Characterization of Surface Crack Using Surface Waves

2012 ◽  
Vol 166-169 ◽  
pp. 1931-1934
Author(s):  
Shiuh Chuan Her ◽  
Sheng Tung Lin
Keyword(s):  
Surface Waves ◽  
Surface Crack ◽  
Crack Depth ◽  
Test Results ◽  
Ultrasonic Technology ◽  
Different Depths ◽  
Incident Waves ◽  
Non Destructive ◽  
Depth Detection

Surface cracks are the most common defects in structures. Ultrasonic has been widely used as a non-destructive evaluation technology in the case of crack characterization. In this investigation, surface waves are applied to a steel block with artificial slots to characterize the crack depth. A series of test specimen with different depths of surface crack ranging from 4mm to 10mm was fabricated. The depth of the surface crack was evaluated using the pitch-catch ultrasonic technology. In this work, 2.25 MHz, 5 MHz and 10 MHz of incident waves were employed to investigate the effect of frequency on the crack depth detection. Experimental test results show that the accuracy of crack depth detection is increasing with the increase of frequency.

Sizing Detection of a Surface-Breaking Crack by Ultrasonic Technique

2011 ◽  
Vol 52-54 ◽  
pp. 865-868 ◽  
Author(s):  
Shiuh Chuan Her ◽  
Sheng Tung Lin
Keyword(s):  
Test Specimen ◽  
Incident Angle ◽  
Ultrasonic Technique ◽  
Non Destructive Evaluation ◽  
Different Depths ◽  
Crack Sizing ◽  
Incident Waves ◽  
Surface Breaking Crack ◽  
Pulse Echo ◽  
Non Destructive

Ultrasonic is one of the most common uses of non-destructive evaluation technique. It could detect flaws inside the structure and on the surface such as voids, holes and cracks. In this investigation, a 304 steel block with a surface-breaking crack was fabricated. A series of test specimen with different depths of surface-breaking crack ranging from 2mm to 9mm was fabricated. The depth of the surface crack was evaluated by the pulse-echo ultrasonic technique. In this work, 2.25MHz, 5MHz and 10MHz of incident waves were employed to detect the depth of the surface-breaking crack. The effect of incident angle on the measuring accuracy was investigated. Experimental results showed that the accuracy of crack sizing detection by ultrasonic technique is not only dependent on the frequency of the incident wave but also dependent on the incident angle.

Assessment of a cracked reinforced concrete supporting structure for a converter in a steel melting shop through non-destructive testing and a statistical approach – a case study

2020 ◽  
Vol 62 (11) ◽  
pp. 633-641
Author(s):  
D Das ◽  
S R Debbarma ◽  
D Bouri ◽  
S Banerjee ◽  
S Chatterjee
Keyword(s):  
Reinforced Concrete ◽  
Crack Depth ◽  
Critical Conditions ◽  
Test Sequence ◽  
Steel Melting ◽  
Test Results ◽  
Scientific Review ◽  
Supporting Structure ◽  
Non Destructive

The subject of this paper is the occurrence of cracks and other types of damage, such as delamination of the reinforcement cover, carbonation, porosity, etc, which have occurred in a reinforced concrete supporting structure for a converter in a steel melting shop in India. The structure consists of two thick reinforced concrete walls on which the converter rests. Converters are used in a steel melting shop for blowing oxygen through hot metal and steel is produced through a reaction with carbon, silicon, phosphorus, sulphur, etc. A scientific review of the existing non-destructive test methods is carried out with reference to this case study and critical features of the testing process are described, which will help site engineers to correctly devise the test sequence and analysis procedure for assessment of the structures in specific critical conditions. Crack depth is estimated by analysing test results based on the ultrasonic pulse velocity. The paper explains how appropriate selection of the method and basic parameters is essential for estimating the most accurate crack depth. Lack of understanding of the existing condition of the material of the structure may lead to an incorrect interpretation of the test results. Further to this, a simple statistical procedure is described to identify significant cracks without detailed testing. The repair methodology and its specific features are also discussed in this paper. This case study on the assessment of the converter supporting structure will help engineers to provide solutions for similar types of damaged structure found in industry.

