FEM Analysis of Double Legs Bracket to Reduce the Local Stress Concentration for Automobile Applications

Generally, vehicle sensor on bracket is installed in engine room to receive sensing signals directly. The brackets in the engine room are exposed to extreme environmental conditions such as high temperature and irregular vibrations. For ease of production, traditional bracket structure has cantilever frame with one leg and two fixed points that is vulnerable to local stress concentration. High local stress in the bracket structure results in malfunctions and shorten life span. From these points, we suggest double legs and two fixed points bracket model with various hinge structures for local stress decreasing. To analysis the stress distribution and working conditions, vibration durability tests are performed for traditional and modified bracket models via finite element method. Impact hammer and grid tests are performed to validate the FEM analysis. Maximum stress conditions are evaluated with resonance frequency vibration analyses. As a result, the maximum stress on double legs bracket with increased thickness and radius of curvature model is reduced to 51.0% compared than traditional single leg bracket model.