7th March 2016
Size optimization defines ideal component parameters, such as material values, cross-section dimensions and thicknesses. Shape optimization is different from freeform (topology) optimization in that it is used once the component’s topology has already been defined. Topology optimization is used to generate material layout concepts whereas shape optimization refines and improves the topology within the concept.
In shape optimization, the outer boundary of the structure is modified to solve the optimization problem. Using finite element models, the shape is defined by the grid point locations. Hence, shape modifications change those locations.
Free-shape optimization uses a proprietary optimization technique developed by Altair Engineering Inc., wherein the outer boundary of a structure is altered to meet with pre-defined objectives and constraints. The essential idea of free-shape optimization, and where it differs from other shape optimization techniques, is that the allowable movement of the outer boundary is automatically determined, thus relieving users of the burden of defining shape perturbations.
Topography optimization generates an optimized distribution of shape based reinforcements such as stamped beads in shell structures. It is an advanced form of shape optimization in which a design region for a given part is defined and a pattern of shape variable-based reinforcements within that region is generated. The approach in topography optimization is similar to the approach used in topology optimization, except that shape variables are used rather than density variables. The design region is subdivided into a large number of separate variables whose influence on the structure is calculated and optimized over a series of iterations. The large number of shape variables allows the user to create any reinforcement pattern within the design domain instead of being restricted to a few.