LAUSR

Abstract Although the Hughes-Winget rotation tensor is not strongly objective when stretching occurs during a time step it is very accurate when the incremental stretching during the time step is small, a condition that is almost always met in practice. Two types of evolution equations based on the Jaumann derivative are examined which show that the main source of error in the numerical algorithms is due to the approximation of the average deformation rate during the time step. A new strongly objective expression for the average deformation rate during a time step is developed and shown to correct the observed errors in tests of strong objectivity.