many years, but very few of them have been built. One major disadvantage of tensegrities compared to typical trusses is their stiffness, which can be significantly reduced when a cable goes slack. This paper aims to introduce a method for stiffness characterization of tensegrity structures for the following purposes: (i) comparison of the stiffness of tensegrity structures with other truss structures, (ii) comparison of the stiffness of different form-found geometries, (iii) finding the most flexible nodes and the principal flexibility directions and (iv) finding stiffness effects of different pre-stress levels and patterns. The method is based on the flexibility analysis of tensegrity structures and the finite element method is used for the non-linear static analysis of the structure to obtain the flexibility figures which visualize the flexibility for different plane and spatial truss and slender boom tensegrity structures.

     

  • 8.
    Dalilsafaei, Seif
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Eriksson, Anders
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Flexibility-based pre-stress design of tensegrity structuresManuscript (preprint) (Other academic)
    Abstract [en]

    Tensegritiy structures have been subjects of research for many years, but very few of them have been built. One major disadvantage of tensegrities compare to regular truss structures is their low stiffness. This papers aims to have a new look at the stiffness problem of tensegrity structures. Here, it is assumed that the form-finding step has been completed and the axial stiffness of the elements is known. We introduce a tool for stiffness characterization of a given tensegrity structure for different pre-stress magnitudes. Since the pre-stress has a critical influence on the stability of the structure with a role to prevent or postpone slackening, the magnitude of pre-stress of the structure exposed to large external loads and disturbances are found. Finite elements are utilized in the solution for the non-linear static analysis. The method is based on geometrical interpretation of flexibility of unconstrained nodes. Suggested concept, flexibility analysis, shows promising properties in finding flexible nodes, weak directions of structure, detection of cable elements with higher risk of going slack and better knowledge of influence of various external loads. The authors believe results of this research could help the researchers and designer of better understanding the behavior of tensegrity structures.

     

  • 9.
    Dalilsafaei, Seif
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Eriksson, Anders
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Improving bending stiffness of tensegrity booms2012In: International Journal of Space Structures, ISSN 0956-0599, Vol. 27, no 2-3, 117-129 p.Article in journal (Refereed)
    Abstract [en]

    There is a high interest in employing lightweight, low-cost, deployable structures for space missions. Utilization of tensegrity structures in space application is limited, due to their low stiffness, while a number of high stiffness-to-mass truss booms have been launched. This paper aims to describe and improve the bending stiffness of tensegrity booms. Tensegrity booms of Snelson and triangular prism type are selected for the study. These structures are excellent samples of class 1 tensegrities, with a single state of self-stress and one mechanism, and class 2 tensegrities, with multiple states of self-stress and mechanisms. The stiffness modification procedure includes three steps: (Step 1) developing a strategy for a fair comparison of tensegrity booms with a high performance truss boom. A genetic algorithm is employed to find the optimum cross-section areas of the boom elements. Sources of low stiffness of tensegrities are discussed. (Step 2) an effort is made to find the optimum placement of actuators for improving the stiffness of the tensegrity booms. (Step 3) a genetic algorithm is utilized to calculate their optimum actuation. All three stages have been performed based on a link between non-linear finite element analysis and a genetic algorithm. The genetic algorithm shows high accuracy of searching non-structural space, and also dealing with above steps. Results indicate that the stiffness of tensegrity booms is highly improved by activating the structures.

  • 10.
    Dalilsafaei, Seif
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Eriksson, Anders
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Sensitivity analysis of tensegrity booms due to member loss2011In: Proceedings NSCM-24, 2011Conference paper (Other academic)
  • 11.
    Dalilsafaei, Seif
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Design and analysis of tensegrity power lines2012In: International Journal of Space Structures, ISSN 0956-0599, Vol. 27, no 2-3, 139-154 p.Article in journal (Refereed)
    Abstract [en]

    Overhead transmission power lines have undergone very small aesthetic and technical changes over time. Studies on mitigation of the electromagnetic field shows that utilizing a helix configuration is an effective way to reduce the electromagnetic field. This study proposes to use tensegrity structures as power lines. Tensegrity structures are composed of tension and compression elements in equilibrium. Modules, simple units with a certain rotation, are connected together to design of overhead power lines with considerable electromagnetic field reduction. A form-finding method enables the design of various free-form configurations. A parametric study is performed to investigate the influence of the module dimensions on the stiffness of the power line. A design algorithm was used for determining the optimum size of elements and the pre-stress level. The selected baseline structure was able to tolerate the wind and ice loads in severe conditions with a 50 times reduction in electromagnetic field. Finally a sensitivity analysis is performed to show the effects of element loss or damage.

  • 12.
    Eriksson, Anders
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Månsson, JohanKTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.Tibert, GunnarKTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    NSCM-17: Proceedings of the 17th Nordic Seminar on Computational Mechanics2004Conference proceedings (editor) (Refereed)
  • 13.
    Eriksson, Anders
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Tibert, GunnarKTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Proceedings of NSCM-23: the 23rd Nordic seminar on computational mechanics2010Conference proceedings (editor) (Other academic)
  • 14.
    Eriksson, Anders
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Redundant and force-differentiated systems in engineering and nature2006In: Computer Methods in Applied Mechanics and Engineering, ISSN 0045-7825, E-ISSN 1879-2138, Vol. 195, no 41-43, 5437-5453 p.Article in journal (Refereed)
    Abstract [en]

    Sophisticated load-carrying structures, in nature as well as man-made, share some common properties. A clear differentiation of tension, compression and shear is in nature primarily manifested in the properties of materials adapted to the efforts, whereas they in engineering are distributed on different components. For stability and failure safety, redundancy on different levels is also commonly used. The paper aims at collecting and expanding previous methods for the computational treatment of redundant and force-differentiated systems. A common notation is sought, giving and developing criteria for describing the diverse problems from a common structural mechanical viewpoint. From this, new criteria for the existence of solutions, and a method for treatment of targeted dynamic solutions are developed. Added aspects to previously described examples aim at emphasizing similarities and differences between engineering and nature, in the forms of a tension truss structure and the human musculoskeletal system.

