STRESS ANALYSIS AT THE CRITICAL POINTS OF A STABILIZER BAR

The present work aims to analyze the fracture of a stabilizer bar of a passenger vehicle. The goal is to identify the structural stress on the bar and the region of fracture. The mechanical properties of the bar as the yield strength, the ultimate strength and elongation percentage was quantified using a universal testing machine. It was obtained the mechanical properties in tension and hardness of the bar material. The microstructure was characterized by optical microscopy. The observed microstructures were ferrite and pearlite. The steel used in the stabilizer bar has been classified by chemical analysis as SAE 1045. The analytical calculation of the stresses acting at critical points of the bar was performed to check the displacement range that the bar support without reaching the yield strength of the material. The strength criterion used for failure analysis was the maximum distortion energy (Von Mises), due to material work under cyclic torsion. By the Von Mises criterion, the stabilizer bar supports a stress of 503.4MPa for a displacement of 120mm. In the region of bar fracture, it was observed the propagation of radial cracks at the point of stress concentration towards the center of the bar. Analyzing structural stress, it is identified the need for improvement of the fatigue resistance for the material, since for displacement up to 120mm, the stresses calculated by the Von Mises failure criterion may cause the failure of the bar.