Evaluating the Degree of Nonlinearity by Applying the Nonlinear SPC-I Technique in the FEM Simulation of Materials With Breathing Cracks

2021 ◽  
Author(s):  
SeHyuk Park ◽  
Hamad Alnuaimi ◽  
Umar Amjad ◽  
Tribikram Kundu
Keyword(s):  
Fatigue Cracks ◽  
Fem Simulation ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Micro Scale ◽  
Catastrophic Failures ◽  
Ultrasonic Techniques ◽  
Geometrical Effects ◽  
Non Destructive ◽  
Band Signal

Abstract Detecting internal defects such as fatigue cracks in their early stages is critically important to avoid catastrophic failures. However, detection of micro-scale defects poses a challenge to NDT/SHM (Non-Destructive Testing & Structural Health Monitoring) community. Conventional linear ultrasonic techniques that use absolute time of flight and attenuation to monitor damage progression encounter difficulty in detecting small defects. On the other hand, nonlinear ultrasonic techniques have been proven to be more reliable and sensitive to micro-scale defects. This study uses the nonlinear Sideband Peak Count Index (SPC-I) technique to evaluate the nonlinearity of the material. The problem is simulated using the finite element method (FEM). Fatigue cracks are simulated as breathing cracks. The problem is modeled as an infinite medium to minimize the geometrical effects such as reflections from the boundaries. A narrow band signal is excited and propagated through the material in a single sided excitation/detection setup. The degree of nonlinearity caused by breathing cracks is investigated for multiple configurations. First, the problem is modeled with no cracks to be taken as a reference condition. Then thick crack and thin crack (breathing crack) are modeled, analyzed, and compared. Finally, problems with different number of breathing cracks are simulated and analyzed. All simulated results are compared to investigate the dependence of the degree of nonlinearity on the density and orientation of the cracks.

scholarly journals Feasibility of Digital Image Correlation for Fatigue Cracks Detection under Dynamic Loading

Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6457
Author(s):  
Vladimir V. Bardakov ◽  
Artem Yu. Marchenkov ◽  
Anton Yu. Poroykov ◽  
Alexander S. Machikhin ◽  
Milana O. Sharikova ◽  
...  
Keyword(s):  
Digital Image Correlation ◽  
Dynamic Loading ◽  
Digital Image ◽  
Fatigue Cracks ◽  
High Sensitivity ◽  
Image Correlation ◽  
Stress Distributions ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Non Destructive

We address non-contact detection of defects in the railway rails under their dynamic loading and propose to combine digital image correlation (DIC) and finite element modeling (FEM). We show that accurate model of defect-free rail operating at the same loading conditions as the inspected one provides a reliable reference for experimental data. In this study, we tested the rail samples with artificial and fatigue defects under cyclic loading, calculated displacement and stress distributions at different locations of the cracks via DIC and validated the obtained results by FEM. The proposed DIC-FEM approach demonstrates high sensitivity to fatigue cracks and can be effectively used for remote control of rails as well as for non-destructive testing of various other objects operating under dynamic loads.

Productivity and Reliability Study of Non Destructive Testing Techniques for Inspection of Structural Welds in Construction Industry

NDT World ◽  
2016 ◽  
Vol 19 (3) ◽  
pp. 35-39
Author(s):  
Чан ◽  
Alan Chan ◽  
Бабу ◽  
Sajeesh Kumar Babu ◽  
Чан ◽  
...  
Keyword(s):  
Construction Industry ◽  
Ultrasonic Testing ◽  
Phased Array ◽  
Flaw Detection ◽  
Slag Inclusion ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Ultrasonic Techniques ◽  
Testing Techniques ◽  
Non Destructive

Introduction. The aim of this study is to evaluate the productivity and reliability of non-destructive testing techniques for the inspection of structural welds employed in the Hong Kong construction industry. Method. Manual ultrasonic pulse echo method and semi-automatic ultrasonic techniques using phased array (PAUT) as well as radiographic testing were employed. Five classes of defects were analyzed: lack of penetration, lack of fusion, crack, porosity and slag inclusion. The tests were carried out on the specimen made from structural plate, on which artefacts were inserted on the weld metal. The results were being studied to compare the defect detection reliability by both ultrasonic techniques. The flaw detection productivity using phased array is also compared with conventional ultrasonic testing at a determined rate. Results. The reliability of PAUT was 100% compared to 96.7% with manual ultrasonic testing, however with the inclusion of defect sizing and tolerance the reliability of manual UT is dropped to 57.4%, which implies there is a chance of 42.6% of improper sizing). PAUT exhibits the reliability of 87.5%. The research will be continued with the aim of determining the most appropriate and reliable NDT methods in each case.

