In ANSYS 12.0.1, it’s useful to note two important changes to the INTER19x gasket elements:

  • Inclusion of transverse shear stiffness is default behavior (KEYOPT(2))
  • For higher-order elements, full integration is default (KEYOPT(4))

Gasket elements have complex compressive behavior, where the user can define the compression pressure-closure relationship, along with either linear or nonlinear unloading. Because gasket materials are meant to represent complex compressive behavior, the tensile or transverse stiffnesses are assumed to be small or negligible. In ANSYS 11.0 and prior, tensile and transverse shear stiffness were, by default, set to zero. This was problematic for users who used contact elements between the gasket and other parts since transverse shear stiffness, by default, was zero, which produced a numerical singularity. Although input of tensile and transverse shear stiffness were available in ANSYS 11.0 and prior, not many users realized the importance of these parameters, especially in cases of contact.

In ANSYS 12.0.1, transverse shear stiffness is included by default (unless KEYOPT(2) is explicitly set to zero), and if the user does not specify a value via TB,GASKET,,,,TSS command, 0.5% of the initial compressive slope is used.

Please note that the tensile stiffness and the tensile cap (TB,GASKET,,,PARA) are still assumed to be zero by default.