Design and Analysis of Carbon/epoxy Composite Bicycle Handlebar

The fibre reinforced composite (FRC) came successfully in most domains of the global technology. Used in medical, military, performance sports, spatial domains or race cars building, these materials get to be used in our everyday life; even they have contributed significantly to the heightened performance of sports. Manufacturing of reinforced composite bicycle parts (frames, wheels, bar ends, handlebars and seat posts) has been significantly increased in the last decade. From the point of view of obtaining the tubular parts from FRP, the existent technologies mentioned in the literature is the filament winding or pultrusion (1-7). There are few scientific articles dealing with the analysis of composite tubes as part of a bicycle. Most of the studies (8, 9) are finite element (FE) analyses of the composite bicycle frames. In recent studies Liu and Wu (10) discussed about the fibre direction and stacking sequence design for a bicycle frame made of carbon/epoxy composite laminates. Under torsional, frontal, and vertical loadings, the normal and shear stresses with respect to the principal material coordinate system of each ply have been obtained from the finite element analyses. According to the maximum stress theory and the results of strength-to- stress ratios, optimal stacking sequence under three loading tests has been decided. The design of tubular parts must account of the material constants obtained on the same geometric shape of the structure. Usually the lay-ups design has influence upon the mechanical characteristics. The goals of this study were to design, manufacture, characterize and test a bent tubular carbon/epoxy fibre tube with variable section used as a bicycle handlebar. The tubular element made from carbon/epoxy was manufactured in the closed mould using an internal pressure. The two important tests for the handlebar, lateral bending test and torsional security test, provided by the DIN EN 14766:2006 (11) standard were simulated by FE and for the lateral bending an experimental validation have been done. Determination of the apparent material constants corresponding to a single-layer equivalent model was done theoretically based on classical laminated plate theory. To validate the theoretical results in terms of