  • 15.
    Falk, Andreas
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Architecture, Architectural Technologies.
    Samuelsson, Sture
    KTH, School of Architecture and the Built Environment (ABE), Architecture, Architectural Technologies.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Plate based tensegrity structures2005In: IASS 2005: Proceedings of the International Symposium on Shell and Spatial Structures, 2005Conference paper (Refereed)
  • 16. Ganga, P. L.
    et al.
    Micheletti, A.
    Podio-Guidugli, P.
    Scolamiero, L.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Zolesi, V.
    Tensegrity rings for deployable space antennas: Concept, design, analysis, and prototype testing2016In: Springer Optimization and Its Applications, Springer Publishing Company, 2016, 269-304 p.Conference paper (Refereed)
    Abstract [en]

    In this paper we describe a tensegrity ring of innovative conception for deployable space antennas. Large deployable space structures are mission-critical technologies for which deployment failure cannot be an option. The difficulty to fully reproduce and test on ground the deployment of large systems dictates the need for extremely reliable architectural concepts. In 2010, ESA promoted a study focused on the pre-development of breakthrough architectural concepts offering superior reliability. This study, which was performed as an initiative of ESA Small Medium Enterprises Office by Kayser Italia at its premises in Livorno (Italy), with Università di Roma TorVergata (Rome, Italy) as sub-contractor and consultancy from KTH (Stockholm, Sweden), led to the identification of an innovative large deployable structure of tensegrity type, which achieves the required reliability because of a drastic reduction in the number of articulated joints in comparison with non-tensegrity architectures. The identified target application was in the field of large space antenna reflectors. The project focused on the overall architecture of a deployable system and the related design implications. With a view toward verifying experimentally the performance of the deployable structure, a reduced scale breadboard model was designed and manufactured. A gravity off-loading system was designed and implemented, so as to check deployment functionality in a 1-g environment. Finally, a test campaign was conducted, to validate the main design assumptions as well as to ensure the concept’s suitability for the selected target application. The test activities demonstrated satisfactory stiffness, deployment repeatability, and geometric precision in the fully deployed configuration. The test data were also used to validate a finite element model, which predicts a good static and dynamic behavior of the full-scale deployable structure.

  • 17.
    Gärdsback, Mattias
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics.
    A Comparison of Rotation-Free Triangular Shell Elements for Unstructured Meshes2007In: Computer Methods in Applied Mechanics and Engineering, ISSN 0045-7825, E-ISSN 1879-2138, Vol. 196, no 49-52, 5001-5015 p.Article in journal (Refereed)
    Abstract [en]

    Many engineering applications require accurate and rapidly computed thin-shell elements. Rotation-free (RF) shell elements include the bending behaviour of thin shells without introducing any additional degrees of freedom compared to a membrane element. Instead, constant curvatures are approximated from the out-of-plane displacements of a patch of usually four triangular elements. A consequence of this is that the accuracy for irregular meshes has been unsatisfactory. The aim of this study is to find an RF shell element which is accurate also for unstructured meshes. The main difference between existing elements is whether they assume two-dimensional constant curvatures over the patch or use superposition of one-dimensional constant curvatures for the three pairs of triangles. The first assumption fulfils constant curvatures for a Kirchhoff plate exactly, whereas the second and most common assumption only approximates constant curvatures. The first assumption is significantly more resistant to element shape distortions, whereas the second assumption is slightly faster to compute and more appropriate on boundaries where one or more elements are missing or several neighbouring elements share a side. The combination is significantly more accurate for irregular meshes than other comparable RF elements for linear benchmark tests.

  • 18.
    Gärdsback, Mattias
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Deployment control of space webs2007In: Proceedings of the 20th Nordic Seminar on Computational Mechanics, 2007, 3.5-3.8 p.Conference paper (Other academic)
  • 19.
    Gärdsback, Mattias
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics.
    Deployment Control of Spinning Space Webs2009In: Journal of Guidance Control and Dynamics, ISSN 0731-5090, Vol. 32, no 1, 40-50 p.Article in journal (Refereed)
    Abstract [en]

    Space webs are lightweight cable nets deployable in space to serve as platforms for very large structures. Deployment and stabilization of large space webs by spin have gained interest because the rotational inertia forces are in the plane of rotation and the spin rate that determines the magnitude of the web tension can be chosen to meet the mission requirements. Nevertheless, a robust control method is required for a successful spin deployment. The control law used for the deployment of the Znamya-2 membrane reflector, for which a feedback-controlled torque is applied to the center hub, was applied here to a quadratic space web folded in arms coiled around the hub. To analyze the deployment, an analytical three-degree-of-freedom model and a fully three-dimensional finite element model were developed. The simulations indicate that it is favorable to deploy the web in just one step. It is also suggested that the simple analytical model can be used to determine important mission requirements such as the torque, power, and energy required for different deployment times.

  • 20.
    Gärdsback, Mattias
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Deployment simulations of space webs2007In: Proceedings of the 6th European LS-DYNA Users' Conference, 2007, 1.111-1.120 p.Conference paper (Other academic)
  • 21.
    Gärdsback, Mattias
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Evaluation of triangular shell elements for thin membrane structures2005In: Proceedings of the 5th International Conference on Computation of Shell and Spatial Structures, 2005Conference paper (Other academic)
  • 22.
    Gärdsback, Mattias
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Finding the most efficient rotation-free triangular shell element2005In: NSCM-18: Proceedings of the 18th Nordic Seminar on Computational Mechanics, 2005Conference paper (Other academic)
  • 23.
    Gärdsback, Mattias
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics.
    Optimal Deployment Control of Spinning Space Webs and Membranes2009In: Journal of Guidance Control and Dynamics, ISSN 0731-5090, Vol. 32, no 5, 1519-1530 p.Article in journal (Refereed)
    Abstract [en]

    Future solar sail and solar power satellite missions will consider using centrifugal forces for deployment and stabilization. Some of the main advantages with spin deployment are that the significant forces are in the plane of rotation, and a relatively simple control can be used and the tension in the membrane or web can be adjusted by the spin rate. Existing control strategies seem to either consume excessive energy or cause oscillations. In this study, control laws are derived from the solution to relevant optimal control problems and existing controls. The derived control laws are used in deployment simulations with both simple analytical three-degree-of-freedom models and a fully-three-dimensional finite element model. The results indicate that the derived control laws can be used to minimize the energy consumption and oscillations as for an optimal control, yet retain the simplicity of previous control laws.

