Mechanoluminescent Testing as an Efficient Inspection Technique for the Management of Infrastructures

2017 ◽  
Vol 12 (3) ◽  
pp. 506-514 ◽  
Author(s):  
Akihito Yoshida ◽  
◽  
Linsheng Liu ◽  
Dong Tu ◽  
Shigenobu Kainuma ◽  
...  
Keyword(s):  
Crack Detection ◽  
Fatigue Cracks ◽  
Steel Structures ◽  
Field Testing ◽  
Box Girders ◽  
Inspection Method ◽  
Steel Members ◽  
Precautionary Measures ◽  
Corrosion Protection Coating ◽  
Protection Coating

This paper reports on the mechanoluminescence inspection technology we have developed and its applications. The inspection technology is expected to identify deterioration and damage, such as fatigue cracks developed on steel members of steel structures, using particular mechanoluminescence (ML) phenomenon. In field testing at an urban highway bridge currently in service, fatigue cracks in steel box girders were successfully detected using the proposed technology. In addition, using a conventional crack detection method known as magnetic particle inspection (MT), similar results were obtained in terms of crack judgment, suggesting that the reliability of the ML method is equivalent to that of the MT method. An advantage of the ML inspection method is that it does not require removing corrosion protection coating, saving labor that is necessary in the MT method. The field testing also examined the possibility of evaluating precautionary measures (repair) as another application of the ML technique. As a result, the ML technique quantitatively evaluated that detected cracking had been properly repaired (removed). It is expected that the ML technique will contribute to effective maintenance and management of infrastructures from the perspective of preventive maintenance.

Low Frequency Phased Array Application for Crack Detection in Cast Austenitic Piping

2006 ◽  
Author(s):  
Michael T. Anderson ◽  
Stephen E. Cumblidge ◽  
Steven R. Doctor
Keyword(s):  
Stainless Steel ◽  
Crack Detection ◽  
Phased Array ◽  
Fatigue Cracks ◽  
Low Frequency ◽  
Pacific Northwest National Laboratory ◽  
The United States ◽  
Coarse Grained ◽  
Inspection Method ◽  
Centrifugally Cast

As part of a multi-year program funded by the United States Nuclear Regulatory Commission (US NRC) to address nondestructive examination (NDE) reliability of inservice inspection (ISI) programs, studies conducted at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington, have focused on assessing novel NDE approaches for the inspection of coarse-grained, cast austenitic stainless steel reactor components. The primary objective of this work is to provide information to the US NRC on the utility, effectiveness and reliability of ultrasonic testing (UT) as related to the ISI of primary piping components in US commercial nuclear power plants. This paper describes progress, recent developments and results from an assessment of a portion of the work relating to the ultrasonic low frequency phased array inspection technique. Westinghouse Owner’s Group (WOG) cast stainless steel pipe segments with thermal and mechanical fatigue cracks, PNNL samples containing thermal fatigue cracks and several blank vintage specimens having very coarse grains that are representative of early centrifugally cast piping installed in PWRs, were used for assessing the inspection method. The phased array approach was implemented using an R/D Tech Tomoscan III system operating at 1.0 MHz and 500 kHz, providing composite volumetric images of the samples. Several dual, transmit-receive, custom designed low-frequency arrays were employed in laboratory trials. Results from laboratory studies for assessing detection and localization are discussed.

Risk Based Inspection Planning for Fatigue Damage in Offshore Steel Structures

2015 ◽  
Author(s):  
Tom Lassen ◽  
Naman Recho
Keyword(s):  
Crack Propagation ◽  
Crack Detection ◽  
Fatigue Cracks ◽  
Steel Structures ◽  
Life Extension ◽  
Inspection Time ◽  
Reliable Estimate ◽  
Practical Case ◽  
Fatigue Reliability ◽  
Inspection Planning

