Layered Fiber Orientation Optimization for Long Fiber Reinforced Polymer Additive Manufacturing using Multi-Material Topology Optimization

Abstract

To iteratively produce lighter weight components, the use of topology optimization (TO) is instrumental in the design process. TO is used to determine the optimal placement of material within a design space and identify the critical load paths to designers. This allows for more organic lightweight designs to be developed. Further, multi-material topology optimization (MMTO) can be employed to optimize both the geometry and the material selection. This tool is powerful in the design process as it introduces new material options for the component that can be used to save even more weight. Although MMTO produces designs that are theoretically optimal for the problem statement given, they are often unmanufacturable. Traditionally, designers would interpret the optimization results manually to produce a manufacturable design. This deviates from the theoretically optimal solution created by the optimization and adds another step to the design process. To shorten the design process and maintain optimality, the design process should be considered within the optimization. Creating a set of constraints within the optimization that consider the limitations of the manufacturing process achieves optimal, yet manufacturable results. The long fiber reinforced polymer additive manufacturing (LFRPAM) process lends itself well to realizing MMTO results, as the process is capable of creating relatively high stiffness components with complex geometries. This research develops the material model and the set of constraints within conventional MMTO to create optimized results that are readily manufactured using the LFRPAM process. To demonstrate the MMTO for LFRPAM methodology it is applied to a number of case studies. The case studies compare MMTO for LFRPAM results to single material topology optimization (SMTO) results, and MMTO results without manufacturing constraints. The comparisons show the advantage of using MMTO for LFRPAM to create structurally optimal designs that are readily manufacturable with the LFRPAM process.