Experimental study of turbine disk residual stress measurement using Lcr wave

摘要

Turbine disk usually cracks near the arc junction between the rim and the plate (called the root of turbine disk). This paper presents the application of an ultrasonic method to measure stresses on the root of turbine disk. The ultrasonic residual stresses measurement is based on the acoustoelastic effect that refers to the change in velocity of the elastic wave when propagating in a stressed media. We employ critically refracted longitudinal waves(Lcr wave) and relate its time variation with applied stress. This paper studies the propagation law of Lcr wave in inclined surface of different angles and verifies that Lcr wave can propagate on rectangular components. The specific probe head is designed to detect residual stress on the root of the turbine disk. The experimental result shows that it is feasible to use Lcr wave to detect residual stress on the roots of the turbine disk.