Dynamic Properties of Hybrid Composite Hollow Cylinders: Application for Mountain Bicycle Handlebars

Supervisor: Prof. Larry Lessard

Dynamic properties of materials are of special interest to the sports industry, where strength and damping are required for optimal feel and performance. Hybrid composites made of synthetic carbon and natural flax fiber reinforcement were studied for dynamic performance optimization, for the purpose of a mountain bicycle handlebar. Hybrid laminate configurations were first optimized through modeling of handlebar behaviour to ensure the designs met required strength specifications. The effect of flax layer placement and multiple flax layers were experimentally determined through multiple dynamic testing methods in the free-free and clamped boundary conditions. The through-thickness strain energy density was modeled for all laminates to determine the relationship between the observed damping behaviour and the prominent damping mechanisms. Based on the observed dynamic behaviour and modeled strain energy density, an optimal layup was proposed for the handlebar. The design static strength requirements were verified through modeling, and a prototype handlebar was successfully manufactured. The study shows that the hybrid laminate design can be tailored to optimize the damping characteristics of a structure without compromising strength. 

Hybrid composite handlebar