Lyаsota I. Methodological foundations of acoustic emission diagnostics of aluminum alloy welds fracture

Elastic waves fields that are generated by fracture initiation of weld zones under action of quasi-static and cyclic loading are the investigations object. Acoustic emission diagnostics methodology of fracture of welded structure elements made of aluminum alloy are built using complex of investigations that includes the calculation methods of temperature fields and residual stresses estimation, metallography, fractography, speckle interferometry, approaches of linear fracture mechanics, analysis of wavelet transformations of acoustic emission signals etc. Quantitative factors were found to assess fracture initiation and fracture development of weld zones and base metal using parameters of acoustic emission elastic waves. It was revealed that early stages of damages accumulation for every weld zone caused acoustic emission signals generation of distinctive amplitude-frequency characteristic for both static and fatigue fracture. The dependences relating amplitude characteristics of registered acoustic emission signals to the area of created microcrack new surfaces were obtained. The diagnostics methodology of actual objects under test was proposed.