Based on the tests about vibration fatigue crack growth of TC4 plate
the relationship between crack growth life and crack length was got. Using the ultra-depth microscope to observe and analyze the crack shape
the crack shape parameter was fitted. The fitted parameter was applied to calculate the stress intensity factor range and predict the crack growth life. Comparing the test results with prediction results
it showed that the crack shape parameter greatly influenced the predicting results. When the parameter was given a constant value
the error between the prediction and tested results was large. However
the fitted crack shape parameter can be used to predicted the crack growth life much more conveniently and accurately.