Lightweight design for an engine structural part by using topology optimization for additive manufacturing

Lightweight design is becoming increasingly more important for vehicle design in aerospace and automotive industry. Although very important advances achieved in product design for both industry, some innovative designs could not be implemented due to the production restrictions. By means of emerging technologies in additive manufacturing, the ways of product design, development and logistics are transforming. Current advances in AM materials and creative design methods enable AM integration for lots of industries. One of the major tools of the creative design is topology optimization which was used for years in product optimization. However, lots of design restrictions observed due to the manufacturing constraints such as mold direction, draft angle, equal wall thickness, etc. By means of AM, topology optimization results have the possibility to be directly integrated as much as possible. Design freedom is the most important advantage of the AM. It is obvious that both designers and manufacturers have this freedom. Designers can create the designs in a wide range of alternatives, suppliers can produce the complex features easier than the conventional production methods. Although design implementation is easier than the conventional methods, design verification is a must and have to be applied as part and system level. The verificaiton methods are nearly same compared to the conventional designs. As digital verification, modal analysis and structural stress analysis have to be aplied on the design. In literature review, mainly focused on topology optimization and integration with AM. First, an automotive driveline bracket topology optimization example shared according to the conventional production methods. Design and non-design space definition, modal assesment and weight reduction studies showed in the example.It has been very common application in automotive and aeorospace application up to now. Then, a re-design study of an AM aerospace hinge bracket shared to show the transformation of the design while changing production method. Very significant weight reduction obtained by means of material change and design update. Lastly, different AM design approaches showed while integrating TO results to the conventional design. Direct integration of TO or partly integration of TO and standart CAD remodelling of the part is possible. Most important advantage of the partly integration is to having updatable 3D model to enable model updates in any phase of the product lifecycle. Topology optimization theory and methods explained shortly in second section. Although size, shape and topology optimization is used as the structural optimization methods, only topology opimization used as the optimization method in this thesis. Density and homogination methods explained also. Additive manufacturing history, definition, technologies, materials and dimensional accuracies explained in third section. Clear understanding of AM capabilities and currrent apllication is very crucial for a successful design integration in all industries. For a successful lighweight design integration, AM manufacturing methods have to be known very well to prevent design phases. Effective software tool usage are also very important for the design transformation and virtual verification of the updated design. Catia V5 used for design space creation and meshing works completed in Hypermesh. Then, FE model creation, modal analysis and stress analysis performed in Abaqus. As a post process tool, Hyperview used to view the analysis results. After completion of the design space analysis, TO initiated in Tosca which is compatible with Abaqus models. According to the TO results, first 3D model phase created and modal analysis performed to check whether the target achived or not. Due to the lower values of first mode, further phases were required. Afterwards, second 3D model phase performed to get higher frequency results. Finally, modal and stress analysis of second phase performed in Abaqus and targets achieved for both of them. Final model has very complex features for conventional production methods, also manufacturability of the final part is nearly impossible by using conventional manufacturing methods. On the other hand, AM feasibilty seems very promising with the help of advanced capability of the AM technologies.