engleski

On the increase of computational algorithm efficiency for elasto-plastic shell analysis

A robust and unconditionally stable return mapping algorithm based on the discrete counterpart of the principle of maximum plastic dissipation is presented. The explicit expression for the consistent elastoplastic tangent moduli is developed. All expressions are derived via tensor formulation showing the advantage over the classical matrix notation. The integration algorithm is implemented in the formulation of the four-node isoparametric assumed-strain finite-rotation shell element employing Mindlin-Reissner type shell model. A layered model applied enables the exhibiting of plastic zones through the shell thickness. Material nonlinearity described by von Mises yield criterion and isotropic hardening is combined with geometrically nonlinear response assuming finite rotations. The efficiency of the present formulation in conjunction with the standard Newton iteration approach, where no line search procedures are required, is illustrated by numerical examples. The excellent performance of the algorithm for large time resp. load steps is demonstrated.

Assumed strain finite element; consistent tangent modulus; elastoplastic analysis; finite rotation; integration algorithm; shell structures

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