High fatigue reliability is one of the most important design criteria for welded offshore steel structures. Due to repeated wave loading fatigue cracks may initiate and grow in welded joints that are important for the integrity of these structures. The present paper presents the methodology and the practical calculations for risk based inspection planning for fatigue cracks in welded details. Due to the uncertainty in the variables involved in the problem the planning has to be carried out by stochastic modeling and risk based assessments. Scatter in potential crack growth has to be analyzed by applied probabilistic facture mechanics and the uncertainty in the performance of the actual inspection technique has to be determined. With given risk acceptance criteria the practical outcome of the analyses is recommended inspection techniques and associated planned inspection time intervals. The classical theory is outlined and the latest recommendations from a Joint Industry Project recently completed by Det Norske Veritas in Norway are discussed. Discussion on how to model the fatigue process correctly is emphasized, particularly the role of time to crack initiation versus the subsequent crack propagation phase. Proper modeling of these two phases is crucial to get the potential crack path correct and thus obtain a reliable estimate of the probability of crack detection. For the crack propagation phase the selection of geometry functions is addressed. A practical case study for life extension of an offshore oil loading system is finally presented. A structural significant item in the system is the steel gooseneck connection for the sub-sea flexible loading hoses. The case is an interesting one in the way that two similar systems were analyzed independently, one analysis based on the tradition S-N approach and one where the decisions were reliability based by applying the Risk Based Inspection approach.

scholarly journals Pixel-Level Fatigue Crack Segmentation in Large-Scale Images of Steel Structures Using an Encoder–Decoder Network

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4135
Author(s):  
Chuanzhi Dong ◽  
Liangding Li ◽  
Jin Yan ◽  
Zhiming Zhang ◽  
Hong Pan ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Large Scale ◽  
Crack Detection ◽  
Fatigue Cracks ◽  
Steel Structures ◽  
Life Cycles ◽  
Detection Methods ◽  
Destructive Testing ◽  
Existing Structures ◽  
Fatigue Crack Detection

Fatigue cracks are critical types of damage in steel structures due to repeated loads and distortion effects. Fatigue crack growth may lead to further structural failure and even induce collapse. Efficient and timely fatigue crack detection and segmentation can support condition assessment, asset maintenance, and management of existing structures and prevent the early permit post and improve life cycles. In current research and engineering practices, visual inspection is the most widely implemented approach for fatigue crack inspection. However, the inspection accuracy of this method highly relies on the subjective judgment of the inspectors. Furthermore, it needs large amounts of cost, time, and labor force. Non-destructive testing methods can provide accurate detection results, but the cost is very high. To overcome the limitations of current fatigue crack detection methods, this study presents a pixel-level fatigue crack segmentation framework for large-scale images with complicated backgrounds taken from steel structures by using an encoder-decoder network, which is modified from the U-net structure. To effectively train and test the images with large resolutions such as 4928 × 3264 pixels or larger, the large images were cropped into small images for training and testing. The final segmentation results of the original images are obtained by assembling the segment results in the small images. Additionally, image post-processing including opening and closing operations were implemented to reduce the noises in the segmentation maps. The proposed method achieved an acceptable accuracy of automatic fatigue crack segmentation in terms of average intersection over union (mIOU). A comparative study with an FCN model that implements ResNet34 as backbone indicates that the proposed method using U-net could give better fatigue crack segmentation performance with fewer training epochs and simpler model structure. Furthermore, this study also provides helpful considerations and recommendations for researchers and practitioners in civil infrastructure engineering to apply image-based fatigue crack detection.

Fatigue crack detection method using analysis of vibration signal

2017 ◽  
Vol 1 (20) ◽  
pp. 63-74 ◽  
Author(s):  
Arkadiusz Rychlik ◽  
Krzysztof Ligier
Keyword(s):  
Crack Detection ◽  
Fatigue Cracks ◽  
Fatigue Cracking ◽  
Vibration Signal ◽  
Technical Condition ◽  
Visual Methods ◽  
Signal Characteristics ◽  
Fatigue Crack Detection ◽  
Sample Structure ◽  
Change Identification

This paper discusses the method used to identify the process involving fatigue cracking of samples on the basis of selected vibration signal characteristics. Acceleration of vibrations has been chosen as a diagnostic signal in the analysis of sample cross section. Signal characteristics in form of change in vibration amplitudes and corresponding changes in FFT spectrum have been indicated for the acceleration. The tests were performed on a designed setup, where destruction process was caused by the force of inertia of the sample. Based on the conducted tests, it was found that the demonstrated sample structure change identification method may be applied to identify the technical condition of the structure in the aspect of loss of its continuity and its properties (e.g.: mechanical and fatigue cracks). The vibration analysis results have been verified by penetration and visual methods, using a scanning electron microscope.

