In the present work, an elasto-plastic model is proposed for the numerical analysis of dynamic nonlinear behavior of composite thick shells with reinforcements in spirals subjected to impulsive loading. Wilkins algorithm was taken to analysis physical and geometrical non-linearity of stress-strain state of elasto-plastic thick composite shells. This study is carried out on two types of cylindrical composite shells in different reinforcement winding angles and different magnitudes of impulse loads. By a calculation code in finite difference, first the influence of physical non linearity on the stress-strain state of cylindrical monolayer shell was established and then the relationship between residual strains and the winding angle of the symmetric reinforcements was investigated. Finally, the influence of the winding angle of the orthogonal reinforcements on the residual strains of a bilayer composite shell was analyzed numerically.

This work is devoted to the experimental study of a glass/polyester composite laminate under impact shock. Based on a thermodynamic approach, the objective is the evaluation of specific interlaminar delamination energy in a multi-layer composite material under impact loading causing damage to it by cracking. For modeling impact loading, it is used an experimental device based on the principle of Charpy test which is to measure residual energy of a mass movement following a shock at speeds generally between 1 and 4 m/s, on a test piece cut of standardized dimensions requested in bending. Some of available energy is consumed by the rupture of the test piece. The results of this work showed that for impact test, mode I fracture energy is function of impact speed and the load fall energy. These results could be useful in the design of multilayer structures in composite materials subjected to impact loads.