Projeto adaptativo da estrutura metálica de uma bicicleta

Abstract

This study presents an adaptive project of a 6061-t6 aluminum alloy metal structure for a mountain bike. The project was developed based on the original model, which experienced fracture failure. The objective of the adaptive project is to identify the root cause of the design failure and propose actions to eliminate or mitigate the problem, using the DFMEA methodology. The project scope follows the guidelines of SAE J1739 Standard, starting with the creation of a design tree and the development of DFMEA with analytical and numerical analysis actions. CAD tools were used for modeling, and FEA simulations were conducted under different scenarios proposed by the author to understand the structure's behavior during usage. Static simulations were performed to obtain the maximum Von Mises stress in order to validate the occurrence of ductile fracture. For fatigue fracture, the obtained value was compared with the fatigue limit stress calculated using the Marin equation. The results of the study indicated that the scenario where the rear wheel touches the ground first and the load is applied only on the front axle is the most critical for the failure region. However, the failure was not caused by a design error but by the manufacturing process, which was rectified through simulations applying a force 30 times greater than the combined weight of the cyclist and bike. Possible causes of the failure arising from the manufacturing process were identified, and DFMEA was employed to optimize the root cause identification process for bike frame failures.