Strength Design of Lightweight Composite Bicycle Frame

Strength design for a lightweight bicycle frame made of carbon/epoxy composite laminates was studied using Tsai-Wu's failure criterion. For the design of bicycle frames, reducing the weight of the frame is of great importance. Furthermore, the frame should satisfy the required strength under specific loading cases. In accordance with the European EN 14764 standard for bicycle frames, three loading cases-pedaling, vertical, and level loadings-were investigated in this study. Because of the anisotropic characteristics of composite materials, it is important to decide the appropriate stacking sequence and the number of layers to be used in the composite bicycle frame. From finite element analysis results, the most suitable stacking sequence of the fiber orientation and the number of layers were determined. The stacking sequences of [0](8n), [90](8n), [0/90](2ns), [+/- 45](2ns), [0/+/- 45/90](ns) (n = 1, 2, 3, 4) were used in the analysis. The results indicated that the [0/+/- 45/90](3s) lay-up model was suitable for a composite bicycle frame. Furthermore, the weakest point and layer were investigated.