3-D Design for Additive Manufacturing Utilizing Topology Optimization

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Sabiston, Graeme
Topology Optimization , Additive Manufacturing , Aerospace Engineering , Computational Methods
As the frontier of modern-day engineering challenges pushes forward, the integration of multiple strategies to reduce manufacturing cost and increase component performance has engineers turning to tools such as topology optimization (TO) and additive manufacturing (AM). Recent focus on synthesizing AM and TO has led to efforts aimed at integrating these topics into the conventional design cycle. This manuscript combines two separate research efforts that address the current roadblocks preventing the proliferation of AM technology: The first topic of 3D Topology Optimization for Cost and Time Minimization in Additive Manufacturing expands upon existing mathematical constructs by providing an algorithm to minimize the cost and time associated with AM parts. The formulation has been constructed in such a manner to accommodate topology optimization problems with high element counts; this includes a filtering scheme requiring minimal computational storage and an iterative finite element solver. In order to determine the optimal contribution of AM factors to minimize build time, a rigorous trade-off analysis is conducted. It was found that build time could be decreased by over half for only small decreases in performance – on the order of 7-18% – when the method was applied to academic test problems. The second topic of Void Region Restriction for Additive Manufacturing via Diffusion Physics Approach addresses the issue of eliminating the emergence of void regions TO results in order to render the designs manufacturable by AM. By developing better, computationally efficient solutions to this problem, the integration of these two advanced technologies can be fully realized. A particle diffusion-void restriction (PDVR) method is presented in this work, capable of encouraging the optimization scheme to generate final designs that are fully accessible. Additionally, this method empowers the user to choose the type of post-processing method to clear support material (e.g. three-axis/five-axis milling operations, number and orientation of part set-ups) and therefore quantify the level of costs associated with the post-processing operation. Applied to test problems physically fabricated by AM, baseline designs that possessed inaccessible regions were made to be almost completely accessible by utilizing PDVR for increases in compliance on the order of 10%.
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