  • 24.
    Gärdsback, Mattias
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics.
    Space webs2006Report (Other academic)
    Abstract [en]

    This report presents a study of the controlled deployment of a large web in space. The study is composed of three major parts:1. The design of the space web starts with a study of different geometries, i.e. threeor four corners. For each geometry, three different mesh topologies are investigated,i.e. triangular, square or hexagonal meshes. An analysis by the force method showedt hat only the web with a square mesh could be prestressed by a centrifugal forcefield. The triangular mesh had a too high degree of static indeterminacy, whichresulted in compressed elements. The hexagonal mesh had a too high degree ofkinematic indeterminacy and became too distorted under the centrifugal force field.The square mesh webs were subsequently analysed in terms of out-of-plane flexibilityand vibrational characteristics. Preliminary investigations on the choice of materialfor the web and the probability of web failure due to micro-meteoroid impact werealso performed. MATLAB routines that automatically generates the web with anarbitrary size, mesh width and sag-to-span ratio have been developed.2. A successful deployment requires an adequate folding pattern. A literature review identified the star-like folding pattern as a promising candidate. The folding is performedin two distinctive stages. First, the web is folded towards the central hub in a way so that three or four radial arms are formed, depending on the chosen geometry.Then, the radial arms can be either coiled around the central hub or folded ina zig-zag manner towards the hub. The MATLAB-generated web from part 1 is fed into new MATLAB routines, which folds the web according to the various pattern described above.3. The dynamic deployment of the space web is analysed by a two-dimensional analyticalmodel in MATLAB and a full three-dimensional model by the commercialfinite element software LS-DYNA. The developed analytical models can simulatethe deployment of the arms from a position coiled around the hub or reeled up onspools. A simple control strategy was found in literature and implemented in the analyticalmodel with successful results. The MATLAB-generated model of the foldedweb was inserted into the software LS-DYNA. For an uncontrolled deployment, thefinite element model yields the expected coiling off-coiling on oscillating behaviour.The control law with the drooping characteristics is not implemented in the finite element model, but analyses with a simplified control law shows good agreement between the analytical and the finite element results for the deployment of the stararms.

  • 25.
    Gärdsback, Mattias
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics.
    Izzo, D.
    Advanced Concepts Team, EUI-ACT, ESTEC, Keplerlaan.
    Design Considerations and Deployment Simulations of Spinning Space Webs2007In: 48th AIAA/ASME/ASCE/AHS/ASC Structures, Structual Dynamics and Materials Conrerence: Waikiki, HI; 23 April 2007 through 26 April 2007, 2007, 1503-1512 p.Conference paper (Refereed)
    Abstract [en]

    ESA Advanced Concepts Team (ACT) has proposed to construct large space antennas and solar power systems by deploying and stabilising a large web in space. The idea originates from the Japanese "Furoshiki Satellite". Since an overly complicated control system contributed to the partly chaotic deployment, ACT suggests to use centrifugal forces to deploy the space web. In this study the design and folding pattern of space webs are discussed. An analytical model and a finite element model used to describe the deployment, from the chosen folding, are presented. Free deployment of space webs is studied and a first control strategy that enables controlled and stable deployment is suggested.

  • 26.
    Ivchenko, Nickolay
    et al.
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Tibert, Gunnar
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Sounding rocket experiments with ejectable payloads at KTH2013In: 21st ESA Symposium: European Rocket & Balloon Programmes and Related Research / [ed] L. Ouwehand, ESTEC, Noordwijk, The Netherlands: ESA Communications , 2013, 503-510 p.Conference paper (Other academic)
    Abstract [en]

    Several experiments have been carried out or are in design phase under the lead of KTH using ejectable recoverable units to achieve variable scientific and technical objectives. This paper introduces the experiments withtheir goals, design solutions, results and lessons learned where appropriate. The RAIN (Rocket deployed Atmosphericprobes conducting Independent measurements in Northern Sweden) experiment used two radially ejected free flyers equipped with aerosol particle collection experiments. The MUSCAT (Multiple Spheres for Characterisation of Atmospheric Temperature) experiment used four free flyers ejected radially to retrieve the density, temperature and wind profiles. The ISAAC (Infrared Spectroscopy to Analyze the middle Atmosphere Composition) experiment will use two free flyers to derive the carbon dioxide by measuring the absorption of the infrared light on the line of sight between them. The SPIDER (Small Payloads for Investigation of Disturbances in Electrojet by Rockets) experiment will use a larger number (>4) of free flyers to measure electric and magnetic field, electron concentration and temperature in order to study the electrojet turbulence.

  • 27.
    Khoshparvar, Soheil
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Bylander, Lars
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Ivchenko, Nickolay
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Random vibration stress analysis of the BepiColombo boom deployment system2010In: Proceedings of the 23rd Nordic Seminar on Computational Mechanics / [ed] Anders Eriksson and Gunnar Tibert, Stockholm, Sweden: KTH Royal Institute of Technology, 2010, 108-111 p.Conference paper (Other academic)
  • 28.
    Magnusson, Patrick
    et al.
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Reid, William
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Achert, Peggy
    Stockholm University.
    Ivchenko, Nickolay
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Lindén, Erik
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Shepenkov, Valeriy
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Preliminary results from the RAIN mesospheric and stratospheric aerosol particle collection experiment launched on REXUS-112013In: 21st ESA Symposium: European Rocket & Balloon Programmes and Related Research / [ed] L. Ouwehand, ESTEC, Noordwijk, The Netherlands: ESA Communications , 2013, 511-517 p.Conference paper (Refereed)
    Abstract [en]

    The RAIN (Rocket deployed Atmospheric probes conducting Independent measurements in Northern Sweden) experiment demonstrates a technique for collecting aerosol particles in the middle atmosphere using multiple probes ejected from a sounding rocket. Collection samples on each probe are exposed over varying height ranges between 80 and 22 km giving an altitude distribution profile of aerosol particles. The experiment was launched on board the REXUS-11 sounding rocket on November 16, 2012 from Esrange Space Centre. The experiment operated nominally and was recovered. Initial scanning electron microscopy analysis of the collection samples indicates that aerosols were collected during the fall, however detailed analysis over all height ranges is ongoing.

