The Critical Load Forecasting And Fatigue Propetties Of Hybrid Bi-stable Laminate

A bi-stable laminate is a laminate that has two stable configurations,there is a big different between these two configurations. Each stable configuration has a certain ability of bearing load,and it can maintain its configuration without the help of external energy or load.These two configurations can mutual be converted with the proper external load.For these characteristics of bi-stable laminate,the prospects in the application on the field of aerospace and energy collecting will be worth looking forward.The metal hybrid bi-stable laminate is a laminate that metal and composite are hybrid overlayed.It will be more designable and has a better ability to maintain configurations than ordinary bi-stable laminate.These advantages will be more valuable in future applications.The Rayleigh Ritz method were used to establish the configurations of metal hybrid bi-stable laminate in low order and high order.The results of the two models are compared with the experimental values, and the higher order model is more accurate in the prediction of the configurations.The reason why the higher order model is more accurate than the low order model was analysised and the method to improve the accuracy of the model was also be proposed.On the basis of the high order configurations prediction model, an analytical model for predicting the critical load is established.Theoretical model after all has limitations in assuming the out-plane displacement function and inplane strain function,so the finite element method to solve curvature and the critical load of the laminate were studied, in order to eliminate this limitation and to make the result more accurate.Compared with the experimental results, the results of finite element analysis and experimental results are compared with the experimental results. The research show that the finite element method is closer to the experimental results.Then based on the finite element method, the influence of dimension parameters, material parameters, composite material and metal thickness ratio on the curvature and the critical load were studied.Finally, this article has carried on the fatigue test of metal hybrid laminates, fitting the critical load changes with the number of cycles.Then from assumptions of material properties parameters attenuation and the matrix creep to find the reason why the critical load drops.In this paper, the creep model and the finite element method are used to explain the attenuation range of the critical load, and the corresponding verification is carried out.