Semi-floating half-shaft rotation bending fatigue test device and method based on drive axle assembly

The invention relates to the technical field of drive axle test devices, and provides a semi-floating half-shaft rotation bending fatigue test device based on an drive axle assembly. The device comprises a test platform, two rim fixing devices mounted on the test platform, a drive motor and two loading mechanisms; each loading mechanism comprises a support frame mounted on the test platform and a stress application frame which is vertically mounted on the support frame in a sliding manner, and the lower end of the stress application frame is used for being propped against and matching a test sample bridge; and the device further comprises a lever mechanism which is arranged on the test platform and is used for applying downward acting force to the stress application frames. By arranging the lever mechanism and utilizing the lever principle, the gravity of a small mass block is amplified and is loaded to the test sample bridge through the stress application frames, meanwhile, the gravity of the mass block is n