For SURF151, SURF152, SURF153, and SURF154, the seventh real constant (TKI, the thickness at node I) takes a value of 0.0 rather than the former value of 1.0 if that constant is input as zero or blank. The new default value may affect the volume and mass of the indicated surface elements.

For SURF151 and SURF152, the change may also affect the element heat generation and specific heat logic. For SURF153 and SURF154, the change may also affect the surface-tension logic.

In previous releases, Mechanical APDL performed byte-swapping on most Windows and Linux platforms before writing any file data or after reading any file data; byte-swapping was not performed on most UNIX platforms.

To improve performance, byte-swapping is no longer performed on Windows and Linux platforms at this release, but is performed on most UNIX platforms.

This incompatibility affects only third parties who interface with ANSYS binary files (that is, read/write ANSYS binary files in their own programs). Affected third parties must modify their code to accommodate this change.

BINLIB and the demonstration routines provided with the release (documented in the Programmer's Manual) have been upgraded to reflect this change, and can read either format.

The results file has the following new or changed records (as documented in the Programmer's Manual):

The results file access routines provided with the release (also documented in the Programmer's Manual) have been upgraded to reflect this change, and can read current results files as well as files from prior releases.

Spin softening is now activated by default in prestressed modal analyses when any rotational velocities are specified. If you did not explicitly request it in prior releases, you may notice different frequencies.

Defining an ocean environment using non-table data has changed slightly when the specified ocean data type is “wave” (OCTYPE,,WAVE). Valid wave-theory values for specifying the API (for computing particle velocities and accelerations due to waves and current) have been changed from 10+ to 101+, as follows:

An option (TBOPT) on the TB,RATE command has changed. The former TBOPT = CHABOCHE option is now TBOPT = EVH. The option offers exponential visco-hardening with nonlinear kinematic hardening using von Mises or Hill plasticity. Specify this option as follows: TB,RATE,,,6,EVH

The mass inertia contributions to rotational degrees of freedom are now considered when using the lumped matrix formulation (LUMPM,ON) with element types BEAM188, BEAM189, PIPE288, PIPE289, SHELL181, and SHELL281. This change means that you can now account for dynamic torsional effects for beams or pipes in your analysis when using the LUMPM,ON command. Accuracy may be affected by a small amount.

The contacting area output quantity CAREA is now reported as a single-valued element quantity for contact elements CONTA171 through CONTA177. Individual nodal quantities for CAREA are no longer reported.