Nondestructive detection and analysis of stress states with polarized ultrasonic waves

THE APPLICATION of linear polarized shear waves is especially recommended in order to determine the (residual) stress states in structural elements. This technique results in equations for the stress evaluation which are independent of the ultrasonic path length measurement and in which only one of the three third-order elastic constants, namely n, must be known. Experimental results show that the third-order elastic constant n is, in contrast to l and m, constant over a considerable range of prestrain and changes only by about a few %, if the microstructure state is changed from a ferritic pearlitic over a bainitic to a martensitic-bainitic state. And finally, theoretical and experimental investigations of the dispersion of shear waves polarized II and I to the rolling direction indicate a very promising way in order to determine the (residual) stress states in cubic materials with rolling texture.