Strain analysis by means of digital shearography: Potential, limitations and demonstration

1998 ◽  
Vol 33 (2) ◽  
pp. 171-182 ◽  
Author(s):  
W Steinchen ◽  
L X Yang ◽  
G Kupfer ◽  
P Mäckel ◽  
F Vössing
Keyword(s):  
Strain Measurement ◽  
Speckle Pattern ◽  
Strain Analysis ◽  
Measuring Method ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Out Of Plane ◽  
Recent Developments ◽  
Plane Displacement ◽  
Non Destructive

Shearography, also called speckle pattern shearing interferometry, is a coherent optical method which measures displacement derivatives directly. It is suited well for localization of strain concentrations and has been used as an industrial tool for non-destructive testing (NDT) in the last few years. However, its application for strain measurement has not been widely adopted in industry, because, in general, shearography can measure only out-of-plane displacement derivatives ∂w/∂x and ∂w/∂y. This paper presents recent developments of shearography for strain measurement. With the support of digital image processing the automatic and quantitative evaluation of the shearogram becomes possible. Not only flexural strains [∂2w/∂x2, ∂2w/∂y2 and ∂2w/(∂y)] but also in-plane strains (∂u/∂x, ∂v/∂y, ∂u/∂y and ∂v/∂x) can be determined by the shearographic measuring method. The potentials and limitations for strain measurement are discussed. Some applications are shown.

Electronic Speckle Pattern Interferometry Applied to the Displacement Measurement of Sandwich Plates with Single ‘Fully Potted’ Insert

2004 ◽  
Vol 20 (4) ◽  
pp. 273-276 ◽  
Author(s):  
S. J. Huang ◽  
H. L. Lin
Keyword(s):  
Speckle Pattern ◽  
Fem Analysis ◽  
Electronic Speckle Pattern Interferometry ◽  
Sandwich Plates ◽  
Destructive Testing ◽  
Displacement Fields ◽  
Full Field ◽  
Out Of Plane ◽  
Plane Displacement ◽  
Non Destructive

AbstractThe construction and operation of electronic speckle pattern interferometer (ESPI) applied to single-inserted sandwich plates have been earliest presented in this paper. Proposed ESPI has advantages of full-field and non-destructive testing, which can measures microscopic out-of-plane displacement in the elastic region without wasting specimen. For validation purpose, the finite element method (FEM) analysis was conducted. By comparing the results of ESPI and FEM displacement fields around the inserts that a convincing agreement is revealed. The effect of potting material diameter on the displacement of single-inserted sandwich plates was obtained by the ESPI and FEM.

A Review of the Metal Magnetic Memory Technique

2016 ◽  
Author(s):  
Sheng Bao ◽  
Meili Fu ◽  
Shengnan Hu ◽  
Yibin Gu ◽  
Huangjie Lou
Keyword(s):  
Experimental Investigations ◽  
Magnetic Memory ◽  
Metal Magnetic Memory ◽  
Non Destructive Testing ◽  
Early Failure ◽  
Destructive Testing ◽  
Damage State ◽  
Recent Developments ◽  
As Stress ◽  
Non Destructive

Metal magnetic memory (MMM) is a newly developed non-destructive testing (NDT) technique. It has potentials to detect early failure, such as stress concentration, micro-crack and fatigue damage of ferromagnetic components. This paper outlines the recent developments of the mechanism studies on the MMM technique. Several advances in experimental investigations on the MMM technique are also summarized, e.g. the factors which can influence the detection signals, the criteria for judging the damage state and the magnetic parameters which can be used to assess the testing results. Finally, some future development trends about this technique are suggested.

The Non Destructive Testing Methods Applied to Detect Cracks in the Hot Section of a Turbojet

2011 ◽  
Vol 61 ◽  
pp. 79-83 ◽  
Author(s):  
Salim Bennoud ◽  
Zergoug Mourad
Keyword(s):  
Guided Waves ◽  
Effective Means ◽  
Industrial Applications ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
New Techniques ◽  
Scientific Approach ◽  
Recent Developments ◽  
Non Destructive ◽  
Standard Techniques

All aircraft whatever they are; are regularly audited. These controls are mainly visual and external; other controls such as "major inspection" or "general revisions” are more extensive and require the dismantling of certain parts of the aircraft. Some parts of the aircraft remain inaccessible and are therefore more difficult to inspect (compressor, combustion chamber, and turbine). The means of detection must ensure controls either during initial construction, or at the time of exploitation of all the parts. The Non destructive testing (NDT) gathers the most widespread methods for detecting defects of a part or review the integrity of a structure. The aim of this work is to present the different (NDT) techniques and to explore their limits, taking into account the difficulties presented at the level of the hot part of a turbojet, in order to propose one or more effective means, non subjective and less expensive for the detection and the control of cracks in the hot section of a turbojet. To achieve our goal, we followed the following steps: - Acquire technical, scientific and practical basis of magnetic fields, electrical and electromagnetic, related to industrial applications primarily to electromagnetic NDT techniques. - Apply a scientific approach integrating fundamental knowledge of synthetic and pragmatic manner so as to control the implementation of NDT techniques to establish a synthesis in order to comparing between the use of different methods. - To review recent developments concerning the standard techniques and their foreseeable development: eddy current, ultrasonic guided waves ..., and the possibility of the implication of new techniques.

