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Optimal cross-section and configuration design of cyclic loaded elastic-plastic structures

  • Valido, Anibal J. (Escola Superior de Tecnologia, Instituto Politecnino de Setubal Rua do Vale de Chaves) ;
  • Sousa, Luis G. (Instituto Superior Tecnico, Universidade Tecnica de Lisboa Av.) ;
  • Cardoso, J. Barradas (Instituto Superior Tecnico, Universidade Tecnica de Lisboa Av.)
  • Published : 1996.01.25

Abstract

This paper describes a continuum variational formulation for design optimization of nonlinear structures in the elastic-plastic domain, where unloading and reloading of the structures are allowed to occur. The Total Lagrangian procedure is used for the description of the structural deformation. The direct differentiation approach is used to derive the sensitivities of the various structural response measures with respect to the design parameters. Since the material goes into the inelastic range and unloading and reloading of the structure are allowed to occur, the structural response is path dependent and an additional step is needed to integrate the constitutive equations. It can be shown, consequently, that design sensitivity analysis is also path-dependent. The theory has been discretized by the finite element technique and implemented in a structural analysis code. Mathematical programming approach is used for the optimization process. Numerical applications on trusses are performed, where cross-sectional areas and nodal point coordinates are treated as design variables. Optimal designs have been obtained and compared by using two different strategies: a two level strategy where the levels are defined accordingly the type of design variables, cross sectional areas or node coordinates, and optimizing simultaneously with respect to both types of design variables.

Keywords

References

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  2. Design sensitivity and finite element analysis of free surface flows with application to optimal design of casting rigging systems vol.28, pp.3, 1998, https://doi.org/10.1002/(SICI)1097-0363(19980915)28:3<419::AID-FLD721>3.0.CO;2-4
  3. Optimal cross-section and configuration design of elastic-plastic structures subject to dynamic cyclic loading vol.13, pp.2-3, 1997, https://doi.org/10.1007/BF01199229
  4. Optimal design of elastic-plastic structures with post-critical behaviour vol.17, pp.2-3, 1999, https://doi.org/10.1007/BF01195939