Stress measurement

What is NDT? 

Possible non-destructive methods are: X-ray diffraction; Barkhausen noise measurement; SPATE (Stress Pattern Analysis Thermal Emission); Neutron diffraction and scattering; Strain gauging; Electronic Speckle Pattern Shearing Interferometry (ESPSI); Alternating Current Stress Measurement.

There are also a number of methods of measuring the local stress in a specimen which, because they require some preparation of the surface or cutting out a sample piece for test, are not strictly non-destructive.