TEJ KUMAR

Size optimization is performed for designs that use structural elements for analysis. The structural elements include truss, beams, frames, plates, shells, etc. In size optimization, the feature size of these elements which is usually the thickness or cross-sectional area is the design variable. An example of truss size optimization is demonstrated above where a uniform heat load is applied to all the topmost nodes and a temperature of 50-degree Celsius is applied to the bottommost nodes. The total truss volume is kept constant and the thermal compliance (analogous to structural compliance) is minimized. Notice the initial truss structure (and its non-uniformity) called ground structure and the final structure where the thickness of the truss members near the bottom has increased significantly.

 

A size optimization is relatively simple as compared to topology optimization and is preferred wherever possible to save computational cost and avoid any numerical issues involved in topology optimization. Topology optimization, on the other hand, can sometimes be used to get the region to generate the ground structure for size optimization.