In the aircraft industry, mass plays a critical role in deciding aircraft
performance. The amount of lift required increases with the increase of mass,
thereby increasing the drag and thrust on the aircraft. To overcome this, additional
fuel would be needed, which would eventually increase the mass. Thus, it is
important to account for structural mass in an aircraft and optimization is one such
technique that can be used to obtain efficient results for aircraft structures.

Topology Optimization

Topology optimization has been widely used in the aircraft industry because of its
ability to determine the optimized load path with efficient material distribution
and mass reduction. The OptiStruct algorithm alters the
material distribution to optimize the user-defined objective function under given
constraints.

Figure 1 shows the results from the topology
optimization of a helicopter performed in OptiStruct. In
this case, the objective is to minimize mass, with weighted compliance as the
constraint.

Failsafe Topology Optimization

Regular topology optimization runs may not account for the feasibility of design in
situations where a section of the structure fails. Failsafe optimization divides the
structure into damage zones (Figure 2) and generates multiple models
(equal to the number of failure zones), wherein each model is the same as the
original model without one failure zone. In this process, the failsafe topology
optimization is applied by running topology optimization simultaneously for all such
generated models and a final design output which is optimized to account for all
generated models.