Diagnosis of spot welded structures using elastic wave transmission and reflection characteristics

Abstract

An evaluation method for analyzing status of spot welded structures is proposed based on elastic wave transmission and reflection on beam structures. An elastic wave is generated and measured using piezoelectric excitation of a beam. For testing purposes, two beams are spot welded at evenly spaced locations, and several specimens were made using different currents and spot positions. For these beams the wave propagations are measured using identical piezoelectric actuation and sensing methods. Elastic wave propagations are analyzed using Timoshenko beam theory after taking the periodic constraints from the spot welding. The predicted propagation characteristics are compared to the measured ones for proposing diagnostic method. This provided non-destructing real-time monitoring of welded status.