Hyperelastic Model with Energy Limiter for EPDM and Its Numerical Application

To simulate the working process of EPDM PSD of dual-pulse solid rocket motor from beginning to failure, we use a hyperelastic model with erergy limiter to model this working process. In traditional practice, the consistent tangent moduli of mechanical model is derived by analytic method, however, the analytic method is tedious and fallible. To solve this problem, we introduce numerical approximate method (complex-step derivative, which is proved to be of second-order for suitably small perturbation and does not suffer from inherent subtractive cancellations ) to derive the consistent tangent moduli, which is simple, robust, and efficient, and can be easily implemented into commercial finite element software. Finally, we simulate a case of unixial tension of a dumbbell-shape and compare the simulation results with the analytic results, a good agreement between the two kinds of results is observed.