Source model preparation
Guidelines

An optimization-capable FEA model is prepared essentially in a similar way as an usual FEA model. However, there are some important issues that require careful consideration if topology optimization is planned. Most of all:

• the model must be adequately partitioned into volume and surface regions and
• special situations must be modeled more carefully than this is required for usual FEA.

Domain partitioning

Partitioning into regions is required because volume and surface regions have to be referred to when:

• setting optimization region types (free, fixed, ...),
• assigning special materials (semi-contact, ...),
• assigning design configurators (lattice, shell, ...), and
• imposing technological constraints (unidirectional opening, symmetry, ...).

IMPORTANT. Carefully consider how to partition the domain of your part into volume and surface regions.

Special situations modeling

Special situations like bolt fastenings or pin contacts must be modeled much more carefully than in usual FEA. This is because topology optimization removes material and fully adapts the structural design to the underlying stress field. Consequently, each inaccuracy can be very negatively reflected in the final design. If this happens, the final design can end up being very far from the actually optimal one and the whole procedure can do more harm than good.

IMPORTANT. Carefully analyze your special situations and model these as precisely as possible.

According to this, the process of source model preparation can be outlined as follows.

CAD model preparation

Prepare the CAD model of the considered part by keeping in mind all future

• volume regions and
• surface regions

Figure. Prepare the CAD model with future volume and surface regions in mind.

FEA model preparation

Assign a distinguished material to each individual volume region. ProTOp will recognize this region on the basis of the assigned material.

Figure. Assign different materials to volume regions to expose these regions to ProTOp.

Assign a distinguished fictive surface load to each individual surface region. ProTOp will recognize this region on the basis of the assigned fictive load.

Carefully analyze and model:

• all special situations (like bolt fastenings) and
• structural boundary conditions (supports and loads).

Choose the most appropriate finite element and mesh the domain as uniformly as possible.

Figure. Carefully model all special situations and boundary conditions and mesh the domain.

NOTE. The source FEA model prepared in this way should be ready for import into ProTOp and further optimization task processing.