Study On Multi-scale Modeling And Analysis Of Woven Composite Structures

Woven composites have more and more extensive applications because of their excellent mechanical properties.However,the micro-structure of this material is complex,and the macroscopic behavior of the material is usually affected by the fine scale structure,which is difficult to be considered by traditional continuum mechanics.In addition,the description of micro-scale stress and strain by previous multi-scale methods is not accurate enough.Therefore,the analysis method of woven composites needs to be further studied.In this paper,the computational continua multi-scale method(C~2)and the multi-level multi-site mesh refinement model(M~2)for woven composite are proposed.The article is mainly composed of the following three aspects:Firstly,a two-scale model of woven composites was established based on the computational continua equation.Fiber bundles and woven laminates are treated as finescale and coarsescale problems respectively.By assembling finescale computational unit cells(CUC)on each integral point of the coarsescale FEM model,the general solution domain is established.Finescale and coarsescale responses can be calculated by solving one finite element equation.Then,a three-scale model of woven composites was established based on the computational continua equation.The effect of monofilament fibers on the fiber bundle and the whole laminate is considered in this model.The total strain was decomposed into three parts of strain(microscopic,mesoscopic and macroscopic),and the relationship between different scales was established by governing equations.In addition,the multi-scale problem of solid element and third-order shear plate(TOS)element is considered for the two-scale and three-scale C~2 methods,respectively.Finally,a 2-D multilevel multisite mesh refinement analysis model(M~2)is developed for the problem with multiple complex micro-features.On this basis,a three-dimensional M~2method is proposed to analyze the local displacement and stress of woven composite laminates.The fine mesh regions of each scale were regarded as superelements,and their contributions to macroscopic stiffness were included in the total stiffness matrix.The continuity equation is used to ensure the displacement continuity and internal force balance between two interfaces with different scales.This method avoid the requirement of consistency of mesh division between different scales,and which can be used to analyze the woven composite model with large scale effect.The effectiveness of the C~2 and M~2 methods is verified by compare with direct numerical simulation(DNS)model.