'Faculty of Mechanical Engineering and Naval Architecture, Univ. of Zagreb'
Abstract
Evaluation of fatigue life of vehicles by using a real road test is very expensive; therefore, numerical methods such as Finite Element Method (FEM) are nowadays very popular for evaluating fatigue life. In this study, a method based on FEM is proposed for predicting fatigue strength of the chassis when designing and optimizing a semi-heavy truck. An experimental modal analysis has been applied for the validation of the finite element model which has been used in the proposed method. The natural frequencies and mode shapes of the chassis have been obtained from the finite element analysis and compared with the corresponding results of the experimental modal analysis. Also, a method for producing uneven roads in the time domain based on the International Reference Index (IRI) was introduced to simulate road roughness. In addition, different road types (with potholes and kerbs) and different load conditions (braking and cornering) have been considered throughout the simulation. In all of the mentioned conditions, stress time histories have been extracted and investigated. Finally, fatigue damage and strength of the chassis and welded connections have been estimated and described
