The setup and application of the multi-scale in-situ test system for fatigue damage analysis

This essays aims at introducing the setup for the multi-scale in-situ test system which is applied for the fatigue crack initiation test. The setup of the experiment system is first introduced, including the image capturing system, optical path system, image acquisition and storage system and the three-axis mobile platform. Then the preparation of micro speckle and the corresponding technique for spatial adjustment are improved to realize the DIC measurement in micro scale. Finally three experiments from macro-meso scale to macro scale: fatigue initiation test, the observation of micro crack and the fatigue crack growth rate in macro scale were conducted to verify the application of the system. The test result can indicate the location of crack initiation, the crack growth rate and the evolution of displacement/strain field, etc.