Static Electroplating of Iron Triad on Fastener Washers

2021 ◽  
Vol 879 ◽  
pp. 275-283
Author(s):  
Koay Mei Hyie ◽  
Salina Budin ◽  
Normariah Che Maideen ◽  
Yudi Rahmawan
Keyword(s):  
Carbon Steel ◽  
Low Cost ◽  
Sem Analysis ◽  
Nickel Iron ◽  
Cobalt Nickel ◽  
Protection Layer ◽  
And Performance ◽  
Resistant Layer ◽  
Corrosion Protection Coating ◽  
Protection Coating

Fasteners are commonly used in construction industry for parts joining purpose. There are many types of construction fasteners such as stud, bolt, anchor, nut, screw, and washer. The major problem of the fastener made by carbon steel is the poor resistance to corrosion. Electroplating is a simple yet low-cost tool to give a strong corrosion protection coating layer on the carbon steel. This study was performed to investigate the effect of current and deposition time on the iron triad (cobalt-nickel-iron) electroplating on the fastener washer. The experiment was conducted at 50 °C, pH 1-3 and at different electroplating time (30 minutes to 90 minutes) and current (0.2 A to 0.5 A). Burnt-out surface coating was observed on the fastener washer when the current was more than 0.4 A. A field test was carried out for 60 days to observe the corrosion behavior and performance of the products. Scanning electron microscope (SEM) analysis showed that a thin protection layer with 5.64 µm was formed at 60 minutes of electroplating time and 0.4 A of current. The surface roughness of the fastener washer was increased by increasing the electroplating time and current. The hardness was also improved with higher current and electroplating time if compared to the original fastener washer. The result of this study confirmed that a strong adhesive corrosion resistant layer to the fastener washer was using the current of 0.4 A (77 mA/cm2) and the electroplating time of 60 minutes.

scholarly journals Experimental Study on the Behavior of Tension Member Under Rupture

2021 ◽  
Keyword(s):  
Experimental Study ◽  
Tensile Force ◽  
Steel Structure ◽  
Steel Structures ◽  
Structural Members ◽  
Steel Members ◽  
Tension Member ◽  
Strong Relation ◽  
Almost All ◽  
Tension Members

Abstract. A steel structure is naturally lighter than a comparable concrete construction because of the higher strength and firmness of steel. Nowadays, the growth of steel structures in India is enormous. There are so many advantages in adopting the steel as structural members. Almost all high-rise buildings, warehouses & go-downs are steel structures and even some of the commercial buildings are made of steel. Tension members are the elements that are subjected to direct axial load which tends in the elongation of the structural members. Even today bolted connections play a major role in the connection of hot rolled structural steel members. In this experimental study the behavior of tension members (TM) such as plates, angles & channels have been studied under axial tensile force. There is strong relation between pitch and gauge (with in the specified limit as per IS 800:2007) in determining the rupture failure plane. In this study we intensively tested the behaviour of TM for different fasteners pattern by changing the pitch, gauge, end & edge distance and by adopting the different patterns or arrangements of bolted connection in it.

scholarly journals Mechanical Behavior of Damaged H-Section Steel Structure

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Xibing Hu ◽  
Rui Chen ◽  
Yuxuan Xiang ◽  
Yafang Chen ◽  
Qingshan Li
Keyword(s):  
Cross Sections ◽  
Elastic Moduli ◽  
Mechanical Test ◽  
Steel Structure ◽  
Steel Structures ◽  
Computational Accuracy ◽  
Cross Sectional ◽  
Steel Columns ◽  
Steel Members ◽  
The Cross

Steel structures are usually damaged by disasters. According to the influence law of the damage on the elastic modulus of steel obtained by the mechanical test of damaged steel, the average elastic moduli of H-section steel members were analyzed. The equations for calculating the average elastic moduli of damaged H-section steel members at different damage degrees were obtained. By using the analytical cross-sectional method, the cross-sectional M-Φ-P relationships and the dimensionless parameter equations of the H-sections in the full-sectional elastic distribution, single-sided plastic distribution, and double-sided plastic distribution were derived. On the basis of the cross-sectional M-Φ-P relationships and dimensionless parameters of actual steel members, the approximate calculation equations for the damaged cross sections were obtained. The Newmark method was used to analyze the deformation of damaged steel columns. Analytical results show good agreement with the test results. The equations and methods proposed in this study have high computational accuracy, and these can be applied to the cross-sectional M-Φ-P relationships and deformation calculation of damaged steel members.

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