Self-calibrating ultrasonic technique for crack depth measurement

1992 ◽  
Vol 11 (2) ◽  
pp. 103-108 ◽  
Author(s):  
J. D. Achenbach ◽  
I. N. Komsky ◽  
Y. C. Lee ◽  
Y. C. Angel

With the increase in the fast track construction industries, the emerging techniques are used for improvement in the concrete strength and its properties. This paper focused on the test results for various mixes of concrete made by replacing OPC cement content with slag and fly ash in varying proportions the use of rapid hardening admixture along with the presence of crimped steel fibers. The flexural strength, crack depth measurement by using the ultrasonic pulse velocity and Elastic modulus of concrete were conducted with different proportions of fly ash (0-15%) and slag (0-25%) being replaced in cement and 0-50% of the fine aggregate is replaced with stone dust. The experimental test results show the volume reduction in flexural members, crack depth measurement by UPV and modulus of elasticity of concrete by scant modulus method was used for various mixes.


2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Ju-Yeong Jung ◽  
Hyuk-Jin Yoon ◽  
Hyun-Woo Cho

This paper seeks to propose an image-based noncontact testing method in crack depth measurement. To this end, it predicted the crack depth using the intensity values of cracks and verified its validity. To analyze the intensity values of cracks, eight stainless steel specimens with an increase in crack depths ranging from 0 to 17.5 mm at an average of 2.5 mm were fabricated, and a contrast index was attached to the center of the crack of the specimens painted with black matte spray for accurate analysis. Through various experiments, it was found that the intensity values of the cracks which decrease with the depth of the cracks were inductively formulated, and the average error was about 15% when the crack depth predicted by the empirical equation was compared with the actual crack depth. In addition, the validation of the intensity reduction equation obtained by the inductive method was verified, and it was confirmed that the crack depth can be predicted by the intensity value of the crack.


Author(s):  
Yannick Beauregard ◽  
Cody Edwards

This paper describes the analysis conducted on circumferential SCC found on a high vapour pressure ethane pipeline. The damaged section of pipe was located near a road crossing and was cut out before failure. A total of 146 cracks were identified with lengths ranging from a 1 mm to 50 mm. Three different techniques were evaluated for crack depth measurement: balanced field electromagnetic technique (BFET), sequential grinding, and microscopic cross-section examination. Crack depths of up to 2.6 mm (52% wall thickness) were identified. The failure pressure was determined by a burst test. The pipe began leaking at a pressure of 16 865 kPa, well in excess of the maximum operating pressure of 9930 kPa. The results of the burst test are compared to failure pressure calculations for an undamaged pipe and a pipe containing an axial crack with dimensions similar to the actual failed crack.


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