Measurement of fatigue cracks by nondestructive testing

Abstract EN

Detection of cracks in metallic specimens subjected to fatigue loading by nondestructive inspection techniques is demonstrated.

In the exper- imental phase of this study, standard rod specimens were fatigue loaded.

The tests were performed at different constant stress amplitudes at room tempera- ture.

To measure crack size, the specimens were removed from the testing machine after certain number of load cycles and were nondestructively inspected via ultrasonic, eddy current and X-ray techniques.

In this way a measure of the crack width and depth as function of the applied load level and number of cycles was obtained.

A brief review of the methods of nondestruc- tive inspection of fatigue cracks is also given.

Advantages and disadvantages of the different inspection techniques are discussed.

It is concluded that the ultrasonic inspection is the most reliable method.