Mechanical, microstructural characterization and redesign of a BMX bicycle frame

Abstract

The high requirements of Bicycle Motocross (BMX) race conditions demands on the bicycle frame complex dynamic and static loads states by which it is expected that frames to experience high levels of stress and strain. To build efficient bike frames in terms of performance, weight and quality, it is necessary to analyse systematically its response against different loads. The aim of this work is to perform the design of a BMX frame for the national team of Colombia, including the microstructural and mechanical characterization of the initial bicycle frame as complement for the macrostructural characterization of the frame in static conditions. The components of the bike frame were exanimated using optical emission spectrometry, metallographic examinations, microhardness measurements and mechanical tests. It was found that significant differences of the grain sizes of the samples were reflected in the deformation values measured in the frame showing a high structural anisotropy. Despite this, the microhardness and mechanical resistance values the results show coherence between them. In Addition, safety coefficient of the four of the components of the bicycle frame was calculated finding that coefficient values was the calculated safe factor was 4.27. Copyright © 2018 VBRI Press