Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Strength analysis and modeling of hybrid composite-aluminum aircraft structures
Linköping University, Department of Management and Engineering, Solid Mechanics. Linköping University, The Institute of Technology.
2013 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

The current trend in aircraft design is to increase the proportion of fiber composites in the structures. Since many primary parts also are constructed using metals, the number of hybrid metal-composite structures is increasing. Such structures have traditionally often been avoided as an option because of the lack of methodology to handle the mismatch between the material properties. Composite and metal properties differ with respect to: thermal expansion, failure mechanisms, plasticity, sensitivity to load type, fatigue accumulation and scatter, impact resistance and residual strength, anisotropy, environmental sensitivity, density etc. Based on these differences, the materials are subject to different design and certification requirements. The issues that arise in certification of hybrid structures are: thermally induced loads, multiplicity of failure modes, damage tolerance, buckling and permanent deformations, material property scatter, significant load states etc. From the design point of view, it is a challenge to construct a weight optimal hybrid structure with the right material in the right place. With a growing number of hybrid structures, these problems need to be addressed. The purpose of the current research is to assess the strength, durability and thermo-mechanical behavior of a hybrid composite-aluminum wing structure by testing and analysis. The work performed in this thesis focuses on the analysis part of the research and is divided into two parts. In the first part, the theoretical framework and the background are outlined.Significant material properties, aircraft certification aspects and the modeling framework are discussed.In the second part, two papers are appended. In the first paper, the interaction of composite and aluminum, and their requirements profiles,is examined in conceptual studies of the wing structure. The influence of the hybrid structure constitution and requirement profiles on the mass, strength, fatigue durability, stability and thermo-mechanical behavior is considered. Based on the conceptual studies, a hybrid concept to be used in the subsequent structural testing is chosen. The second paper focuses on the virtual testing of the wing structure. In particular, the local behavior of hybrid fastener joints is modeled in detail usingthe finite element method, and the result is then incorporated into a global model using line elements. Damage accumulation and failure behavior of the composite material are given special attention. Computations of progressive fastener failure in the experimental setup are performed. The analysis results indicate the critical features of the hybrid wing structure from static, fatigue, damage tolerance and thermo-mechanical points of view.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2013. , 54 p.
Series
Linköping Studies in Science and Technology. Thesis, ISSN 0280-7971 ; 1590
National Category
Aerospace Engineering
Identifiers
URN: urn:nbn:se:liu:diva-91894Local ID: LIU–TEK–LIC–2013:24ISBN: 978-91-7519-628-2 (print)OAI: oai:DiVA.org:liu-91894DiVA: diva2:619506
Presentation
2013-05-24, Hus A, plan 3, föreläsningssal A35, Campus Valla, Linköping University, Linköping, 10:15 (Swedish)
Opponent
Supervisors
Available from: 2013-05-08 Created: 2013-05-03 Last updated: 2013-05-08Bibliographically approved
List of papers
1. Conceptual studies of a composite-aluminum hybrid wing box demonstrator
Open this publication in new window or tab >>Conceptual studies of a composite-aluminum hybrid wing box demonstrator
2014 (English)In: Aerospace Science and Technology, ISSN 1270-9638, E-ISSN 1626-3219, Vol. 32, no 1, 42-50 p.Article in journal (Refereed) Published
Abstract [en]

This paper presents a study of two different hybrid composite-aluminum concepts applied to a winglike structure which is exposed to mechanical  and thermal load. The aim of the study is to determine the most suitable  hybrid concept to later on be used in structural fatigue and static testing. In both concepts, the mass is optimized with respect to two different sets of requirements, one of which is currently in use in the fighter aircraft industry and one which is a modified version of the current requirement set. The issues considered in the study are mass, thermal behavior, buckling, bolted joints, failure criteria and fatigue damage, and they are examined in the frame of both requirement sets. The results clearly indicate the order of criticality between the different criteria in the different parts of each concept. Also, the comparison of two requirement sets gives an idea of the degree of influence of the modified criteria on the hybrid concepts and their mass. Based on the mass and the structural behavior in a thermal-mechanical loading one of the hybrid concepts is chosen for further studies and testing.

Place, publisher, year, edition, pages
Elsevier, 2014
Keyword
Hybrid structure, Wing structure, Composite-aluminum, Thermal load, Conceptual study
National Category
Aerospace Engineering
Identifiers
urn:nbn:se:liu:diva-91892 (URN)10.1016/j.ast.2013.11.002 (DOI)000331921900006 ()
Available from: 2013-05-03 Created: 2013-05-03 Last updated: 2017-12-06Bibliographically approved
2. Finite element modeling of mechanically fastened composite-aluminum joints in aircraft structures
Open this publication in new window or tab >>Finite element modeling of mechanically fastened composite-aluminum joints in aircraft structures
2014 (English)In: Composite structures, ISSN 0263-8223, E-ISSN 1879-1085, Vol. 109, 198-210 p.Article in journal (Refereed) Published
Abstract [en]

A three-dimensional, solid finite element model of a composite-aluminum single-lap bolted joint with a countersunk titanium fastener is developed. The model includes progressive damage behavior of the composite and a plasticity model for the metals. The response to static loading is compared to experimental results from the literature. It is shown that the model predicts the initiation and the development of the damage well, up to failure load. The model is used to evaluate the local force-displacement responses of a number of single-lap joints installed in a hybrid composite-aluminum wing-like structure. A structural model is made where the fasteners are represented by two-node connector elements which are assigned the force-displacement characteristics determined by local models. The behavior of the wing box is simulated for bending and twisting loads applied together with an increased temperature and the distribution of fastener forces and the progressive fastener failure is studied. It is shown that the fastener forces caused by the temperature difference are of significant magnitude and should be taken into account in the design of hybrid aircraft structures. It is concluded that, the account of the non-linear response of the joints results in a less conservative load distribution at ultimate failure load.

Place, publisher, year, edition, pages
Elsevier, 2014
Keyword
Bolted joints, Composite-aluminum, Finite element modeling, Hybrid wing structures
National Category
Aerospace Engineering
Identifiers
urn:nbn:se:liu:diva-91893 (URN)10.1016/j.compstruct.2013.10.056 (DOI)000331671700020 ()
Available from: 2013-05-03 Created: 2013-05-03 Last updated: 2017-12-06Bibliographically approved

Open Access in DiVA

Strength analysis and modeling of hybrid composite-aluminum aircraft structures(1096 kB)3802 downloads
File information
File name FULLTEXT01.pdfFile size 1096 kBChecksum SHA-512
9a32a4dece554e574d3c974906ce246d28f4afba85f5224fd5351f0fd102349a1df0811b7a3762fe1d5974594626b22117f926b3d2c68a2a26e9e8ac6bd71e39
Type fulltextMimetype application/pdf
omslag(162 kB)91 downloads
File information
File name COVER01.pdfFile size 162 kBChecksum SHA-512
fabe565e3a1f82a23fb7d3c0e30a7944664903025d47af823638962a0efe422ed5ddf40636b03ba4de7c6c50c03dad54dc7a026219cd196362dffa22ccae7b6c
Type coverMimetype application/pdf

Search in DiVA

By author/editor
Kapidzic, Zlatan
By organisation
Solid MechanicsThe Institute of Technology
Aerospace Engineering

Search outside of DiVA

GoogleGoogle Scholar
Total: 3802 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 586 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf