Stress recovery for solids uses the jacobian at the corners of the element, but element generation uses the jacobian at the gauss point and never checks at the corners. This means that for some elements the gauss point can have a positive jacobian but the corner can have a negative jacobian, causing stress recovery to fail unexpectedly.
Fix is to either not bail in JAC3D, or to recover stress at the gauss point and extrapolate to the corners, or to check the corners in element generation so the failure happens early.
This is reproduced by the MacNeal-Harder 3d solid patch test, which is now in the validation set.
Stress recovery for solids uses the jacobian at the corners of the element, but element generation uses the jacobian at the gauss point and never checks at the corners. This means that for some elements the gauss point can have a positive jacobian but the corner can have a negative jacobian, causing stress recovery to fail unexpectedly.
Fix is to either not bail in JAC3D, or to recover stress at the gauss point and extrapolate to the corners, or to check the corners in element generation so the failure happens early.
This is reproduced by the MacNeal-Harder 3d solid patch test, which is now in the validation set.