Corner Elimination in Discrete Topology Optimization of Compliant Mechanisms

State of material can be either void or solid in the optimization of discrete topologies. In the present discrete topology optimization, one main issue is the unsmooth boundaries. These are created due to subdivision techniques and exist as sharp corners in the topology solution. Even though outer corner cutting and inner corner filling method can reduce the corners, it cannot completely eliminate them. Corners that are at 90° are reduced to 135° using the corner handling strategy. The corners in existing topology solutions are because of the present subdivision model. A creative subdivision model is introduced, instead of regular triangular subdivision, to eliminate the corners in the optimization of discrete topologies in compliant mechanisms. A new method is introduced wherein the total design domain is divided into quadrilateral design cells. Each of these is again subdivided into special triangular analysis cells with curved hypotenuse. FEA is performed with these special triangular cells. With this special subdivision model, topology solution has smooth boundaries. Binary bit arrays are used to eliminate the problems of geometric bias against the vertical design cells, instead of binary bit string, in the genetic algorithm in finding out the optimal topology. Using this new subdivision technique, two discrete topology optimization examples on compliant mechanisms are solved. The results thus obtained are shown to be structurally good