A large strain explicit formulation for composites

A geometrically non-linear formulation for composites and the resulting exp licit dynamic finite element algorithm are presented. The proposed formulat ion assumes that small elastic and large plastic strains, being the anisotr opy considered using tensors which map the model variables at each time ste p into an equivalent isotropic space, where the integration of the rate con stitutive equations is performed. The evolution of the internal variables i s calculated in the auxiliary spaces, taking into account the material non- linear behaviour, and the results mapped back to the real stress space. The updating of the mapping tensors for each new spatial configuration allows the treatment of general anisotropic materials under large strain and can b e extended to treat multiphase composite materials using the mixing theory. The behaviour of the composite is dictated by the mechanical response of e ach substance, and the resultant model allows a fully non-linear analysis c ombining different material models, such as damage in one compounding subst ance, elastoplastic behaviour in the other, while a third substance behaves elastically. Copyright (C) 1999 John Wiley & Sons, Ltd.