  • 29.
    Mallol, Pau
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics.
    Mao, Huina
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Experiments and Simulations of the Deploymentof a Bi-stable Composite BoomManuscript (preprint) (Other (popular science, discussion, etc.))
    Abstract [en]

    The rapidly growing use of nano- and pico-satellites for space missions requires de-ployable systems to be highly storable yet large and with adequate mechanical properties when deployed. This paper focuses on the modeling and simulation of a meter-class passively deployable boom, based on the self-contained linear meter-class deployable(SIMPLE) boom by Thomas W. Murphey, exploiting the bi-stable nature of compositeshells. Experimental tests were carried on a boom prototype suspended in a gravityo-offloading system. The strain energy level, deployment time and spacecraft displacements calculated from the finite element method agree well with analytical analyses, confirming the theoretical accuracy of the finite element method. Since friction and strain energy relaxation were not accurately included in the model, the finite element simulations predict deployment times up to five times shorter than those of the gravity off-loaded boom experiments. The quick deployment and violent end-of-deployment shock create boom deployment dynamics which are not seen in the experiments. 

  • 30.
    Mallol, Pau
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Deployment modeling and experimental testing of a Bi-stable composite boom for small satellites2013In: 54th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, American Institute of Aeronautics and Astronautics, 2013Conference paper (Refereed)
    Abstract [en]

    The rapidly growing use of nano- and pico-satellites for space missions requires deployable systems to be highly storable yet large and with adequate mechanical properties when deployed. This paper focuses on the modeling and simulation of a meter-class passively deployable boom - based on the SIMPLE boom by Thomas W. Murphey - exploiting the bi-stable nature of composite shells. Experimental tests were also carried on a boom prototype suspended in a gravity off-loading system. The strain energy level, deployment time and spacecraft displacements of the models agree well with analytical analyses, confirming the theoretical accuracy of the finite element model. However, the simulations show that the boom deploys six times faster than the real prototype. The quick deployment and violent end-of-deployment shock provokes the boom deployment dynamics to be unrealistic but still shows a reasonable behavior given the nature of the deployment. Future improvements in the material and friction models will, most likely, provide us with a more realistic finite element model.

  • 31.
    Mallol, Pau
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Tibert, GunnarKTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Deployment modelling and experimental testing of a bi-stable composite boom for small satellites2013Conference proceedings (editor) (Other academic)
    Abstract [en]

    The rapidly growing use of nano- and pico-satellites for space missions requires deployable systems to be highly storable yet large and with adequate mechanical properties when deployed. This paper focuses on the modelling and simulation of a meter-class passively deployable boom – based on the SIMPLE boom by Thomas W. Murphey – exploiting the bi-stable nature of composite shells. Experimental tests were also carried on a boom prototype suspended in a gravity off-loading system. The strain energy level, deployment time and spacecraft displacements of the models agree well with analytical analyses, confirming the theoretical accuracy of the finite element model. However, the simulations show that the boom deploys six times faster than the real prototype. The quick deployment and violent end-of-deployment shock provokes the boom deployment dynamics to be unrealistic but still shows a reasonable behaviour given the nature of the deployment. Future improvements in the material and friction models will, most likely, provide us with a more realistic finite element model.

  • 32.
    Mallol, Pau
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Explicit dynamics simulations of the deployment of a composite boom for small satellitesManuscript (preprint) (Other academic)
  • 33.
    Mao, Huina
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Ganga, Pier Luigi
    Kayser Italia.
    Ghiozzi, Michele
    Kayser Italia.
    Ivchenko, Nickolay
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Deployment of Bistable Self-Deployable Tape Spring Booms Using a Gravity Offloading System2017In: Journal of Aerospace Engineering, ISSN 0893-1321, E-ISSN 1943-5525, Vol. 30, no 4Article in journal (Refereed)
    Abstract [en]

    Bistable tape springs are suitable as deployable structures thanks to their high packaging ratio, self-deployment ability, low cost, light weight, and stiffness. A deployable booms assembly composed of four 1-m long bistable glass fiber tape springs was designed for the electromagnetically clean 3U CubeSat Small Explorer for Advanced Missions (SEAM). The aim of the present study was to investigate the deployment dynamics and reliability of the SEAM boom design after long-term stowage using onground experiments and simulations. A gravity offloading system (GOLS) was built and used for the onground deployment experiments. Two booms assemblies were produced and tested: a prototype and an engineering qualification model (EQM). The prototype assembly was deployed in a GOLS with small height, whereas the EQM was deployed in a GOLS with tall height to minimize the effects of the GOLS. A simple analytical model was developed to predict the deployment dynamics and to assess the effects of the GOLS and the combined effects of friction, viscoelastic relaxation, and other factors that act to decrease the deployment force. Experiments and simulations of the deployment dynamics indicate significant viscoelastic energy relaxation phenomena, which depend on the coiled radius and stowage time. In combination with friction effects, these viscoelastic effects decreased the deployment speed and the end-of-deployment shock vibrations. 

