Uncertain Parameter Identification Of Composite Materials Based On Random Substructure

Due to the complexity of the weaving process and the differences in the production process,the composites has many uncertainties.In order to obtain an accurate composite material dynamic model,it is necessary to fully consider the non-uniformity and randomness of the composites structure parameters.Therefore,research and development of uncertainty parameter identification methods for composites has become an inherent requirement of modern engineering science.This paper focuses on three aspects of research on the identification method of uncertain parameters of composites:Firstly,the elastic parameter field of uncertain materials for composites is developed.Based on K-L series,the elastic parameter field of the composites is expanded,a random field description method based on polynomial chaos expansion is proposed,and the influence of the elastic parameter correlation of the composites on the dynamic characteristics is studied.The proposed method can be used for dynamic analysis of the coexistence of uncertainty and nonuniformity in the spatial distribution of composites.Secondly,a dynamic forward problem research of composites based on the substructure theory is carried out.Providing a method basis for the efficient calculation of the iterative process of uncertainty parameter identification.Aiming at composite unit cells,a repetitive substructure model is proposed to verify the superiority of the substructure method in simplifying modeling and improving calculation efficiency.For uncertain composites,a random substructure model is proposed to improve the computational efficiency of the analysis of uncertain dynamic characteristics of composites.Finally,in order to solve the problem of difficulty in identifying uncertain parameters of composites,a method for identifying uncertain parameters based on response surface is proposed.Aiming at the probability distribution characteristics of uncertain parameters,the identification of uncertain parameters based on random response surface and interval orthogonal expansion is carried out separately.Avoiding the solution of complex random sensitivity matrix.Through step-by-step correction,it is easier to realize the identification of uncertain parameters of composites.