Remarks for Sensitivity-Based Optimizations

Within this section some remarks concerning sensitivity based optimization are summarized.

Prescribed Accelerations for Sensitivity-Based Topology Optimization

Prescribed acceleration loading are often caused by gravity fields, centrifugal loading and rotary acceleration loads. This chapter defines which kinds of acceleration types for the MSC Nastran® are feasible for sensitivity-based topology optimization.

The following commands are supported for acceleration loading:

  • GRAV: Defines acceleration vectors for gravity or other acceleration loading.
  • RFORCE: Defines a static loading condition due to an angular velocity and/or acceleration.
  • ACCEL1: Defines static acceleration loads at individual GRID points.

The following are not supported:

  • ACCEL: Defines static acceleration loads, which may vary over a region of the structural model. The load variation is based upon the tabular input defined on this Bulk Data entry.
  • DMIG,UACCEL: Defines rigid body accelerations in the basic coordinate system.

Remarks

  • ACCEL and ACCEL1 may not be available in all versions of MSC Nastran®.
  • Default in Nastran is to apply lumped mass matrices.
  • Applying lumped mass matrices can be enforced using PARAM,COUPMASS,-1
  • Applying consistent mass matrices can be enforced using PARAM,COUPMASS,1
  • SIMULIA Tosca Structure only reads PARAM,COUPMASS for indicating if lumped mass matrices or consistent mass matrices are applied. Consequently, if the METHOD card for RFORCE is applied then the METHOD card should correspond to the mass element type chosen in PARAM,COUPMASS.