  • 34.
    Mao, Huina
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Shipsha, Anton
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Design and Analysis of Laminates for Self-Deployment of Viscoelastic Bistable Tape Springs after Long-Term Stowage2017In: Journal of applied mechanics, ISSN 0021-8936, E-ISSN 1528-9036, Vol. 84, no 7, 071004Article in journal (Refereed)
    Abstract [en]

    Bistable tape springs are ultrathin fiber-reinforced polymer composites, which could self-deploy through releasing stored strain energy. Strain energy relaxation is observed after long-term stowage of bistable tape springs due to viscoelastic effects and the tape springs might lose their self-deployment abilities. In order to mitigate the viscoelastic effects and thus ensure self-deployment, different tape springs were designed, manufactured, and tested. Deployment experiments show that a four-layer, [â '45/0/90/45], plain weave glass fiber tape spring has a high capability to mitigate the strain energy relaxation effects to ensure self-deployment after long-term stowage in a coiled configuration. The two inner layers increase the deployment force and the outer layers are used to generate the bistability. The presented four-layer tape spring can self-deploy after more than six months of stowage at room temperature. A numerical model was used to assess the long-term stowage effects on the deployment capability of bistable tape springs. The experiments and modeling results show that the viscoelastic strain energy relaxation starts after only a few minutes after coiling. The relaxation shear stiffness decreases as the shear strain increases and is further reduced by strain energy relaxation when a constant shear strain is applied. The numerical model and experiments could be applied in design to predict the deployment force of other types of tape springs with viscoelastic and friction effects included.

  • 35.
    Mao, Huina
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Shipsha, Anton
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Design and analysis of laminates for self-deployment of viscoelastic bi-stable tape springs after long-term stowageManuscript (preprint) (Other (popular science, discussion, etc.))
    Abstract [en]

    Bi-stable tape springs are ultra-thin fiber-reinforced polymers composites, which could self-deploy through releasing stored strain energy. Strain energy relaxation is observed after long-term stowage of bi-stable tape springs due to viscoelastic effects and the tape springs might lose their self-deployment abilities. In order to mitigate the viscoelastic effects and thus ensure self-deployment, different tape springs were designed, manufactured and tested. Deployment experiments show that a 4-layer, [-45/0/90/45], plain weave glass fiber tape spring has ahigh capability to mitigate the strain energy relaxation effects to ensure self-deployment after long-term stowage in a coiled configuration. The two inner layers increase the deployment force and the outer layers are used to generate the bi-stability. The presented 4-layer tape spring can self-deploy after more than 6 months of stowage at room temperature. A numerical model was used to assess the long-term stowage effects on the deployment capability of bi-stable tape springs. The experiments and modeling results show that the viscoelastic strain energy relaxationstarts after only a few minutes after coiling. The relaxation shear stiffness decreases as the shear strain increases and is further reduced by strain energy relaxation when a constant shear strain is loaded. The numerical model and experiments could be applied in design to predict the deployment force of other types of tape springs with viscoelastic and friction effects included.

  • 36.
    Mao, Huina
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Sinn, T.
    Vasile, M.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Simulation and control of a space web deployed by centrifugal forces in a sounding rocket experiment2016In: AIAA Modeling and Simulation Technologies Conference, 2016, American Institute of Aeronautics and Astronautics Inc, AIAA , 2016Conference paper (Refereed)
    Abstract [en]

    A deployable space web is a flexible structure that can act as a lightweight platform for construction of large structures in space. In order to save space and energy for small deployable structures, a one-step deployment method was a possible choice for future web deployment without complicated extending mechanisms. The aim of the Suaineadh experiment was to deploy and stabilize a space web by centrifugal forces and act as a test bed of the one-step deployment. Suaineadh, a 2 × 2 m2 space web, was ejected from the nose cone of REXUS-12 sounding rocket and deployed in a micro-gravity environment. A developed control law and a reaction wheel were used to control the deployment. Results from ground tests, simulations and former sounding rocket experiments were used to design the structure, folding pattern, control parameters and the deployment. During the experiment, the web was deployed but entanglements occurred since the web did not start to deploy at the specified proper initial angular velocity. It might be due to the broken inertial measurement unit which failed to detect the required spin rate of the hub or other unknown problems. The deployment dynamics was reconstructed from the information recorded by inertial measurement units and cameras. Simulations show that if the Suaineadh space web started to deploy at the specified proper angular velocity, the web would most likely have been deployed and stabilized in space by the motor, reaction wheel and controller used in the experiment. In actual flight, out-of-plane motions were observed both in deployment and stabilization phases. In order to stabilize the out-of-plane motions and reduce the risk of entanglement observed from experiment, simulation results show that small reaction wheels could be used before or during web deployment. Tape springs could also be used as web arms to avoid entanglement.

  • 37.
    Mao, Huina
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Sinn, Thomas
    Vasile, Massimiliano
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Post-launch analysis of the deployment dynamics of a space web sounding rocket experiment2016In: Acta Astronautica, ISSN 0094-5765, E-ISSN 1879-2030, Vol. 127, 345-358 p.Article in journal (Refereed)
    Abstract [en]

    Lightweight deployable space webs have been proposed as platforms or frames for a construction of structures in space where centrifugal forces enable deployment and stabilization. The Suaineadh project was aimed to deploy a 2 x 2 m2 space web by centrifugal forces in milli-gravity conditions and act as a test bed for the space web technology. Data from former sounding rocket experiments, ground tests and simulations were used to design the structure, the folding pattern and control parameters. A developed control law and a reaction wheel were used to control the deployment. After ejection from the rocket, the web was deployed but entanglements occurred since the web did not start to deploy at the specified angular velocity. The deployment dynamics was reconstructed from the information recorded in inertial measurement units and cameras. The nonlinear torque of the motor used to drive the reaction wheel was calculated from the results. Simulations show that if the Suaineadh started to deploy at the specified angular velocity, the web would most likely have been deployed and stabilized in space by the motor, reaction wheel and controller used in the experiment.

