Acoustic emission as a tool for prediction of nugget diameter in resistance spot welding

Acoustic emission monitoring has been successfully employed in different application areas such as of fatigue loaded bridges and pressure testing vessels. However, this technology on resistance (spot) welding processes yielded limited results. Existing literature only mentions the detection certain defects expulsion cracked welds. Detecting nugget nucleation growth, to allow prediction diameter, never proven be feasible based acoustic signals. This work contains experiments varying well constant nominal parameter sets, where waveforms were collected during process. A methodology is described, revealing a correlation between frequencies present signal physical events occurring welding. Based these frequencies, model constructed for predicting diameter spot welds measurement data.