D3PLOT 22.1

Out of Plane (Z') Stress Tensor Components

Out of plane (Z') stress tensor components

Depending on their element formulation (elform on *SECTION_TSHELL) thick shells in Ansys LS-DYNA may or may not calculate the element through-thickness ( ZZ' ) direct stress.

  • Elform 1 (single point) and 2 (reduced 2x2 point) integration schemes are effectively extruded thin shells and do not calculate ZZ' which will always be zero.
  • Elforms 3 onwards are closer to bricks than shells and develop a full 3d stress state, so ZZ' is computed.

The through thickness shear terms ( YZ' and XZ' ) are calculated in all cases (just like thin shells).

Thus the local stress tensor will be one of

For shell-like formulations

For brick-like formulations.

This means that principal stresses will not necessarily lie in the plane of the shell.