Singer, Ferdinand; Institute of Sensor- and Actuator Technology Coburg; Germany
Singer, F.; Institute of Sensor- and Actuator Technology; Germany
Kufner, M.; Institute of Sensor- and Actuator Technology; Germany
Drese, K.; Institute of Sensor- and Actuator Technology; Germany
Session: Laser UT 2
Time: 11:10 - 11:30
In this paper, the propagation of Rayleigh waves on substrates with applied or residual stress is investigated. For this purpose the propagation of Rayleigh waves was measured with a Laser-Ultrasonic measurement system. It consists of a pulsed laser which excites broadband Rayleigh waves in a thermoelastic regime and a two-wave-mixing interferometer with a photorefractive GaAs crystal for robust detection of the surface waves. Both angular and frequency dispersion are considered theoretically and experimentally. It was found that there are clear indications of non-homogeneous stress states in the measurement results which qualitatively correspond with the theoretical models considered. However, some deviations between measurements and simulations still prevail, which may be attributed to effects not considered in the models. For grinded specimens, a clear dependence of a stress parameter on the grinding level was found which is also sensitive to annealing. This study is a work towards broader industrial application of Laser-Ultrasonic measurement systems.