International Research Center for Computational Mechanics学术报告
报告题目： Topology optimization of non-linear materials and structure
In this talk, examples of methods and algorithms for non-linear topology optimization will be discussed. In the first example, a dynamic finite strain visco-plastic model that is implemented in a gradient based topology optimization framework to design impact mitigating structures will be presented. The kinematics relies on the multiplicative split of the deformation gradient, and the constitutive model is based on isotropic hardening viscoplasticity. To solve the dynamic mechanical balance laws the implicit Newmark-beta method is used together with a total Lagrangian finite element formulation. The optimization problem is regularized using a partial differential equation filter and solved using the method of moving asymptotes (MMA). Sensitivities required to form the MMA approximation are derived using the adjoint method. In the second part of the talk optimal design of micro-structures will be discussed. Structures that are optimized for maximal negative Poisson’s ratio will be presented. It will be shown that the problem of minimizing the Poisson’s ratio of a material shares many features with the problem of maximizing the tangent-stiffness of structures. In the last example, we will address the problem of designing micro-structures that are able to dissipate a large amount of energy during large deformations.
Introduction of ProfessorMathias Wallin：
Professor Mathias Wallin is head of the division of Solid Mechanics in Lund since Jan. 1 2016. Prof. Wallin has conducted research in materials modeling (metals, fibrous based material, polymers), numerical methods and structural optimization. He has received several prestigious grantsfrom the Swedish research council and Crafoord foundation related to modeling of polymers, metalsand recently a project that aims at designing materials at the microlevel using optimizationtechniques. Wallin has also been the principal investigator of industry funded project (TetraPak)where the aim is to increase the understanding of the deformation mechanisms in packagingmaterial. Wallin has been the director of studies at Solid mechanics for several years and iscurrently also the director of the Engineering physics program at LTH.