  The traditional element-based topology optimization based on material
penalization typically aims at a 0/1 design. Our numerical experiments reveal
that the compliance of a smooth design is overestimated when material
properties of boundary intermediate elements under the fixed-mesh finite
element analysis are interpolated with a material penalization model. This
paper proposes a floating projection topology optimization (FPTO) method for
seeking a smooth design using the ersatz material model or a 0/1 design using a
material penalization model. The proposed floating projection constraint
combining with the upper and lower bounds heuristically simulates 0/1
constraints of design variables in the original discrete optimization problem.
Numerical examples demonstrate the capability of the proposed element-based
topology optimization approach in obtaining 0/1 or smooth designs for 2D and 3D
compliance minimization problems. The proposed topology optimization approach
can be easily implemented under the framework of the fixed-mesh finite element
analysis and provides an alternative way to form explicit topologies of
structures, especially when the ersatz material model is adopted.

Computational Engineering, Finance, and Science;Numerical Analysis;Numerical Analysis