The following are some commonly used/suggested optimization problem formulations:
1. Minimize (weighted/total/regional) compliance
With constrained (total/regional) volume/mass fraction
2. Minimize (total/regional) volume/mass fraction
With constrained displacements
3. Maximize (weighted) frequency
With constrained (total/regional) volume/mass fraction
4. Minimize (total/regional) volume/mass fraction
With constrained frequencies
5. Minimize combined compliance and frequencies
With constrained (total/regional) volume/mass fraction
6. Minimize (total/regional) volume/mass fraction
With stress constraints
