What types of signals are often used to as the actuation signals?
In principle, any signal waveform can be used as an actuation signal to be applied to the actuator. However, Lamb wave has the distinct property that different modes have different propagation velocities at different frequencies. This results in the phenomenon that the signal waveform received by a sensor is very different from the actuation signal. The broader the bandwidth of the actuation signal, the greater the dispersion. This requires that the actuation signal cannot be too narrow while this is highly desirable for detecting small damages. To balance this tradeoff, a Gaussian modulated burst with only several periods is often used. In Acellent’s products, we provide several choices for this purpose. In the meantime, we also provide a convenient tool for the user to design their own actuation signals.
