Failure analysis of an automotive shock absorber cup during manufacturing process

LASEM, ENIS, Route Soukra, Km 3.5, B.P. 1173, 3038 Sfax, Université de Sfax, Tunisie

^a Corresponding author: nourahadjkacem@yahoo.fr

Received: 19 August 2015
Accepted: 6 January 2016

Abstract

A failure investigation was conducted on an automotive shock absorber cup during the manufacturing process. Due to the complexity of the parts, the manufacturing is carried out through multi deep drawing operations. The occurrence of cracks over the hole-flanged edge of the cups was the major problem in the forming process which causes failure. To determine the causes of failure, a detailed method including microscopic and macroscopic inspections were carried out in this study. The mechanical behavior of test specimens was investigated by means of tensile tests and the material was characterized in terms of Vickers micro-hardness. As a result, it was observed that the quality of the cut surface associated with the material work hardening after each sequence of sheet forming is the principal causes of failure. The damage is governed by the generation of micro defects during the punching process. This damage develops further during the hole-flanging step.