A new integration algorithm for finite strain J2 plasticity based on midpoint rule

Integrating the rate form equations governing the behavior of material isan important step in solving every plasticity problem. providing a compromise betweenaccuracy and computational eort demands the combination of low order elements withecient integration algorithms. first and second order accurate integration algorithmsare well established in the realm of innitesimal theory. however for large deformationplasticity models, second order integration algorithms are not given much attention in theliterature. inspired by midpoint rule algorithms conventionally used in small deformations,a new integration algorithm is proposed for nite strain j2 plasticity that outperformsthe classical backward euler method. algorithmic setup as well as the derivation oftangent operator which is crucial for quadratic rate of convergence of the newton-raphsonalgorithm is discussed in detail. employing four node quadrilateral elements in solvingbenchmark examples it is shown that the proposed algorithm is very stable from numericalstandpoint and has outstanding convergence properties