Abstract
Ultrasonic methods have been extensively developed in nondestructive testing for various materials and components. However, accurately extracting quantitative information about defects still remains challenging, especially for complex structures. Although the immersion technique is commonly used for complex-shaped parts, the large mismatch of acoustic impedance between water and metal prevents effective ultrasonic transmission and leads to a low signal-to-noise ratio(SNR). In this paper, a quantitative imaging method is proposed for complex-shaped parts based on an ice-coupled full waveform inversion (FWI) method. Numerical experiments were carried out to quantitatively inspect the various defects in a turbine blade. Firstly, the k-space pseudospectral method was applied to simulate ice-coupled ultrasonic testing for the turbine blade. The recorded full wavefields were then applied for a frequency-domain FWI based on the Limited-memory Broyden–Fletcher–Goldfarb–Shanno (L-BFGS) method. With a carefully selected iterative number and frequency, a successive-frequency FWI can well detect half wavelength defects. Extended studies on an open notch with different orientations and multiple adjacent defects proved its capability to detect different types of defects. Finally, an uncertainty analysis was conducted with inaccurate initial velocity models with a relative error of ±2%, demonstrating its robustness even with a certain inaccuracy. This study demonstrates that the proposed method has a high potential to inspect complex-shaped structures with an excellent resolution.
Highlights
Rapid development in the fields of computer technology, manufacturing techniques and materials science makes the geometry of key components more complex
A single internal defect was embedded in a turbine blade to perform data processing and a parametric study of ultrasonic full waveform inversion (FWI) tomography
Conclusions this paper,ananice-coupled ice-coupled ultrasonic based on successive-frequency In In this paper, ultrasonictomography tomography based on successive-frequency full waveform inversion technology was proposed to quantitively inspect the defects in full waveform inversion technology was proposed to quantitively inspect the defects in complex-shaped parts
Summary
Rapid development in the fields of computer technology, manufacturing techniques and materials science makes the geometry of key components more complex. Technology has been widely applied in the aeroengine design due to the merits of a light weight, high aerodynamic efficiency, excellent fatigue resistance and high efficiency of fuel consumption [1]. Such monocoque components have been conveniently designed and fabricated by the emerging additive manufacturing (AM), known as 3D printing technology. AM has an excellent ability to manufacture complex-shaped parts with an optimal structure design, the quality of manufactured products may be influenced by buckling, residual stress and internal defects during the cooling process [2]. To guarantee the safety of these key components, special attention should be paid to the quantitative nondestructive testing (NDT) of complex-shaped parts
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
