Reliability Modeling And Analysis Of Composite Laminates

As one of the important materials for mechanical lightweight design,fiber reinforced composites have been widely used in engineering equipment and products.For composite laminates,due to the anisotropy and large performance dispersion of composite materials,it is necessary to consider more random variables in the strength analysis due to many uncertain factors such as load,environment and laminated structure.The performance functions of Tsai-Hill strength criterion,Tsai-Wu strength criterion based on laminated elements are mostly non-linear functions;there are failure correlations between failure elements and failure paths of laminated plates;in addition,the failure process of laminated plates is often accompanied by transfer and redistribution of load.These bring some difficulties to the reliability analysis of composite laminates,and the traditional reliability analysis methods can not effectively solve these problems.Therefore,it is very important to study the reliability analysis method of composite laminates.Firstly,the research progress of reliability analysis of composite laminates at domestic and foreign is introduced.The reliability analysis of composite laminates involves multivariable,non-normal,non-linear performance function and failure correlation,etc.Aiming at analysis problems,universal generating function approach is introduced.Secondly,universal generating function approach is used to describe probability distribution of load,resistance and resistance sequence,by defining relevant compositional operators.By means of the compositional operation of universal generating functions,reliability analysis model of composite laminates is established based on first/last ply failure assumption and Tsai-Hill strength theory.This method can be applied to the reliability analysis of structure systems with many random variables(including non-normal random variables)and the non-linear performance function.Failure correlation between failure paths of laminates due to containing common failure elements and failure correlation within each failure path due to sharing the common random load source are considered by this method.In compositional operations of universal generating functions,K-means clustering and like terms collecting techniques are used to reduce computational costs and the efficiency is dramatically improved.Specific examples are given based on this approach.The Analysis shows that the reliability value of the proposed method is more similar to the Monte Carlo simulation results than that of traditional first order reliability methods.Finally,the tensile test of concrete glass/epoxy resin(1200tex/NPES-901)laminates was carried out,and the material parameters were obtained.Based on the assumption of the first ply failure,the theoretical reliability simulation of laminates with paving angle(90°/0°/90°)is carried out.Under different tensile loads,unidirectional tensile tests were carried out on laminates with laying angles of(90°/0°/90°).The reliability of the tests was compared with the theoretical simulation results,which verifies the accuracy of the method.