| As an efficient optimal structure method,topology optimization method is a method to find the optimal distribution of material in a given continuous design domain under some constraints(e.g.stress,displacement,or volume of material),which makes some performance(e.g.minimum compliance)of structure reach the best.In this work,the purpose is to search for the differences of the optimal result of the structure applied with pressure loads made by laminate composites and study the topology optimization design of underwater pressure structure with orthotropic material.The research of this work is carried out by defining the topology objective,establishing mathematical model and applying the SIMP method to the process of topology optimization.In the design case of underwater pressure structure,the pressure loads applied on the boundary of structure is never fixed but design dependent.As a result,an important step of topology optimization is to define the changing pressure loading surface.The fundamentals of the DRLSE method and isoline method are introduced as two kinds of image segmentation technique and the isoline method is selected as a main boundary searching method in this work after comparing the two methods.In order to prevent from some numerical problems(e.g.checkerboard pattern,porous material),four sensitivity filtering methods are introduced and applied to the calculation of topology model.At last,a new element stiffness matrix is derived for the topology optimization with composite material and orthotropic material.Three numerical cases are calculated and analyzed,which are the design cases of bridge-like structure with laminate composites,underwater structure subjected to hydrostatic pressure with orthotropic material,orthotropic underwater structure with initial void and inside simplysupported constraints,respectively.The topology optimization method used in this work is identified.And the influence on the optimal topology structure induced by laminate composites and orthotropic material is discussed,which may make a lot contribution to the study of new kind of underwater pressure structure. |
