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Discrete element simulation of elasto-plastic shock waves in high-velocity compaction
KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
2011 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Elasto-plastic shock waves in high-velocity compaction of spherical metal particles are the focus of this thesis which consists of four papers (A-D). The compaction process is modeled by a discrete element method while using elastic and plastic loading, elastic unloading and adhesion at contacts.

Paper A investigates the dynamic compaction of a one-dimensional chain of homogenous particles. The development of the elasto-plastic shock waves, its propagation and influence on the compaction process are examined. Simulations yield information on the contact behavior, velocity of the particle and its deformation during dynamic compaction. Effects of changing loading parameters on the compaction process are also discussed.

Paper B addresses the non-homogeneity in a chain having; particles of different sizes and materials, voids between the particles and particles with/without adhesion between them.

Simulations show transmission and reflection of elasto-plastic shock wave during compaction process. The particle deformation during incident and reflected shocks and particle velocity fluctuations due to voids between particles are simulated. The effects of adhesion on particles separation during unloading stage are also discussed.

Paper C develops a simulation model for a high-velocity compaction process with auxiliary pistons, known as relaxation assists, in a compaction assembly. The simulation results reveals that the relaxation assists offer; smooth compaction during loading stage, prevention of  the particle separation during unloading stage and conversion of  higher kinetic energy of hammer into particles deformation.  Furthermore, the influence of various loading elements on compaction process is investigates. These results support the findings of experimental work.

Paper D further extends the one-dimensional case of Paper A and B into two-dimensional assembly of particles while adding friction between particles and between particles and container walls. Three particular cases are investigated including closely packed hexagonal, loosely packed random and a non-homogenous assembly of particles of various sizes and materials. Consistent with the one-dimensional case, primary interest is the linking of particle deformation with the elasto-plastic shock wave propagation. Simulations yield information on particle deformation during shock propagation and change in overall particles compaction with the velocity of the hammer. The force exerted by particles on the container walls and rearrangement of the loosely packed particles during dynamic loading are also investigated. Finally, the effects of presence of friction and adhesion on both overall particles deformation and compaction process are simulated.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology , 2011. , v, 44 p.
Series
Trita-AVE, ISSN 1651-7660 ; 2011:17
Keyword [en]
High-velocity compaction, Discrete element method, Plastic deformaiton, dynaimic loading, elasto-plastic shock wave, Friction, Adhesion
National Category
Physical Sciences
Research subject
Järnvägsgruppen - Ljud och vibrationer
Identifiers
URN: urn:nbn:se:kth:diva-31144ISBN: 978-91-7415-905-9OAI: oai:DiVA.org:kth-31144DiVA: diva2:402826
Public defence
2011-03-29, F3, Lindstedtsvägen 26, KTH, Stockholm, 10:00 (English)
Opponent
Supervisors
Note
QC 20110311Available from: 2011-03-11 Created: 2011-03-09 Last updated: 2011-03-11Bibliographically approved
List of papers
1. Discrete element simulation of elasto-plastic shock wave propagation in spherical particles
Open this publication in new window or tab >>Discrete element simulation of elasto-plastic shock wave propagation in spherical particles
2011 (English)In: Advances in Acoustics and Vibration, ISSN 1687-6261, E-ISSN 1687-627X, 123695Article in journal (Refereed) Published
Abstract [en]

Elasto-plastic shock wave propagation in a one-dimensional assembly of spherical metal particles is presented by extending well established quasi-static compaction models. The compaction process is modeled by a discrete element method while using elastic and plastic loading, elastic unloading and adhesion at contacts with typical dynamic loading parameters. Of particular interest is to study the development of the elasto-plastic shock wave, its propagation and reflection during entire loading process. Simulation results yield information on  contact behavior, velocity and deformation of particles during dynamic loading. Effects of shock wave propagation on loading parameters are also discussed. The elasto-plastic shock propagation in granular material has many practical applications including the high-velocity compaction of particulate material.

