Research On Explicit Topology Optimization Considering Composite Structure

Topology optimization,aiming at optimally distributing a certain amount of materials within a design domain for achieving optimized properties/functions,has demonstrated its effectiveness for structural design and received great increasing research attention in recent years.In order to obtain better structural performance,structural optimization design of multi-layer and multi-material has been widely concerned,such as rib-stiffened structure and multi-type structural combination.In response to these problems,many scholars have carried out a lot of research work.Nonetheless,there are some challenging issues which inevitably confine the implicit topology optimization framework from being widely applied.For instance,there are no way to directly extract the geometric information corresponding to the optimal structure;Besides,the number of design variables depends on the finite element(FE)mesh;Meanwhile,the computational burden is huge especially for three-dimensional problems.In the face of these problems,the explicit topology description framework selected is supposed to provide a more straightforward solution.Under moving morphable component(MMC)framework,design variables are merely the explicit geometric parameters of a components and they are not related to gird density in finite elements method during analysis process,thus,the number of design variables is greatly reduced compared with the traditional implicit topology optimization approaches.Besides by conveniently controlling the geometry,an optimal result satisfying various constraints can be obtained.Furthermore,the explicit geometric boundary information enables the optimal structure to be directly imported into the CAD/CAE system which therefore shows great potential to solve numerous perplexing problems in practical engineering cases.First,this paper presents a Moving Morphable Component(MMC)-based approach for topology optimization of rib-stiffened structures,where the topology and geometry of stiffening ribs are explicitly described.The proposed approach shows several prominent advantages: both the numbers of design variables and degree of freedom(DOF)in FEA are reduced substantially.Also,the proper manufacture-related geometry requirements of stiffening ribs can be readily satisfied without introducing any additional constraint.Meanwhile,the efficiency of the proposed approach is further illustrated with numerical examples on topology optimization of rib-stiffened structures with buckling constraints.Second,considering the characteristics of explicit topology optimization frameworks that its complete decoupling between the geometric model and the finite element model,the present study introduces an optimization methods for composite structure(truss structure and solid structure).The topology optimization of the composite structure comprised of different types of material is realized by the superposition of the stiffness on the background mesh.Contrast to the traditional topology optimization methods,the presented approach is more direct and effective,which means the structural size,shape and topology of two types of material can be optimized synchronously.This paper demonstrates the effectiveness of the proposed method through detailed theoretical derivation and related numerical examples.The research in this paper shows that the movable deformation component method based on the explicit framework has great application scope and application value due to its many advantages.