Replacing Structural Metal Joints in Next Gen Vehicles Using Aligned, Continuous Composites with Jim Nelson
Although advanced composite material outperforms metal on material data sheets, actual composite structures often fail to provide a significant improvement. In part, this is due to the application of design approaches that were originally meant for metallic constructions. As a result, advanced composite structures end up having a redundant layup, with a quasi-isotropic stacking sequence that eliminates anisotropy, instead of leveraging it, so called black aluminum. Todayâ€™s approach to take bet- ter advantage of continuous carbon fiberâ€™s mechanical properties, fibers are aligned based on the anticipated loading conditions. This can be achieved using hand layup or automated tape layup (ATL) / automated fiber placement (AFP) techniques. Though this provides a significant improvement over the â€œblack aluminumâ€� approach, it still falls short of realizing the full potential of continuous fiber anisotropy. Since carbon fibers perform best in tension, the part itself should be redesigned to take advantage of this effect. Though this exercise may seem intuitive for simple parts, in the aerospace industry these coupled design activities easily become non- intuitive due to the complex loading conditions the aircraft structures are subjected to. Arris Composites has developed a new process, additive molding, capable of manufacturing complex geometries, using continuous fiber. This paper presents optimizing topology and fiber orientation for an aerospace bracket, having complex 3D load cases. These optimized structures are shown to outperform current composite structures as well as structures machined and 3D printed from metal, making them ideal for next generation aerospace brackets and joining structures.