Dynamic Correlation and Optimization of an SUV Rear Bumper Structure

摘要

Structural durability of different components and systems for a Utility Vehicle is critical to design, due to severe customer usage in rural zones and off road driving conditions. Physical validation of new component designs is time consuming, costly and iterative. Also, this process does not ensure an optimized structure. Through virtual validation it is possible in the initial phase of design to validate the structure and optimize the design. The core of a virtual validation process is to obtain accurate correlation which can replace developmental laboratory testing. Hence, only a confirmatory test can be carried out. This enables design optimization based on simulations. This paper presents the systematic approach used for optimization of SUV rear bumper and bumper mounting structure. Dynamic correlation is obtained for bumper structure subjected to the vibration levels as mapped from the proving ground test. The objective of new bumper development is for value engineering. Existing steel bumper of the vehicle is replaced by a plastic bumper. For mounting the bumper suitable mounting scheme is designed. The mounting structure is optimized for mass and to meet required strength. Several design iterations are carried out by Finite Element Analysis (FEA). The loads and boundary conditions are formulated such that it simulates the laboratory test. Confirmatory physical test is performed and first time right solution is achieved. To ensure robustness of FEA, the simulation results are correlated with laboratory test results. A correlation of 95% is achieved for natural frequency and strains with the measurements.