Estimation of Truck Frame Fatigue Life under Service Loading

The article presents the methods for experimental and theoretical research of vibration loads and dynamic stresses of automobile frame. The comparative analysis of the finite element stress and acceleration is performed with SolidWorks and Ansys software with the use of resistive strain gages and g-meters data obtained during automobile road tests. Frame fatigue life calculation of using multibody dynamics model in FRUND software is given. Load-carrying structures of automobiles undergo external loads which are time- and frequency-variable, depending on velocity, current weight, road profile and other factors. Such loading mode provokes the occurrence of fatigue cracks, and their promotion can entail fracture. Thus, frames and load-carrying structures are subjects of cyclic loading tests purposed to estimate stress level and reliability of the structures and detect possible failures. The motion was considered for following road types: concrete road, smooth cobblestone road and special cobblestone profile. Road types and automobile velocities are corresponding to input data for dynamic simulation in FRUND multibody dynamics system.