Products: ABAQUS/Standard ABAQUS/Explicit
Benefits: The through-thickness modulus is now based on plane stress conditions rather than plane strain conditions. This modification provides more appropriate results for shell-like applications where the thickness direction is unconfined and an increased stable time increment size in ABAQUS/Explicit.
Description: The through-thickness stress resultant is related to an effective thickness direction strain by 
. The resultant modulus in the thickness direction, 
, is now based on plane stress conditions. For an isotropic material the plane stress thickness modulus is
. Using the plane stress thickness modulus is more appropriate for shell-like problems that are free to expand or contract in the thickness direction. Furthermore, incompressible behavior is now allowed, where Poisson’s ratio is 0.5. For analyses in ABAQUS/Explicit where the thickness direction behavior determines the stable time increment size, larger stable time increments will be used, since the thickness modulus is lower by a factor related to Poisson’s ratio.References: