Interpretation of Impact Echo time signals to avoid bias through geometry effects

The interpretation of Impact Echo signals has mostly been conducted in the frequency domain in the past. Due to its implementation as a scanning technique, so-called B-scans are generated for interpretation. However, as the method aims at the measurement of resonance frequencies, B-scans in the time domain are often neglected during interpretations. This study uses insights gained from numerical simulations to shed light on Impact Echo time signals in cases where geometry effects are present in the data. The focus is on noise reduction through new processing approaches, repeated measurements, and arrays. It was found that moving average filters are effective for removing reflection signals coming from the side walls. Furthermore, it is beneficial to focus on evaluating the start of Impact Echo time signals as the signal-to-noise ratio decreases over time.