[1B3] Robotic residual stress measurement using the phased array ultrasonic method
Y Javadi, M Vasilev, R Vithanage, A Hutchison, R Zimermann, D Lines, E Mohseni, C MacLeod,
G Pierce, J Mehnen and A Gachagan
University of Strathclyde, UK
Residual stress (RS) in engineering components can lead to unexpected and dangerous structural failures and thus represents a significant challenge to quality assurance in both welding and metal additive manufacturing (AM) processes. RS measurement using a phased array ultrasonic testing (PAUT) system, rather than the single-element ultrasonic method, is a new non-destructive evaluation (NDE) method developed by the Centre for Ultrasonic Engineering (CUE) to improve the measurement accuracy and allow robotic measurement.
Traditionally, the majority of RS measurement methods are carried out manually with some basic automation, where the whole process still requires supervision by a highly skilled operator. This paper aims to study the feasibility of the development of an innovative robotic system for RS measurement using the PAUT method. Using six-axis KUKA robots in the Sensor Enabled Automation, Robotics & Control Hub (SEARCH), robot programming and path planning are developed for RS measurement in components with complex geometries, such as wire arc additively manufactured (WAAM) samples, and with the complications of the unknown position of the heat-affected zone (HAZ) and weld, which requires more accurate positioning compared with the base metal. The feasibility of integrating this new system with the in-process high-temperature inspection system is also discussed and a new method for the measurement of the acoustoelastic coefficient is studied. The robotic RS measurement is shown to increase the measurement repeatability and PAUT sensor positioning accuracy as well as allowing the in-process RS measurement in the WAAM and welding components.
Keywords: residual stress (RS), non-destructive evaluation (NDE), phased array ultrasonic testing (PAUT), robotic NDE, wire arc additive manufacture (WAAM), heat-affected zone (HAZ).
Traditionally, the majority of RS measurement methods are carried out manually with some basic automation, where the whole process still requires supervision by a highly skilled operator. This paper aims to study the feasibility of the development of an innovative robotic system for RS measurement using the PAUT method. Using six-axis KUKA robots in the Sensor Enabled Automation, Robotics & Control Hub (SEARCH), robot programming and path planning are developed for RS measurement in components with complex geometries, such as wire arc additively manufactured (WAAM) samples, and with the complications of the unknown position of the heat-affected zone (HAZ) and weld, which requires more accurate positioning compared with the base metal. The feasibility of integrating this new system with the in-process high-temperature inspection system is also discussed and a new method for the measurement of the acoustoelastic coefficient is studied. The robotic RS measurement is shown to increase the measurement repeatability and PAUT sensor positioning accuracy as well as allowing the in-process RS measurement in the WAAM and welding components.
Keywords: residual stress (RS), non-destructive evaluation (NDE), phased array ultrasonic testing (PAUT), robotic NDE, wire arc additive manufacture (WAAM), heat-affected zone (HAZ).