scholarly journals Benefit of Neural Network for the Optimization of Defect Detection on Composite Material Using Ultrasonic Non Destructive Testing

2021 ◽  
Author(s):  
P. Trouvé-Peloux ◽  
B. Abeloos ◽  
A. Ben Fekih ◽  
C. Trottier ◽  
J.-M. Roche
Keyword(s):  
Defect Detection ◽  
Semantic Segmentation ◽  
Detection Methods ◽  
Learning Approaches ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Experimental Database ◽  
Out Of Plane ◽  
Non Destructive

Abstract This paper is dedicated to out-of-plane waviness defect detection within composite materials by ultrasonic testing. We present here an in-house experimental database of ultrasonic data built on composite pieces with/without elaborated defects. Using this dataset, we have developed several defect detection methods using the C-scan representation, where the defect is clearly observable. We compare here the defect detection performance of unsupervised, classical machine learning methods and deep learning approaches. In particular, we have investigated the use of semantic segmentation networks that provides a classification of the data at the “pixel level”, hence at each C-scan measure. This technique is used to classify if a defect is detected, and to produce a precise localization of the defect within the material. The results we obtained with the various detection methods are compared, and we discuss the drawbacks and advantages of each method.

Recent Developments on Welding, NDT and ECA of Clad and Lined Offshore Pipelines

2019 ◽  
Author(s):  
Petrônio Zumpano ◽  
Alexandre G. Garmbis ◽  
Diogo O. Moraes ◽  
Fausto Hirata ◽  
Bruno R. M. Cunha ◽  
...  
Keyword(s):  
Non Destructive Testing ◽  
Destructive Testing ◽  
Offshore Pipelines ◽  
Alloy 625 ◽  
Recent Developments ◽  
Bimetallic Materials ◽  
Corrosion Resistant Alloy ◽  
Purge Gas ◽  
Girth Welds ◽  
Non Destructive

Abstract Due to the level of contaminants of Brazilian pre-salt fields, alloy 625, e.g. UNS N06625, clad or lined steel linepipes have been chosen in order to resist such environmental conditions. Recent advances on welding, non-destructive testing (NDT) and Engineering Critical Assessment (ECA) approaches for bimetallic materials have significantly changed since discussed in OMAE-2012. Regarding welding of alloy 625 clad and lined pipes, maximum welding interpass temperature, back purge gas control, root discoloration, visual inspection, root profile for fatigue performance and other issues are discussed herein. The Fatigue Crack Growth Rate (FCGR) to be adopted for alloy 625 is still one of the issues, since curves for alloy 625 in specific environment are normally not available. New appendix C of DNVGL-RP-F108 gives orientations regarding how to conduct tests in sour environment. DNVGL JIP on clad and lined material has made an extensive approaching of the undermatching condition of alloy 625 weld metal under different design strain levels. Regarding NDT, developments and improvements in Automated Ultrasonic Testing (AUT) methods have been obtained for inspection of Corrosion Resistant Alloy (CRA) girth welds and weld overlay. Film and digital radiography are still used for the inspection of the pipe end of the mechanically lined pipe, but ultrasonic solutions are under development. Welding and NDT challenges of alloy 625 reported in 2012 have been overcame by state-of-art technologies used in offshore rigid risers construction and installation. Alternative CRA materials are under research and development, but alloy 625 still is the most reliable option.

scholarly journals Non-Destructive Testing of Materials in Civil Engineering

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3237 ◽  
Author(s):  
Krzysztof Schabowicz
Keyword(s):  
Building Materials ◽  
Civil Engineering ◽  
Current Trend ◽  
Building Structures ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Acoustic Methods ◽  
Recent Developments ◽  
Concrete Elements ◽  
Non Destructive

This issue was proposed and organized as a means to present recent developments in the field of non-destructive testing of materials in civil engineering. For this reason, the articles highlighted in this editorial relate to different aspects of non-destructive testing of different materials in civil engineering, from building materials to building structures. The current trend in the development of non-destructive testing of materials in civil engineering is mainly concerned with the detection of flaws and defects in concrete elements and structures, and acoustic methods predominate in this field. As in medicine, the trend is towards designing test equipment that allows one to obtain a picture of the inside of the tested element and materials. Interesting results with significance for building practices were obtained.

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