Problem: When trying to do the topology optimization for a part, and if some regions are not required to be optimized (material removal is not expected), but Discovery Explore does not retain it and it tries to optimize based on the constraining conditions provided.

For a scenario with a downward acting force of 1000N on the A-arm, the middle connecting portion (highlighted in orange) is required to be retained after optimization. The force application and the middle portion highlighted is as shown below,

After the topology optimization, the optimized shape looks as shown below, where the material in the middle connecting portion in the A-arm is removed.

Causes: There is no input provided which enables the software to exclude the region from topology optimization.

Workarounds:  There is no standard feature to exclude regions from optimization studies, although there are workarounds to do so.

• Applying small pressure on the faces that are to be retained.

If a small (close to 0 Pa) pressure is applied on the faces, the software excludes the volume to a thickness of protected distance specified, and the region is excluded from the topology optimization.

• Applying dummy displacement boundary conditions with all DOFs free on the faces that are to be retained.

If a dummy displacement boundary condition with all DOFs free is applied on the faces, the software will exclude the volume till a thickness of protected distance specified, and the region is excluded from the topology optimization.

• Applying dummy mass of 0kg on the faces that are to be retained.

If the simulation includes gravity effect, a zero kg mass can also be applied to the faces that are to be retained.