Multi-Step Optimization Method Of The Thick Composite Laminate Structures Considering Inter-laminar Stresses

With the improvement of structural design level and the rapid development of manufacturing technology,the thick composite laminate structure has been widely used in the field of aeronautics and astronautics.To give full play to the utilization of composite materials and reduce the structural weight,it is necessary to optimize the thick composite laminate structure.Many scholars at home and abroad have made a deep research on the optimization design of thin-walled composite structure,and achieved remarkable results.However,there are few researches on the optimization design of thick composite laminate structure.Therefore,it is very important to study an effective optimization design method to realize the initial design of thick composite laminate structure.In this paper,the finite element modeling method based on the sublaminate partitioning element is studied for the thick composite laminate structure firstly.Through examples of a thick composite tube with internal pressure and thick laminates under three-point bending,the validity of the finite element analysis method based on the sublaminate partitioning element is validated in solving the three-dimensional stress problem of thick composite laminate structure.Secondly,considering the in-plane stress constraint,the inter-laminar stress constraint and the technological requirements,a multi-step optimization design method based on sub-laminated finite element model is proposed in this paper for the thick composite laminate structure consisting of a repeating sub-laminate.According to different design variables,the optimization process is decomposed into several steps,which can optimize the number of plies in the sub-laminate,the number of sub-laminates,the ply volume proportions and the stacking sequence,and then achieve the aim of reducing the structural mass.Finally,Matlab is adopted to program the genetic algorithm,and the Isight optimization design platform integrated Matlab and Abaqus is utilized to achieve this multi-step optimization method.The effectiveness of multi-step optimization design is proved through the optimization of the thick composite tube,three-point bending thick plate and an all-moved wing pivot.This optimization method provides the idea for the initial design of thick composite laminate structure,and has an important practical value in engineering.