Progressive damage analysis method and experimental investigation of composite end frame structure

Aiming at the upper and lower end frames of the grid stiffened composite cylinder, the tensile tests of three kinds of end frame segment models with different sizes and stacking sequence were conducted. Thus the damage forms and ultimate load of the end frames were gained. The progressive damage analysis based on various strength theories was conducted by finite element method, and the results of different theories were compared. Based on Zinoviev strength theory, by expanding its failure criterion and stiffness degradation scheme to three-dimensional format, and introducing Hashin criterion to estimate the damage modes, the modified Zinoviev theory was developed. The proposed method was used to carry out damage evolution analysis and strength prediction of the end frame model. The results of numerical simulation show good agreement with test results.