SEP 2018


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SEPTEMBER 2018 46 CompositesWorld FEATURE / Safe Cycling THERMOPLASTIC SYSTEMS Features ■ Creels ■ Tow Spreading ■ Waterborne Resin Application ■ Oven for Pre-Melting Resin ■ Resin Consolidation Die Application ■ Profile Thickness Systems ■ Compaction Rolls ■ Winders ■ Controls & Automation C. A. Litzler Co., Inc. 4800 W. 160th Street Cleveland, OH 44135 USA 216-267-8020 FIG. 4 Bike design: No simple matter This technical demonstrator of HyperSizer Express frame geometry for an optimized hardtail mountain bike shows a layup of 0°/90°/±45° tape plies. The ply schedule is designed to meet typical requirements for performance bike frames, including ply-based strength criteria (Ref: Tsai-Hill, Tsai-Wu, Tsai-Hahn) as well as pedaling stiffness requirements (transverse bottom bracket deflection) for efficiency, and head tube stiffness requirements (transverse head tube deflection) for handling. Source | Collier/HyperSizer Finding defects Because part failure at the speeds and road conditions experi- enced in today's cycling domain can be catastrophic for both bike and rider, nondestructive testing (NDT) of individual components and even the final bicycle can help identify and reduce defects in the manufacturing process. However, HIA-Velo's Pickman warns that NDT isn't enough. "You can learn some things from NDT, but to really learn through development, we test to failure, then cut the parts up to inspect the molding quality." Bressan agrees. "Honestly, with the first prototype, we just destroy the part. We cut the part in sections and see what we can see inside, to be sure the technology is working properly." Even then, he adds, there are physical limitations. Even when the part is destroyed, one may not be able to verify everything. After an accident, Bressan recommends C-scan tomography

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