A Bayesian Approach for Effective Use of Multiple Measurements of Crack Depths

2020 ◽  
Author(s):  
Smitha D. Koduru ◽  
Maher Nessim ◽  
Steven Bott ◽  
Mohammad Al-Amin
Keyword(s):  
Depth Distribution ◽  
Crack Depth ◽  
Field Measurements ◽  
Crack Size ◽  
Multiple Measurements ◽  
Error Bias ◽  
Effective Use ◽  
Non Destructive ◽  
Size Estimates

Abstract A Bayesian methodology was applied to use data from multiple inline inspection (ILI) runs and field measurements with non-destructive examination (NDE) tools to increase confidence in crack size estimates. Multiple crack depth measurements were used in two different ways — namely, to improve the characterization of ILI sizing error bias and to update the maximum depth distribution of individual crack features. This methodology was applied to selected datasets from an industrywide database for crack ILI data collected over a series of Pipeline Research Council International (PRCI) projects. The results of the approach are presented for two datasets, showing reduced variance in sizing error bias and improved confidence in crack depth estimates. In addition to the PRCI datasets, an additional dataset was collected and used to investigate the effect of multiple ILI runs on estimates of rate of detection and depth distribution of undetected features. The results of this analysis are also summarized.

Non-destructive characterization of plasma-sprayed ZrO2 coatings by ultrasonic surface waves

1993 ◽  
Vol 224 (2) ◽  
pp. 177-183 ◽  
Author(s):  
Dieter Schneider ◽  
Thomas Schwarz ◽  
Hans-Peter Buchkremer ◽  
Detlev Stöver
Keyword(s):  
Surface Waves ◽  
Ultrasonic Surface Waves ◽  
Plasma Sprayed ◽  
Non Destructive ◽  
Non Destructive Characterization

scholarly journals Characterization of surface crack depth and repair evaluation using Rayleigh waves

2009 ◽  
Vol 31 (1) ◽  
pp. 77-83 ◽  
Author(s):  
D.G. Aggelis ◽  
T. Shiotani ◽  
D. Polyzos
Keyword(s):  
Surface Crack ◽  
Rayleigh Waves ◽  
Crack Depth

Assessment of influence of surface crack-like stress concentrators on main pipeline operability

2021 ◽  
pp. 8-15
Author(s):  
Дмитрий Александрович Неганов ◽  
Евгений Евгеньевич Зорин ◽  
Николай Евгеньевич Зорин
Keyword(s):  
Surface Crack ◽  
Surface Defect ◽  
Surface Defects ◽  
Test Results ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Stress Concentrators ◽  
Trunk Pipeline ◽  
Non Destructive ◽  
Twofold Excess

