Study of the Computational Efficiency and Validity of the Surface Response to Excitation Method

Abstract

Performance of the Surface Response to Excitation (SuRE) method was evaluated by using a low cost DSP system and spectrum analyzer. SuRE method excites the surface of the structure with a piezoelectric element. The generated vibrations of a critical point on the surface are measured with (a) piezoelectric element(s) or other sensor(s). The magnitude of the transfer function between the excitation and the sensory signal is monitored. The accuracies of the Teager-Kaiser (TKA), Goertzel, RMS and average of the positive values algorithms were evaluated for magnitude estimation. The SuRE method was used successfully for detection of the compression by using the DSP system. In addition, an applied compressive force, a change of the diameter of a hole and a composite coating was detected by using a spectrum analyzer. The study indicated that the SuRE may be used as a low cost alternative to impedance method. The cost and inconvenience of using multiple piezoelectric elements are the disadvantageous of the method. The main advantages of the SuRE are requirement of much cheaper and simpler equipment. Test time may be drastically shortened in low noise environments, many different transducers may be used for sensing and some directionality may be gained by carefully selecting the location of the sensor(s).