3D ultrasonic inspection of anisotropic aerospace components

• Published in: Insight (Northampton) Vol. 52; no. 2; pp. 72 - 77
• Main Authors: Lane, C J L, Dunhill, T K, Drinkwater, B W, Wilcox, P D
• Format: Journal Article
• Language: English
• Published: Northampton British Institute of Non-Destructive Testing 01.02.2010
• Subjects: Acoustical measurements and instrumentation; Acoustics; Applied sciences; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Industrial metrology. Testing; Materials science; Materials testing; Mechanical engineering. Machine design; Physics; Acoustic measurement; Ultrasound imaging; In situ; Turbojet; Cracking; Anisotropic material; Modeling; Surface metrology; Ultrasonic imaging; Aerospace; Ultrasonic control; Internal structure; Turbine blade; Tridimensional image; Gas turbine; Plane antenna; Acoustic image; Non destructive test; Crack; Jet propulsion; Industrial technology
• ISSN: 1354-2575; 1754-4904
• DOI: 10.1784/insi.2010.52.2.72

Two-dimensional (2D) ultrasonic arrays for non-destructive evaluation will enable the detection and characterisation of sub-surface defects in three-dimensions (3D). This type of volumetric inspection is desirable when testing engineering components that have an inherent 3D internal structure or may contain defects orientated at a range of angles. One potential industrial application for this technology is the in-situ inspection of jet-engine turbine blades for root cracking. However, modern turbine blades are manufactured from single crystals of nickel-based superalloys for the excellent mechanical properties these materials exhibit at elevated temperatures. Single-crystal materials are elastically anisotropic, which causes ultrasonic waves to propagate with different velocities depending on the direction of the wave. If unaddressed, this significantly reduces the quality of the inspection and the 3D images that can be produced with an ultrasonic array. In this paper, a model of wave propagation in anisotropic media is used to correct an ultrasonic imaging algorithm to enable the reliable volumetric inspection of single-crystal aerospace components.