Laboratory nondestructive evaluation technology for materials characterization

Thompson, R. B.

doi:10.1007/bf00732043

Cited by 8 publications

(5 citation statements)

References 20 publications

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“…The ultimate goal of the majority of the applications of inverse scattering is to obtain a quantitative image [1] of a corrupted (such as by a crack: [2][3][4][5]), diseased (such as affected by a tumor: [6][7][8][9][10][11]) or otherwise inhomogeneous ( [12][13][14][15][16]) body. To do this in an oft-employed manner (e.g.…”

Section: Introductionmentioning

confidence: 99%

Multiparameter identification of a lossy fluid-like object from its transient acoustic response

Scotti

Wirgin

2013

Inverse Problems in Science and Engineering

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International audienceA transient acoustic wave multiparameter inverse problem is studied. The aim is to simultaneously retrieve three constitutive parameters and one geometrical parameter of a lossy fluid-like cylinder by nonlinear full-wave inversion of synthetic data. Contrary to most publications treating this subject, it is assumed herein that the retrieval model is not identical to the data model, this being so because some of the parameters (priors) in the retrieval model are different (by the simple fact of being more or less unknown) from their true counterparts in the data model. This so-called model discordance, which is the usual situation in real-world inverse problems, is a source of errors for the retrieval of the other parameters. Moreover, it is a source of non-uniqueness and instability, a fact revealed by the employment of a properly-tuned Nelder-Mead downhill Simplex optimization algorithm, and which requires a second-order regularization for its resolution. Retrieval errors as a function of prior uncertainty are computed, and found to be large, for various model discordance scenarios involving one or two uncertain priors, for data with and without noise

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Section: Introductionmentioning

confidence: 99%

Multiparameter identification of a lossy fluid-like object from its transient acoustic response

Scotti

Wirgin

2013

Inverse Problems in Science and Engineering

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“…Non-destructive testing (NDT), Non-destructive evaluation [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] (NDE) and Non-destructive inspection (NDI) are the techniques that are based [33][34][35][36][37][38][39][40][41][42][43] on the application of determining the characteristics of materials or components and for assessing life of the component by evaluating the detected inhomogeneities and harmful defects present in the component without impairing its usefulness. During service, many factors [17] like unanticipated stresses (residual and system), operation outside designed limits (excessive temperature and load cycling), operation and environmental effects, degradation of material properties in service, etc., which are difficult to predict, affect the designed life of the component.…”

Section: Non-destructive Evaluationmentioning

confidence: 99%

Characterization of Intermetallic Precipitates in Ni-Base Alloys by Non-destructive Techniques

Acharya¹,

Ramesh²,

Murthy³

2015

Superalloys

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The present industrial scenario requires all engineering structure to be designed considering stability of several parameters at the operating conditions e.g. Temperature, pressure, resistance to mechanical and surface degradation . Choice of materials for any engineering component should be such that it operates safely for reliable function, without failure during in-service, giving optimum component life. Due to scarcity of various resources and cost of manufacturing, regular maintenance and evaluation of structural integrity at every stage of production is necessary. Nondestructive techniques NDT , along with modern computational facility help in nonintrusive investigation of the component at regular intervals of the operating stages for many critical applications. This will result in increment of designed component life and also help in maximizing utilization of natural resources.For long, Ultrasonic has been associated with defect detection, but with the recent advances in electronics in combination with computational capabilities Ultrasonic velocity measurements have also been attempted for characterization of solutionising and precipitation behavior in various alloy systems such as aluminium alloys, ferritic steel, maraging steel, nickel base alloys and titanium alloys. "s the speed of sound in a homogeneous medium is directly related to both elastic modulus and density, any changes in elastic property with varying degree of inhomogeneities will affect in pulse transit time through a sample of given thickness. Due to variation in elastic modulus of the matrix in the alloy resulting from the various precipitates it has been attributed towards the change in ultrasonic velocity of the alloy and thereby resulting in popularization of Ultrasonic testing for online monitoring of the component. The precipitation hardening has been believed to arise from the formation of very small solute clusters which uses significant scattering of the conduction electron cause © 2015 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.during the rearrangement, while the formation of the precipitates resulting in variation of electrical resistivity of the aged alloy.In the present chapter, a few non-destructive techniques used to characterize different microstructural features and the precipitation behavior, evolved through various heat treatments using Direct Current Potential Drop DCPD technique for measuring electrical resistivity and Ultrasonic Testing for measurements of ultrasonic parameters are presented. Further, validation of the observed results on microstructural features is also presented through hardness and microscopy studies.Thus, this study in effect can be used for non-destructive evaluation of the microstructures.

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“…Thus, any improvement to detect microstructural damage lower than this figure requires new, sensitive and reliable NDE tools. Recent literature reviews [18][19][20] provide many ideas in this respect. Yang and Fatemi [19] distinguish between two types of measurements: (i) surface and subsurface damage measurements and (ii) bulk damage measurements.…”

Section: Materials Characterization By Ndementioning

confidence: 99%

Fatigue Damage and Its Nondestructive Evaluation: An Overview

Buck

1998

Review of Progress in Quantitative Nondestructive Evaluation

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Laboratory nondestructive evaluation technology for materials characterization

Cited by 8 publications

References 20 publications

Multiparameter identification of a lossy fluid-like object from its transient acoustic response

Multiparameter identification of a lossy fluid-like object from its transient acoustic response

Characterization of Intermetallic Precipitates in Ni-Base Alloys by Non-destructive Techniques

Fatigue Damage and Its Nondestructive Evaluation: An Overview

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