Constraints of distance from boundary to skeleton: For the control of length scale in level set based structural topology optimization

A method is proposed for the control of minimum/maximum length scale in the level set based structural topology optimization. The minimum/maximum length scale of structure is characterized by using the concept of smallest/biggest maximal inscribable ball. In order to prevent trivial zero minimum length scale, the skeleton of structure is utilized and trimmed. The control of length scale is realized by constraining the distance from boundary to skeleton, and the distance is explicitly constructed by using the highly efficient fast marching method. Numerical examples in two dimensions are investigated.