Advanced Excitation Symmetry Analysis Method (ESAM) for improved automated ultrasonic testing within NDT4.0

Nonlinear acoustics and vibration has become increasingly important during the last forty years due to the increase of higher sensitivity of electronic instrumentation and its associate signal processing algorithms. The nonlinearity of materials results in nonlinear effects, which arise from defects in the materials present at all scales. The paper presents the Time Reversal based Nonlinear Elastic Wave Spectroscopy TR-NEWS device which is associated to the advanced Excitation Symmetry Analysis Method ESAM using chirp-coded excitations. The enhanced experimental device was tested with the V3 calibration block, improved and specially scaled in order to access to a wide range of multivalued parameters: mechanical properties, ultrasonic parameters (celerity and attenuation) and local geometric data. Linear and third order nonlinear signatures of material properties are measured and calibrated locally thanks to an optimized signal processing involving time reversal, correlation and pulse inversion algorithms. This experimental set-up fully controlled is considered as the first NDT4.0 based nonlinear NDT apparatus tagged “Industry 4.0”.