macopt#

SpecialPurpose.macopt(**kwargs)#

Specifies modal assurance criterion (MAC) or frequency response function (FRF) correlation criteria calculation options for rstmac.

Mechanical APDL Command: MACOPT

Command default: If macopt is not issued prior to rstmac, node matching based on location is used by default in MAC calculations performed by rstmac. Unless otherwise specified, an absolute tolerance (ABSTOLN) value of 0.01 is used for the node matching.

Notes

The rstmac command calculates the MAC or FRF criteria values based on the options specified via macopt. The macopt command must be issued before the rstmac command. These commands enable you to compare nodal solutions from two results files ( .rst or .rstp ) or from one results file and one Universal Format file ( .unv ). Multiple macopt commands can be issued to specify which results are compared and how.

As listed in the table above, model solutions can be compared using three different mehtods: matching nodes based on location, matching nodes based on node number, or by node mapping and solution interpolation.

When node mapping and solution interpolation is performed ( Option = NODMAP), the following applies:

  • File1 on rstmac must correspond to a model meshed in solid and/or shell elements. Other types of elements can be present, but the node mapping is not performed for these elements.

  • You should only compare solutions of models having the same dimension (both models are 2D or both models are 3D). Comparing models with different dimensions may lead to incorrect results if the solution at mapped/matched nodes is not representative of the global solution.

  • Interpolation is performed on UX, UY, and UZ degrees of freedom.

Node pair MAC computation ( Option = NMAC) is only supported when a matching procedure is used and a specific substep number is requested for each solution ( Sbstep1, Sbstep2 on rstmac command).

Non-structural degrees of freedom in coupled-field analyses are supported for the matching methods ( Option = ABSTOLN or NUMMATCH). Multiple macopt, DOF commands can be issued consecutively to combine different degrees of freedom.

The FRF option is not compatible with any MAC calculation options (DOF, NMAC and KEYMASS) and can only be used with node matching procedures.

Example Usage

For a detailed discussion on using macopt with examples, see Comparing Nodal Solutions From Two Models or From One Model and Experimental Data (RSTMAC)