Place, publisher, year, edition, pages
Hindawi Publishing Corporation, 2011
National Category
Applied Mechanics
Identifiers
urn:nbn:se:kth:diva-31291 (URN)10.1155/2011/123695 (DOI)2-s2.0-80053523297 (ScopusID)
Funder
TrenOp, Transport Research Environment with Novel Perspectives
Note

QC 20110311

Updated from submitted to published 20120120

Available from: 2011-03-11 Created: 2011-03-11 Last updated: 2016-04-28Bibliographically approved
2. Simulating the dynamic loading of non-homogenous spherical particles using discrete element method
Open this publication in new window or tab >>Simulating the dynamic loading of non-homogenous spherical particles using discrete element method
2011 (English)In: Advanced Powder Technology, ISSN 0921-8831, E-ISSN 1568-5527Article in journal (Other academic) Submitted
Abstract [en]

Dynamic loading of a chain of non-homogenous spherical particles is presented by using the discrete element method. The dynamic response of particles is modeled by using elastic and plastic loading, elastic unloading and adhesion at contacts. Of particular interest is to study the transmission and reflection of elasto-plastic shock wave through a chain having; particles of different sizes and materials, voids between the particles and particles with/without adhesion between them. Simulation results yield information on shock propagation, particles velocity and their deformation during dynamic compaction. Particles deformation during normal and reflected shocks, particle velocity fluctuations due to voids between particles and affects of adhesion on particles separation during unloading stage are also simulated.

Keyword
Dynamic compaction; Elasto-plastic shock propagation; Powder processing; particle separation; DEM
National Category
Applied Mechanics
Identifiers
urn:nbn:se:kth:diva-31141 (URN)
Note
QS 20120316Available from: 2011-03-09 Created: 2011-03-09 Last updated: 2012-03-16Bibliographically approved
3. Simulation of high-velocity compaction process with relaxation assists using the discrete element method
Open this publication in new window or tab >>Simulation of high-velocity compaction process with relaxation assists using the discrete element method
2012 (English)In: Powder Technology, ISSN 0032-5910, E-ISSN 1873-328X, Vol. 217, 394-400 p.Article in journal (Refereed) Published
Abstract [en]

The discrete element method is used to investigate the high-velocity compaction process with additional piston supports known as relaxation assists. It is shown that by incorporating the relaxation assists in the piston-die assembly, particles can be better locked during the compaction process. The simulation results reveal that relaxation assists offer; smooth compaction during loading stage, prevention of the particle separation during unloading stage and conversion of higher kinetic energy of hammer into particle deformation. Finally, the influences of various loading elements on compaction process and effects of presence of adhesion during unloading stage are investigated. The results support the findings of experimental work.

Place, publisher, year, edition, pages
Elsevier, 2012
Keyword
High-velocity compaction, Relaxation assist, Discrete element method, Particle separation
National Category
Applied Mechanics
Identifiers
urn:nbn:se:kth:diva-31142 (URN)10.1016/j.powtec.2011.10.054 (DOI)000301159500051 ()2-s2.0-84855211436 (ScopusID)
Funder
TrenOp, Transport Research Environment with Novel Perspectives
Note

QC 20120411

Available from: 2011-03-09 Created: 2011-03-09 Last updated: 2013-04-10Bibliographically approved
4. High-velocity compaction simulation of a two-dimensional assembly of spherical particles using the discrete element method
Open this publication in new window or tab >>High-velocity compaction simulation of a two-dimensional assembly of spherical particles using the discrete element method
(English)In: Advanced Powder Technology, ISSN 0921-8831, E-ISSN 1568-5527Article in journal (Other academic) Submitted
Abstract [en]

High-velocity compaction of a two-dimensional assembly of spherical particles is numerically studied using discrete element simulation. Three particular cases are investigated including closely packed hexagonal assembly, loosely packed random assembly and a non-homogenous assembly of different size and material particles. Primary interest is concerned with linking the particles deformation with the elasto-plastic shock wave. Simulation results yield information on particles deformation during shock propagation and change in overall particles compaction with the velocity of the hammer. The force exerted by particles on the container walls and rearrangement of the loosely packed particles during dynamic loading are also investigated. The effects of presence of friction and adhesion on both overall particles deformation and compaction process are also simulated.

Keyword
High-velocity compaction; Shock propagation; Friction; Particle deformation; Discrete element method
National Category
Applied Mechanics
Identifiers
urn:nbn:se:kth:diva-31143 (URN)
Note

Ingår i avhandling

QS 2015

Available from: 2011-03-09 Created: 2011-03-09 Last updated: 2015-12-14Bibliographically approved

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