Three-dimensional Braided Composites And Multi-scale Numerical Simulation Analysis Of The Interface Failure Criterion

In this paper, three-dimensional braided composite material mainly on two aspects:one is the numerical analysis of circular tubes and multi-scale coupling, two is thestudy of the interface failure criterion. First established in tubular structure of the twomodels, namely the microscopic single cell model and micro fan unit cell model, madeby weaving parameters determining two kinds of structure parameter of the model.,established a fan-shaped periodic unit cell finite element model. Research on how torealize the periodic boundary conditions, the periodic boundary conditions,emphatically discussed the periodic boundary condition in addition. In the periodicboundary conditions, with the master node binding and displacement calculated theaverage stress, strain.In the establishment of the cell model based on circular tube, based on multi-scalecoupling is studied by numerical analysis. In the establishment of the cell model basedon circular tube, based on multi-scale coupling is studied by numerical analysis.Successively via the micro, meso and single cell analysis, obtained the fiber bundles ofthe average of the elastic constants and the average of the elastic constants ofcomposites. Built in two opposite directions of micro fiber stress transfer. Choose arepresentative from the three tube structure with average material parameters and stressanalysis, the results show that: this chapter analysis method, which can calculate thematerial stiffness parameters, and can be used for analysis of injury and strength.Finally, around the three-dimensional braided composite material defect, fibermatrix stress field, under the condition of different defects and interface crack tipsingular stress field expansion. First, we use the relevant theory of fracture, summed upthe three-dimensional braided composite material fracture criterion; Secondly, wecreated two different defect numerical model, on two different defects wereinvestigated by numerical simulation, calculates the corresponding fiber substratebinding sites of stress intensity factor, as well as the crack tip stress intensity factor;Finally, based on the analysis, evaluation of fracture of materials.