Investigating hinge crack problem of a vehicle hood by integration of CAE and RLD analysis

In this paper, a good example on integration of CAE (Computer Aided Engineering) and RLD (Road Load Data) analysis is introduced. It works well in the process of investigating the hinge crack problem of a vehicle hood and leads to schemes which are suitable to the root cause found. As the byproducts, a design target is confirmed and a procedure of problem investigating is proposed, as shown in Flowchart 1. Flowchart 1Problem Investigating Procedure In order to ascertain the reason of the crack, multiple methods have been used, such as material verification, manufacturing examination, typical load case evaluation by CAE, and RLD analysis etc. Eventually, the reason is proved to be structural resonance by the common thread of both CAE and RLD. During the progress of problem solving, four main steps are involved and mentioned in the following sections. Firstly, right after the crack occurs, three kinds of CAE results including static stress analysis, hood slamming analysis, and constrained mode analysis, are reviewed. Then the only suspicious factor is noticed. Secondly, RLD acquisition is executed according to CAE suggestion, and the load spectrum gives the definite conclusion of resonance, as well as its vibrating frequency in accordance with CAE. Thirdly, it comes to another strong point of CAE to guide and to compare the design improvements. Lastly, the best optimized design scheme is verified by RLD analysis and general proving ground test in sequence. Copyright © 2013 SAE International.