Research On Equivalent And Optimization Approach For Thick Composite Laminates

With the improvement of manufacturing technology and enhancement of structure design ability,there is a transition for the application of composites on aircraft from secondary load-carrying components to main load-carrying components.Hence it is necessary to introduce thick composite laminates.Using existing modeling method,the analysis of thick laminates are extremely timeconsuming due to their large scale in finite element model.Therefore,quick analysis and optimization approaches for thick composite laminates have been addressed in engineering.Nowadays research on quick analysis of thick laminates is based on the theory of three-dimensional effective elastic constants.Typical sublaminate is studied and equivalent homogeneous anisotropic solids are used to represent thick laminates in this theory.However,the determination of typical sublaminate is not clear and there is no good optimization approach for thick laminates.In this paper,thick composite laminates are studied based on the theory of three-dimensional effective elastic constants.Numerical simulation and experiments are carried out.The determination of typical sublaminate and calculation accuracy of interlaminar stress in equivalent model are studied through numerical simulation of thick rectangle cantilever beam and thick laminates under three-point bending.Experiments of thick laminates subjected to three-point bending were performed to obtain the mechanical behavior of specimen.Numerical simulation of specimen are conducted and numerical results are compared with experimental results to study the applicability of equivalent model further.Considering laminate stiffness and interlaminar strength,an optimization approach for thick laminates is proposed integrating Isight,Matlab and MSC.Patran/Nastran.This approach is proved to be feasible through quadrilateral simply supported thick laminate and thick-walled cantilever tube.