Research on Test Methods of Frame Torsional Rigidity

Frame torsional rigidity has great effect on the fatigue strength of the frame and the dynamic performance of vehicle. But the test for the frame torsional rigidity was very difficult. An improved torsional rigidity test method is proposed referring to analysis of distortion of frame in line running state and the definition of bogie torsional stiffness in the standard JIS E4207-2004. The improved test method is simple and practical, and error can be effectively controlled within 7%. According to the different structure designed type, the frame is classified as box beam type frame and pipe beam type frame. Take advantage of improved torsional rigidity test methods respectively test the two type frames, meanwhile analyses the reason in theory why frame torsional rigidity of two types are different. The results show that: the size of the torsional rigidity mainly depends on the cross-sectional area of the side beam and the structure of cross beam. The torsional rigidity of the pipe beam type frame is smaller than the torsional rigidity of the box beam type frame.