CONCERNING THE POLAR DECOMPOSITION OF THE DEFORMATION GRADIENT

For large deformation elastoplasticity, the question of the polar deco mposition of the deformation gradient F is examined. A new decompositi on, involving a triangular matrix S instead of a symmetric matrix U, i s introduced. This paper analyses the properties of the triangular mat rix S and presents the solution for two classical problems concerning the material time derivative of S and the compatibility conditions.