Topology Topology optimization and additive manufacturing: Comparison of conception methods using industrial codes

Additive manufacturing methods provide an increasingly popular industrial means of producing complex mechanical parts when classical methods are not suitable. The main advantage of these methods is the great freedom they give designers. At the same time, theoretical and numerical topology optimization tools can be used to simulate structures with complex shapes which exactly meet the mechanical constraints while requiring as little material as possible. Combining topology optimization and additive production procedures therefore seems to be a promising approach for obtaining optimized mechanical parts. Nonetheless structures obtained via topology optimization are composed of parts of composite densities which can not produced via additive manufacturing. Only numerical structures made of full or empty spaces only can be produced by additive methods. This can be obtained at the end of computational optimization through a penalization step which gives the composite densities from 0 to 1 the values 0 or 1. This means that the final part is different from the best solution predicted by topology optimization calculations. It therefore seemed to be worth checking the validity of an engineering approach in which additive methods are used to manufacture structures based on the use of industrial topology optimization codes. Here the authors propose to study, in the case of a simple mechanical problem, that of a metal cube subjected to a given pressure, three procedures, which differed in terms of the code and type of topology optimization calculations performed and the level of penalization applied. The three structures thus obtained were then produced using additive methods. Since all three structures proved to be mechanically resistant, the three procedures used can be said to be valid. However, one of them yielded better compromise between the mechanical strength and the amount of material saved. (C) 2017 The Society of Manufacturing Engineers. Published by Elsevier Ltd. All rights reserved.