Strain in BMX frame through different tests(Abstract)

摘要

The structural role of the bicycle frame is to transfer the mechanical energy produced by the cyclist at the rear wheel. In bicvcle cross (BMX) high ioads are applied on the frame, from the pilot, the field and the ground reaction. In BMX, the empirical design and the important power applied on the pedals can lead to the rupture of some tubes. The aim of this study is to equipped a BMX frame with stian gages and to measure the strain of the bicycle frame through tests representative of different actual race conditions 1) A bar system was designed to simulate the forces applied to the pedals by the pilot in static condition; 2) a pilot - applied a maximal isometric force on the pedal with help of handlebars (e.g., Competition start); and 3) a pilot performed one pedaling bout at a cadence of 200 rotations per minute and at power of 550 Watts. During the last two conditions, the tests were realized on an ergo-trainer with two 3D pedals and a SRM.