  • 38.
    Mao, Huina
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    EXPERIMENTS AND ANALYTICAL MODELING FOR DESIGNING TAPE SPRING COMPOSITESManuscript (preprint) (Other (popular science, discussion, etc.))
    Abstract [en]

    Lightweight fiber reinforced tape spring composites are proposed for deployable space structures for nanosatellites. Neutral stable carbon fiber tape springs and bi-stable glass fiber tape springs were manufactured and their self-deployabilities after stowage were experimentally tested. The viscoelastic effects of the composites used were experimentally investigated. An analysis methodology that predicts neutral stability or bi-stability in appropriately arranging fiber directions, layups and fabric properties is presented. A design method flowchart is presented to give a reference for designing neutral or bi-stable tape springs based on the experiments and the analytical model, e.g., material type, layup, fibers direction andstability parameters. The tape spring properties before and after stowage can be predicted. The analytical model shows that fabrics of high strength fibers and low shear modulus resin with layer angle ±45o are good choices for neutrally tape springs and adding inner 0o/90o layers can increase the deployment force for bi-stable tape springs. The bi-stable glass fiber tape springs that can self-deploy after more than 6 months of stowage and high strength carbon fiber neutrally tape springs were fabricated.

  • 39.
    Martinsson Achi, Lina
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Architecture, Architectural Technologies.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    A graph theoretical methodology for conceptual design2012In: IASS-APCS 2012: Proceedings of the International Symposium on Shell and Spatial Structures, 2012Conference paper (Refereed)
  • 40.
    Prigent, Yoann
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics.
    Mallol, Pau
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    A classical lamination model of bi-stable woven composite tape-springs2011In: Proceedings of the 24th Nordic Seminar on Computational Mechanics / [ed] Jouni Freund and Reijo Kouhia, Department of Civil and Structural Engineering, Aalto University , 2011, 51-54 p.Conference paper (Refereed)
    Abstract [en]

    This extended abstract presents the work done so far on modeling woven composite materials, specifically two carbon fiber reinforced plastics materials: twill and plain weave. The material model has been initially verified against data available in a database.

  • 41.
    Reid, William
    et al.
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Achtert, P.
    Ivchenko, Nickolay
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Magnusson, Patrick
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Kuremyr, Tobias
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Shepenkov, Valeriy
    KTH, School of Engineering Sciences (SCI), Solid Mechanics (Dept.).
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Technical Note: A novel rocket-based in situ collection technique for mesospheric and stratospheric aerosol particles2013In: Atmospheric Measurement Techniques, ISSN 1867-1381, E-ISSN 1867-8548, Vol. 6, no 3, 777-785 p.Article in journal (Refereed)
    Abstract [en]

    A technique for collecting aerosol particles between altitudes of 17 and 85 km is described. Spin-stabilized collection probes are ejected from a sounding rocket allowing for multi-point measurements. Each probe is equipped with 110 collection samples that are 3 mm in diameter. The collection samples are one of three types: standard transmission electron microscopy carbon grids, glass fibre filter paper or silicone gel. Collection samples are exposed over a 50 m to 5 km height range with a total of 45 separate ranges. Post-flight electron microscopy will give size-resolved information on particle number, shape and elemental composition. Each collection probe is equipped with a suite of sensors to capture the probe's status during the fall. Parachute recovery systems along with GPS-based localization will ensure that each probe can be located and recovered for post-flight analysis.

  • 42.
    Russell, Colin
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Deployment of tensegrity frameworks using inflatable tubes2005In: Structural Membranes 2005: Proceedings of the International Conference on Textile Composites and Inflatable Structures, 2005Conference paper (Other academic)
  • 43.
    Russell, Colin
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Deployment simulations of inflatable tensegrity structures2008In: International Journal of Space Structures, ISSN 0956-0599, Vol. 23, no 2, 63-77 p.Article in journal (Refereed)
    Abstract [en]

    nsegrity structures are attractive as deployable space structures since they are composed mainly of flexible tension members and can thus easily be folded. To automatically deploy such structures it is proposed that the tension members are replaced or enclosed by thin-film tubes, which form a continuous volume. The structure deploys when this volume is pressurised. This concept was studied by numerical simulations of the deployment process in a zero-gravity environment using the control volume method for the fluid-structure interaction. First, single z-folded and coiled tubes were analysed to determine suitable element size, number of control volumes and gas flow rate. Then one- and three-stage tensegrity masts were modelled, folded and finally deployed. The study showed that the deployment concept is feasible.

  • 44.
    safaei, Seif
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics.
    Eriksson, Anders
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Micheletti, A.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Study of various tensegrity modules as building blocks for slender booms2013In: International Journal of Space Structures, ISSN 0956-0599, Vol. 28, no 1, 41-52 p.Article in journal (Refereed)
    Abstract [en]

    This study investigates the structural performance of long and slender tensegrity booms. Previous studies show that tensegrity structures are generally more flexible than conventional trusses or space frames. The aims here were (i) to quantify how much more flexible eleven different tensegrity booms are, when compared to state-of-the-art truss booms, (ii) to find a general explanation for this. The performance criterion used for the comparison was the first natural frequency of the boom. A finite element program with truss elements was used to compute the natural frequencies around the initial prestressed configurations. The results show that tensegrity booms have between one and three orders of magnitude lower natural frequencies than truss booms. It is concluded that for the best performing tensegrity booms, the bending stiffness is independent of the level of pre-stress and the number of infinitesimal mechanisms as the bending stiffness is given mainly by the material stiffness of the tension elements and not the geometric stiffness as the infinitesimal mechanisms are not activated by bending. Thus, whereas the level of pre-stress and the presence of infinitesimal mechanisms play major roles for the stiffness of some tensegrity structures, the axial stiffness and orientation of tension elements are most important for the studied slender booms.

