Monitorization of crack propagation in welded aluminium assemblies

Abstract

Utilizing welded assemblies of aluminum profiles presents an effective means of reducing mass in rolling stock. However, these lightweight and optimally stiffened structures might be susceptible to unexpected failure modes that were not accounted for during the design phase. This could be due to insufficient information about in-service conditions or uncertainties in the material and manufacturing processes. This study aims to assess the feasibility of monitoring welded aluminum assemblies in real-time under both static and cyclic loading conditions to evaluate their structural health. Mechanical tests were conducted on welded aluminum profile assemblies while employing piezoelectric wafer active sensors (PWAS) for continuous monitoring. The PWAS facilitated ultrasonic active and passive inspections during testing. Passive sensing involved utilizing the acoustic emission technique to locate the source of acoustic signals associated with damaging mechanisms like crack nucleation and propagation. Upon identifying a detrimental event, on-demand active inspections using Ultrasonic Guided Waves were deployed to examine the structure and gather crucial information about its current condition based on analyzing temporal signal features. Although our mechanical tests were conducted in a laboratory environment, we recorded some temperature variations. Hence, we compensated for environmental influences through a data fusion model. Additionally, repetitivity analyses were conducted to confirm the reliability of the proposed inspection technique. Encouragingly, results demonstrated consistency and reliability in this proposed method.