Abstract: Referring to state of distortion of bogie frame in the running line and the definition of the test method of bogie torsional stiffness according to the standard JIS E4207-2004 General rules for railway vehicle-bogie-bogie frame design, an improved torsional stiffness test method is proposed. The improved test method is more simple and practical, and errors can be effectively controlled within 7%. According to the different structural design forms, bogie frames are classified into box beam type and pipe beam type. By using the improved torsional stiffness test methods, these two types of bogie frames are tested, respectively. Meanwhile, the reasons for different torsional stiffness of the two types of bogie frames are analyzed from the theoretical perspective. Though simulation analysis on the two types of bogie frames with ANSYS software, conclusions are reached that the difference of the torsional stiffness of the bogie frames mainly depends on the cross-sectional area of the side beam under measurement and the structure types of the cross beam; torsional stiffness of frames in the structure of pipe beam is smaller than that in the structure of box beam; and the torsional mode frequency of box beam type is higher than that of pipe beam type, therefore, the dynamical stress amplitude of box beam type is smaller than that of pipe beam type in the area significantly influenced by the bogie torsional deformation, such as connection locations between cross and side beams.

Key words: box beam type frame, fatigue strength, frame, pipe beam type frame, torsional rigidity