  • 45. Sinn, T.
    et al.
    Brown, R.
    McRobb, M.
    Wujek, Adam
    KTH, School of Information and Communication Technology (ICT), Electronic Systems.
    Lowe, C.
    Weppler, J.
    Parry, T.
    Yarnoz, D. G.
    Brownlie, F.
    Skogby, Jerker
    KTH, School of Information and Communication Technology (ICT), Electronic Systems.
    Dolan, I.
    De Franca Queiroz, T.
    Rogberg, Fredrik
    KTH, School of Information and Communication Technology (ICT), Electronic Systems.
    Donaldson, N.
    Clark, R.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Lessons learned from three university experiments onboard the REXUS/BEXUS sounding rockets and stratospheric balloons2013In: 64th International Astronautical Congress 2013, International Astronautical Federation, 2013, 7965-7976 p.Conference paper (Refereed)
    Abstract [en]

    Over the last three years the authors have been involved in three experiments that were or will be launched on sounding rockets and high altitude balloons with the REXUS/BEXUS program (Rocket-borne / Balloon-borne Experiments for University Students). The first experiment, called Suaineadh was launched from Esrange (Kiruna, Sweden) onboard REXUS 12 in March 2012. Suaineadh had the purpose of deploying a web in space by using centrifugal forces. The payload was lost during re-entry but was recovered 18 month later in early September 2013. StrathSat-R is the second experiment, which had the purpose of deploying two cube satellites with inflatable structures from the REXUS 13 sounding rocket, was launched first in May 2013 and will be launched a second time in spring 2014. The last experiment is the iSEDE experiment which has the goal of deploying an inflatable structure with disaggregated electronics from the high altitude balloon BEXUS15/16 in October 2013. All these experiments have been designed, built and flown in a timeframe of one and a half to two years. This paper will present the lessons learned in project management, outreach, experiment design, fabrication and manufacturing, software design and implementation, testing and validation as well as launch, flight and post-flight. Furthermore, the lessons learned during the recovery mission of Suaineadh will be discussed as well. All these experiments were designed, built and tested by a large group of university students of various disciplines and different nationalities. StrathSat-R and iSEDE were built completely at Strathclyde but the Suaineadh experiment was a joint project between Glasgow and Stockholm which was especially tricky during integration while approaching the experiment delivery deadline. This paper should help students and professionals across various disciplines to build and organise these kinds of projects more efficiently without making the same, sometimes expensive, mistakes all over again.

  • 46. Sinn, T.
    et al.
    McRobb, M.
    Wujek, Adam
    KTH, School of Information and Communication Technology (ICT), Electronic Systems.
    Skogby, Jerker
    KTH, School of Information and Communication Technology (ICT), Electronic Systems.
    Rogberg, Fredrik
    KTH, School of Electrical Engineering (EES).
    Wang, Junyi
    KTH, School of Electrical Engineering (EES).
    Vasile, M.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Results of rexus12's suaineadh experiment: Deployment of a spinning space web in micro gravity conditions2012In: Proceedings of the International Astronautical Congress, IAC: Volume 2, 2012, International Astronautical Federation, 2012, 803-810 p.Conference paper (Refereed)
    Abstract [en]

    On the 19th of March 2012, the Suaineadh experiment was launched onboard the sounding rocket REXUS12 (Rocket Experiments for University Students) from the Swedish launch base ESRANGE in Kiruna. The Suaineadh experiment served as a technology demonstrator for a space web deployed by a spinning assembly. The deployment of this web is a stepping stone for the development of ever larger structures in space. Such a structure could serve as a substructure for solar arrays, transmitters and/or antennas. The team was comprised of students from the University of Strathclyde (Glasgow, UK), the University of Glasgow (Glasgow, UK) and the Royal Institute of Technology (Stockholm, Sweden), designing, manufacturing and testing the experiment over the past 24 months. Following launch, the experiment was ejected from the ejection barrel located within the nosecone of the rocket. Centrifugal forces acting upon the space webs spinning assembly were used to stabilise the experiment's platform. A specifically designed spinning reaction wheel, with an active control method, was used. Once the experiment's motion was controlled, a 2 m by 2 m space web is released. Four daughter sections situated in the corners of the square web served as masses to stabilise the web due to the centrifugal forces acting on them. The four daughter sections contained inertial measurement units (IMUs). Each IMU provided acceleration and velocity measurements in all three directions. Through this, the positions of the four corners could be found through integration with respect to known time of the accelerations and rotations. Furthermore, four cameras mounted on the central hub section captured high resolution imagery of the deployment process. After the launch of REXUS12, the recovery helicopter was unable to locate the ejected experiment, but 22 pictures were received over the wireless connection between the experiment and the rocket. The last received picture was taken at the commencement of web deployment. Inspection of these pictures allowed the assumption that the experiment was fully functional after ejection, but perhaps through tumbling of either the experiment or the rocket, the wireless connection was interrupted. A recovery mission in the middle of August was only able to find the REXUS12 motor and the payload impact location.

  • 47. Sinn, T.
    et al.
    Vasile, M.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Design and development of deployable Self-inflating Adaptive Membrane2012In: 53rd Structures, Structural Dynamics, and Materials Conference (SDM) 2012, American Institute of Aeronautics and Astronautics, 2012, AIAA 2012-1517- p.Conference paper (Refereed)
    Abstract [en]

    Space structures nowadays are often designed to serve just one objective during their mission life, examples include truss structures that are used as support structures, solar sails for propulsion or antennas for communication. Each and every single one of these structures is optimized to serve just their distinct purpose and are more or less useless for the rest of the mission and therefore dead weight. By developing a smart structure that can change its shape and therefore adapt to different mission requirements in a single structure, the flexibility of the spacecraft can be increased by greatly decreasing the mass of the entire system. This paper will introduce such an adaptive structure called the Self-inflating Adaptive Membrane (SAM) concept which is being developed at the Advanced Space Concepts Laboratory of the University of Strathclyde. An idea presented in this paper is to adapt these basic changeable elements from nature's heliotropism. Heliotropism describes a movement of a plant towards the sun during a day; the movement is initiated by turgor pressure change between adjacent cells. The shape change of the global structure can be significant by adding up these local changes induced by local elements, for example the cell's length. To imitate the turgor pressure change between the motor cells in plants to space structures, piezoelectric micro pumps are added between two neighboring cells. A passive inflation technique is used for deploying the membrane at its destination in space. The trapped air in the spheres will inflate the spheres when subjected to vacuum, therefore no pump or secondary active deployment methods are needed. The paper will present the idea behind the adaption of nature's heliotropism principle to space structures. The feasibility of the residual air inflation method is verified by LS-DYNA simulations and prototype bench tests under vacuum conditions. Additionally, manufacturing techniques and folding patterns are presented to optimize the actual bench test structure and to minimize the required storage volume. It is shown that through a bio-inspired concept, a high ratio of adaptability of the membrane can be obtained. The paper concludes with the design of a technology demonstrator for a sounding rocket experiment to be launched in March 2013 from the Swedish launch side Esrange.

