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Long Bai
University of Bristol
8Publications
3H-index
32Citations
Publications 8
Newest
#1Long Bai (UoB: University of Bristol)H-Index: 3
#2Alexander Velichko (UoB: University of Bristol)H-Index: 13
Last.Bruce W. Drinkwater (UoB: University of Bristol)H-Index: 35
view all 3 authors...
In the field of ultrasonic array imaging for non-destructive testing (NDT), material structural noise caused by grain scattering is one of the main sources of error when characterizing defects that are found in the polycrystalline materials. The existence of grains can also severely affect the detection performance of ultrasonic testing, making small defects indistinguishable from the grain indications due to ultrasonic attenuation and backscatter. This paper proposes a model in which the statis...
#1Chaoyong Peng (Southwest Jiaotong University)
#2Long Bai (UoB: University of Bristol)H-Index: 3
Last.Bruce W. DrinkwaterH-Index: 35
view all 4 authors...
Abstract Using ultrasonic arrays to detect and characterise surface breaking cracks is important in the non-destructive evaluation (NDE) field. It can provide early warning of failure and useful information for component integrity assessment. Typically, cracks are approximated by machined slots and used to examine and assess defect detection and characterisation methods. In this paper, real surface breaking cracks are fabricated in 3-point bending specimens following ASTM standard E1820 and used...
#1Bruce W. Drinkwater (UoB: University of Bristol)H-Index: 35
#2Long Bai (UoB: University of Bristol)H-Index: 3
Last.Alexander Velichko (UoB: University of Bristol)H-Index: 13
view all 3 authors...
#1Long Bai (UoB: University of Bristol)H-Index: 3
#2Alexander VelichkoH-Index: 13
Last.Bruce W. DrinkwaterH-Index: 35
view all 3 authors...
This paper studies ultrasonic defect characterisation with the aim of reducing the characterisation uncertainty. Ultrasonic array data contain a mixture of responses from all reflecting features, and the scattering matrix for each defect can be extracted in post-processing, which describes how ultrasonic waves at a given incident angle are scattered by a defect. In this paper, it is shown that defect characterisation performance can be improved by the inclusion of phase and frequency information...
#1Alexander VelichkoH-Index: 13
#2Long Bai (UoB: University of Bristol)H-Index: 3
Last.Bruce W. DrinkwaterH-Index: 35
view all 3 authors...
The aim of ultrasonic non-destructive evaluation includes the detection and characterization of defects, and an understanding of the nature of defects is essential for the assessment of structural integrity in safety critical systems. In general, the defect characterization challenge involves an estimation of defect parameters from measured data. In this paper, we explore the extent to which defects can be characterized by their ultrasonic scattering behaviour. Given a number of ultrasonic measu...
#1Long Bai (UoB: University of Bristol)H-Index: 3
#2Alexander Velichko (UoB: University of Bristol)H-Index: 13
Last.Bruce W. Drinkwater (UoB: University of Bristol)H-Index: 35
view all 3 authors...
In the field of nondestructive evaluation, accurate characterization of defects is required for the assessment of defect severity. Defect characterization is studied in this paper through the use of the ultrasonic scattering matrix, which can be extracted from the array measurements. Defects that have different shapes are classified into different defect classes, and this essentially allows us to distinguish between crack-like defects and volumetric voids. Principal component analysis (PCA) is u...
#1Long Bai (UoB: University of Bristol)H-Index: 3
#2Alexander Velichko (UoB: University of Bristol)H-Index: 13
Last.Bruce W. Drinkwater (UoB: University of Bristol)H-Index: 35
view all 3 authors...
Crack-like defects form an important type of target defect in nondestructive evaluation, and accurately characterizing them remains a challenge, particularly for small cracks and inclined cracks. In this paper, scattering matrices are used for defect characterization through use of the correlation coefficient and the structural similarity (SSIM) index as similarity metrics. A set of reference cracks that have different lengths and orientation angles are compared with the test defect and the best...
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