An efficient iteration-free numerical scheme for finite element simulations employing pressure-dependent elastoplasticity using paraboloidal yield criterion

An in-depth understanding of the non-linear mechanical response of polymer is essential for the constitutive modelling in the micro-mechanical simulation of fibre-reinforced polymer (FRP) composites. The plasticity behaviour of the polymer matrix combines distortional and spherical energy dissipation. A thermodynamically consistent, elastoplastic continuum model is proposed using the paraboloidal yield criterion under isothermal conditions. A non-iterative scheme is developed for the numerical computation of the plastic strain increment multiplier. Both associated and non-associated flow rules are investigated following classical plasticity loading-unloading conditions. The conventional computationally demanding iterative scheme is replaced with an exact plastic strain increment value, thus improving the computational efficiency. Coupon-sized numerical models are investigated, and the comparison between simulated and experimental results shows unprecedented accuracy of the proposed elastoplastic mathematical model