  • 48.
    Sinn, Thomas
    et al.
    University of Strathclyde.
    McRobb, Malcolm
    University of Strathclyde.
    Wujek, Adam
    KTH, School of Information and Communication Technology (ICT), Electronic Systems.
    Skogby, Jerker
    KTH, School of Information and Communication Technology (ICT), Electronic Systems.
    Rogberg, Fredrik
    KTH, School of Electrical Engineering (EES).
    Wang, Junyi
    KTH, School of Electrical Engineering (EES).
    Vasile, Massimiliano
    University of Strathclyde.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Lessons learned from REXUS12'S suaineadh experiment: Spinning deployment of a space Web in milli gravity2013In: 21st ESA Symposium: European Rocket & Balloon Programmes and Related Research / [ed] L. Ouwehand, ESA Communications , 2013, 329-338 p.Conference paper (Refereed)
    Abstract [en]

    On the 19th of March 2012, the Suaineadh experiment was launched onboard the sounding rocket REXUS 12 (Rocket Experiments for University Students) from the Swedish launch base ESRANGE in Kiruna. The Suaineadh experiment served as a technology demonstrator for a space web deployed by a spinning assembly. Following launch, the experiment was ejected from the ejection barrel located within the nosecone of the rocket. Centrifugal forces acting upon the space web spinning assembly were used to stabilise the experiment's platform. A specifically designed spinning reaction wheel, with an active control method, was used. Once the experiment's motion was controlled, a 2 m by 2 m space web is released. Four daughter sections situated in the corners of the square web served as masses to stabilise the web due to the centrifugal forces acting on them. The four daughter sections contained inertial measurement units (IMUs). After the launch of REXUS 12, the recovery helicopter was unable to locate the ejected experiment, but 22 pictures were received over the wireless connection between the experiment and the rocket. The last received picture was taken at the commencement of web deployment. Inspection of these pictures allowed the assumption that the experiment was fully functional after ejection, but probably through tumbling of either the experiment or the rocket, the wireless connection was interrupted. A recovery mission in the middle of August was only able to find the REXUS 12 motor and the payload impact location.

  • 49. Sinn, Thomas
    et al.
    McRobb, Malcolm
    Wujek, Adam
    KTH, School of Information and Communication Technology (ICT).
    Skogby, Jerker
    KTH, School of Information and Communication Technology (ICT).
    Rogberg, Fredrik
    KTH, School of Electrical Engineering (EES).
    Wang, Junyi
    KTH, School of Electrical Engineering (EES).
    Vasile, Massimiliano
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Mao, Huina
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    THE EXPERIMENT THAT CAME FROM THE COLD: RESULTS FROM THE RECOVERED REXUS12 SUAINEADH SPINNING WEB EXPERIMENT2015In: EUROPEAN ROCKET AND BALLOON: PROGRAMMES AND RELATED RESEARCH, 2015, 449-459 p.Conference paper (Refereed)
    Abstract [en]

    The Suaineadh experiment had the purpose to deploy a 2m x 2m web in milli gravity conditions by using the centrifugal forces acting on corner sections of a web that is spinning around a central hub. Continuous exploration of our solar system and beyond requires ever larger structures in space. But the biggest problem nowadays is the transport of these structures into space due to launch vehicle payload volume constrains. By making the space structures deployable with minimum storage properties, this constrain may be bypassed. Deployable concepts range from inflatables, foldables, electrostatic to spinning web deployment. The advantage of the web deployment is the very low storage volume and the simple deployment mechanism. These webs can act as lightweight platforms for the construction of large structures in space without the huge expense of launching heavy structures from Earth. The Suaineadh experiment was launched onboard the sounding rocket REXUS12 in March 2012. After achieving the required altidue, the Suaineadh experiment was ejected from the rocket in order to be fully free flying. A specially designed spinning wheel in the ejected section was then used to spin up the experiment until the required rate is achieved for web deployment to commence. Unfortunately during re-entry, the probe was lost and also a recovery mission in August 2012 was only able to find minor components of the experiment. After 18 month, in September 2013, the experiment was found in the wilderness of Northern Sweden. In the following months all data from the experiment could be recovered. The images and accelerometer data that has been analysed showed the deployment of the web and a very interesting three dimensional behaviour that differs greatly from on ground two dimensional prototype tests. This paper will give an overview on the recovered data and it will present the analysed results of the Suaineadh spinning web experiment.

  • 50.
    Sinn, Thomas
    et al.
    University of Strathclyde.
    McRobb, Malcolm
    University of Glasgow.
    Wujek, Adam
    KTH, School of Information and Communication Technology (ICT), Electronic Systems.
    Skogby, Jerker
    KTH, School of Information and Communication Technology (ICT), Electronic Systems.
    Zhang, Mengqi
    KTH, School of Engineering Sciences (SCI), Mechanics.
    Vasile, Massimiliano
    University of Strathclyde.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Weppler, Johannes
    University of Stuttgart.
    Feeney, Andrew
    University of Glasgow.
    Russell, John
    University of Glasgow.
    Rogberg, Fredrik
    KTH, School of Electrical Engineering (EES).
    Wang, Junyi
    KTH, School of Electrical Engineering (EES).
    REXUS 12 Suaineadh experiment: deployment of a web in microgravity conditions using centrifugal forces2011In: IAC 2011: Proceedings of the 62nd International Astronautical Congress, 2011, IAC-11-A2.3.7- p.Conference paper (Refereed)
12 1 - 50 of 74
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