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Structural topology optimization of multibody systems

Ghandriz, Toheed; Führer, Claus LU and Elmqvist, Hilding (2016) In Multibody System Dynamics 39(1). p.135-148
Abstract

Flexible multibody dynamics (FMD) has found many applications in control, analysis and design of mechanical systems. FMD together with the theory of structural optimization can be used for designing multibody systems with bodies which are lighter, but stronger. Topology optimization of static structures is an active research topic in structural mechanics. However, the extension to the dynamic case is less investigated as one has to face serious numerical difficulties. One way of extending static structural topology optimization to topology optimization of dynamic flexible multibody system with large rotational and transitional motion is investigated in this paper. The optimization can be performed simultaneously on all flexible bodies.... (More)

Flexible multibody dynamics (FMD) has found many applications in control, analysis and design of mechanical systems. FMD together with the theory of structural optimization can be used for designing multibody systems with bodies which are lighter, but stronger. Topology optimization of static structures is an active research topic in structural mechanics. However, the extension to the dynamic case is less investigated as one has to face serious numerical difficulties. One way of extending static structural topology optimization to topology optimization of dynamic flexible multibody system with large rotational and transitional motion is investigated in this paper. The optimization can be performed simultaneously on all flexible bodies. The simulation part of optimization is based on an FEM approach together with modal reduction. The resulting nonlinear differential-algebraic systems are solved with the error controlled integrator IDA (Sundials) wrapped into Python environment by Assimulo (Andersson et al. in Math. Comput. Simul. 116(0):26–43, 2015). A modified formulation of solid isotropic material with penalization (SIMP) method is suggested to avoid numerical instabilities and convergence failures of the optimizer. Sensitivity analysis is central in structural optimization. The sensitivities are approximated to circumvent the expensive calculations. The provided examples show that the method is indeed suitable for optimizing a wide range of multibody systems. Standard SIMP method in structural topology optimization suggests stiffness penalization. To overcome the problem of instabilities and mesh distortion in the dynamic case we consider here additionally element mass penalization.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Flexible multibody dynamics, SIMP, Structural topology optimization, Transient response
in
Multibody System Dynamics
volume
39
issue
1
pages
14 pages
publisher
Springer
external identifiers
  • scopus:84988693272
  • wos:000390126700009
ISSN
1384-5640
DOI
10.1007/s11044-016-9542-7
language
English
LU publication?
yes
id
60682952-2ffd-4b44-820c-f3072ec90f29
date added to LUP
2016-10-31 15:27:30
date last changed
2017-09-18 11:28:52
@article{60682952-2ffd-4b44-820c-f3072ec90f29,
  abstract     = {<p>Flexible multibody dynamics (FMD) has found many applications in control, analysis and design of mechanical systems. FMD together with the theory of structural optimization can be used for designing multibody systems with bodies which are lighter, but stronger. Topology optimization of static structures is an active research topic in structural mechanics. However, the extension to the dynamic case is less investigated as one has to face serious numerical difficulties. One way of extending static structural topology optimization to topology optimization of dynamic flexible multibody system with large rotational and transitional motion is investigated in this paper. The optimization can be performed simultaneously on all flexible bodies. The simulation part of optimization is based on an FEM approach together with modal reduction. The resulting nonlinear differential-algebraic systems are solved with the error controlled integrator IDA (Sundials) wrapped into Python environment by Assimulo (Andersson et al. in Math. Comput. Simul. 116(0):26–43, 2015). A modified formulation of solid isotropic material with penalization (SIMP) method is suggested to avoid numerical instabilities and convergence failures of the optimizer. Sensitivity analysis is central in structural optimization. The sensitivities are approximated to circumvent the expensive calculations. The provided examples show that the method is indeed suitable for optimizing a wide range of multibody systems. Standard SIMP method in structural topology optimization suggests stiffness penalization. To overcome the problem of instabilities and mesh distortion in the dynamic case we consider here additionally element mass penalization.</p>},
  author       = {Ghandriz, Toheed and Führer, Claus and Elmqvist, Hilding},
  issn         = {1384-5640},
  keyword      = {Flexible multibody dynamics,SIMP,Structural topology optimization,Transient response},
  language     = {eng},
  month        = {09},
  number       = {1},
  pages        = {135--148},
  publisher    = {Springer},
  series       = {Multibody System Dynamics},
  title        = {Structural topology optimization of multibody systems},
  url          = {http://dx.doi.org/10.1007/s11044-016-9542-7},
  volume       = {39},
  year         = {2016},
}