Experimental validation and prototyping of optimum designs obtained from topology optimization

This paper provides, through both numerical analyses and physical tests, a validation of the optimality of structural designs obtained from a topology optimization process. Issues related to the manufacturability of the topology-optimized design are first addressed in order to develop structural specimens suitable for experimental validation. Multidomain and multistep topology optimization techniques are introduced that, by embedding the designer’s intuition and experience into the design process, allow for the simplification of the design layout and thus for a better manufacturability of the design. A boundary identification method is also proposed that is applied to produce a smooth boundary for the design. An STL (STereo Lithography) file is then generated and used as input to a rapid prototyping machine, and physical specimens are fabricated for the experiments. Finally, the experimental measurements are compared with the theoretical and numerical predictions. Results agree extremely well for the example problems considered, and thus the optimum designs pass both virtual and physical tests. It is also shown that the optimum design obtained from topology optimization can be independent of the material used and the dimensions assumed for the structural design problem. This important feature extends the applicability of a single optimum design to a range of different designs of various sizes, and it simplifies the prototyping and experimental validation since small, inexpensive prototypes can be utilized. This could result in significant cost savings when carrying out proof-of-concept in the product development process. Z.-D. Ma (B) · N. Kikuchi · C. Pierre Department of Mechanical Engineering, University of Michigan, 2250 G. G. Brown Bldg., Ann Arbor, MI 48109-2125, USA E-mail: {mazd, kikuchi, pierre}@umich.edu H. Wang MKP Structural Design Associates, Inc., 3003 Washtenaw Ave., Ann Arbor, MI 48104-5107, USA E-mail: [email protected] B. Raju U.S. Army Tank-Automotive and Armaments Command