scholarly journals Characterization and Comparison of Defects Detection Limits of Ultrasonic Non Destructive Techniques

2012 ◽  
Vol 498 ◽  
pp. 79-88 ◽  
Author(s):  
Elodie Péronnet ◽  
Florent Eyma ◽  
Hélène Welemane ◽  
Sébastien Mistou
Keyword(s):  
Defect Detection ◽  
Composite Structures ◽  
Aviation Industry ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Critical Defect ◽  
Critical Defect Size ◽  
Ultrasonic Techniques ◽  
Liquid Resin Infusion ◽  
Non Destructive

This work deals with the Liquid Resin Infusion (LRI) process developed within the research program “FUSelage COMPosite” of DAHER SOCATA. This manufacturing process enables the realization of complex composite structures or fuselage elements in a single phase (mono-material), which considerably reduce connections and relative difficulties. The concern here is the investigation of non destructive testing (NDT) methods that can be applied to LRI-structures in order to define their capacities for defect detection, and especially their associated critical defect size. In aviation industry, the AITM standards require the ultrasonic testing as NDT for composite materials. Therefore the aim of this work is to characterize and compare three different and complementary ultrasonic techniques on composite specimens. Such analysis allows to define the NDT application field of each method in term of defect detection.

The structural integrity of flash-butt welded premium rail steel – Evaluation of strength, microstructure and defects

2020 ◽  
pp. 095440972097313
Author(s):  
Anthony Micheletto ◽  
John Cookson ◽  
Yong Pang ◽  
Bernard Chen ◽  
Peter Mutton
Keyword(s):  
Structural Integrity ◽  
Rail Steel ◽  
Experimental Testing ◽  
Non Destructive Testing ◽  
Testing Methods ◽  
Destructive Testing ◽  
Integrity Assessment ◽  
Catastrophic Failures ◽  
Non Destructive ◽  
Microstructural Examination

Experimental testing of flash-butt welded premium rail steel samples was undertaken to quantify the variation in strength through the cross-section of the weld, with results showing a general correlation between the width of the heat-affected-zone and the ultimate tensile strength. Microstructural examination and fractography revealed the presence of defects in some samples. Large defects can be identified by non-destructive testing methods as part of routine structural integrity assessment; however, small defects may escape detection but could propagate under cyclic loading in service leading to catastrophic failures. This work demonstrates the requirement for stringent control of heat input to prevent the development of defects in premium rail steels with high alloying content.

scholarly journals Flaw detection of ship equipment parts

2021 ◽  
Vol 2131 (5) ◽  
pp. 052059
Author(s):  
A Kuznetsov ◽  
S Ivanchik
Keyword(s):  
Fatigue Cracks ◽  
Flaw Detection ◽  
Current Control ◽  
Operating Conditions ◽  
Magnetic Memory ◽  
Non Destructive Testing ◽  
Testing Methods ◽  
Destructive Testing ◽  
Advantages And Disadvantages ◽  
Non Destructive

Abstract The need for non-destructive testing is regulated by the rules of the Russian River Register, which can determine the choice of the method of non-destructive testing and the procedure for its implementation. Non-destructive testing methods used in naval mechanical engineering are: visual and measuring control, ultrasonic control, radiographic control, capillary control, magnetic control, eddy current control. Each of the methods, due to the difference in the implemented physical principles, has its own advantages and disadvantages, which impose restrictions on the flaw detection of parts. The analysis of the sculpted defects of ship equipment and machines, depending on the manufacturing method and operating conditions, was carried out. The limitations on the use of non-destructive testing methods are shown. Examples of non-flaw detective parts are given, the control of which is difficult, as well as flaw detective parts that can be controlled with a guaranteed condition for detecting defects. The advantage of the method of magnetic memory of metal is indicated, relative to other methods of non-destructive testing. Using the example of a piston pin of a marine diesel engine NVD 36, a comparative analysis of the applicability of ultrasonic testing methods, the magnetic memory method and the penetrating solutions method for detecting fatigue cracks was performed. The results of the control show that the applied methods confidently identify fatigue cracks in the controlled parts, machines and mechanisms of ship equipment.

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