Устранение поверхностных трещиноподобных дефектов типа «риска» на участках подводных переходов магистральных трубопроводов возможно методом вышлифовки на глубину до 20 % толщины трубы. Ранее было подтверждено, что в подводных условиях все основные методы неразрушающего контроля позволяют стабильно выявлять имеющиеся в зоне вышлифовки произвольно ориентированные поверхностные дефекты протяженностью от 20 мм и глубиной от 1,5 мм. Однако при меньших геометрических параметрах дефектов имеется вероятность их неполного устранения либо необнаружения. Для оценки возможности эксплуатации трубопровода с поверхностным дефектом с учетом принятых режимов диагностики проведены циклические испытания по критериям механики разрушений полноразмерных образцов с нанесенными в зоне вышлифовки поверхностными трещиноподобными концентраторами напряжений указанных размеров. Все группы образцов показали более чем двукратное превышение длительности инкубационного периода развития трещины по сравнению с количеством циклов нагружения, которое может испытать трубопровод за средний межинспекционный период эксплуатации. По результатам испытаний подтверждена возможность проведения ремонта поверхностных трещиноподобных дефектов типа «риска» на подводных переходах магистральных трубопроводов с различным сроком эксплуатации методом вышлифовки без установки кессона на ремонтируемый участок. Elimination of surface crack-like defects of the “risk” type on underwater crossing sections of trunk pipelines is possible by grinding to a depth of up to 20 % of pipe thickness. Previously, it was confirmed that in underwater conditions, all main non-destructive testing methods make it possible to stably identify randomly oriented surface defects in the grinding zone with a length of 20 mm and a depth of 1.5 mm. However, with smaller geometric parameters of defects, there is a possibility of their incomplete elimination or non-detection. To assess the possibility of operating a pipeline with surface defect, taking into account the accepted diagnostic modes, cyclic tests were carried out according to the fracture mechanics criteria of full-size specimens with surface crack-like stress concentrators of the indicated sizes applied in the grinding zone. All groups of samples showed more than a twofold excess of the duration of crack development incubation period in comparison with the number of loading cycles that the pipeline can experience during the average inter-inspection period of operation. Based on the test results, the possibility of repairing surface crack-like defects of the “risk” type at trunk pipeline underwater crossings with different service life by grinding without installing a caisson on the repaired section was confirmed.

Non-Destructive Characterization of Welding Defects Using MMM and ACFM Methods

2014 ◽  
Vol 881-883 ◽  
pp. 1773-1777
Author(s):  
Ya Tian Gao ◽  
Li Hua Wang ◽  
Xiu Jie Miao ◽  
Jian Cheng Leng
Keyword(s):  
Detection Efficiency ◽  
Crack Depth ◽  
Magnetic Memory ◽  
Current Field ◽  
Tubular Specimen ◽  
Early Stress ◽  
Welding Defects ◽  
Non Destructive ◽  
Non Destructive Characterization

Nondestructive inspection and evaluation of welds is very important to ensure the safety of industrial products. In this study, the metal magnetic memory (MMM) and alternating current field measurement (ACFM) methods are utilized to characterize welding defects of a butt welded tubular specimen respectively. The results show that the MMM method has potentials in evaluating both early stress concentration and macro-defects but only qualitatively, while the ACFM method can provide crack depth sizing information quantitatively, suggesting that the two methods should be combined for nondestructive evaluation welding defects to improve the detection efficiency and accuracy.

Mechanical and Mineralogical Characterization of Mortar in Masonry Buildings Damaged by the 20-29th May Earthquake in Emilia

2014 ◽  
Vol 624 ◽  
pp. 379-386 ◽  
Author(s):  
Elisa Galli ◽  
Marco Savoia ◽  
Camilla Colla ◽  
Daniele Ferretti
Keyword(s):  
Chemical Properties ◽  
Test Results ◽  
Flexural Test ◽  
Mineralogical Characterization ◽  
Laboratory Test Results ◽  
Standard Specimens ◽  
Non Destructive ◽  
And Chemical Properties

The aim of the work is to characterize mechanical and chemical properties of the mortar, and thus the masonry, of historical buildings damaged by the Emilia May 20-29th 2012 earthquakes. The attention was focused on historical strategic buildings, located in Modena district. The experimental campaign here reported was carried out for each building through four steps: first, a mechanical characterization of masonry was performed in situ using non-destructive and semi-destructive methods (step 1); then, some materials were collected in order to obtain standard specimens of mortar joint and brick (step 2). In laboratory, those samples were properly prepared for testing (step 3) with compression and flexural test setups; finally, a limited number of those mortar samples were tested in order to obtain their chemical properties (step 4). The in-situ and laboratory test results were separately elaborated for mortar and brick, to characterize the single masonry components. The results were then used to estimate the characteristic masonry parameters. Criteria to obtain the masonry behavior were reviewed in order to give the average masonry parameters. The characteristic and average values of compression strength were compared with ranges provided in the codes for the same masonry typology.

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