Fracture Characteristic of Automobile Structure Strengthening under Low Amplitude Load

The fatigue strength and life of automobile structures can be obviously increased by strengthening under low amplitude load.The mechanism of strengthening under low amplitude load was studied through the observation of fracture cross section of auto parts by means of SEM.Under proper strengtheneing loading,the microstructure became dense and homogeneous.Moreover,the number and diameter of voids and the number of secondary cracks decreased obviously.The fatigue crack initiation and propagating rate were reduced by strengthening under low amplitude loading.