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Full-Text Articles in Engineering Science and Materials

Hidrometalurjide Yeni, Fathi Habashi Jan 1979

Hidrometalurjide Yeni, Fathi Habashi

Fathi Habashi

Turkish translation of F. Habashi, “Recent Advances in Hydrometallurgy,” Proceedings International Mineral Processing Congress, Warsaw, 1979, edited by J. Laskowski, published by Elsevier, pp. 902–935


State Of The Art In Single Frequency Eddy Current Testing, K J. Law Jan 1979

State Of The Art In Single Frequency Eddy Current Testing, K J. Law

Review of Progress in Quantitative Nondestructive Evaluation

NDE in the mass production automotive industry uses single frequency eddy current test systems for component parts integrity testing. Typical measures accomplished are: surface hardness (Rc), depth of hardened layer (case depth), core hardness, and soft spots on the surface caused by incorrect quench. Additionally, gross crack and seam defects are detected in production processes by this type equipment, on the order of .005" deep and .2" long. Some special results occur, such as: fillet combined hardness and case depth tests result in a direct correlation to fatigue life for the crankshafts of diesel engines.


Custom Emat Instrumentation: Correlation Receiver And Flaw Detector, C F. Vasile Jan 1979

Custom Emat Instrumentation: Correlation Receiver And Flaw Detector, C F. Vasile

Review of Progress in Quantitative Nondestructive Evaluation

New, custom instrumentation is presented which is designed to complement and exploit the unique properties of EMAT's. A two channel correlation receiver is described which allows simultaneous detection of the in-phase and quadrature components of an ultrasonic signal with the optimum noise figure and improved interference rejection. In addition, a prototype, fully self-contained EMAT flaw detector is presented. This is a surface wave device for handheld use and incorporates such features as battery operations, correlation detection, search and inspect modes, and digital readout of flaw position and reflected signal amplitude.


A Pseudorandom Binary Noise Ultrasonic System, C M. Elias, T J. Moran Jan 1979

A Pseudorandom Binary Noise Ultrasonic System, C M. Elias, T J. Moran

Review of Progress in Quantitative Nondestructive Evaluation

The random noise ultrasonic system represents the state-of-the-art in terms of sensitivity and resolution for ultrasonic NDE systems. The principle impediment to its use in the field is the lack of real-time inspection capability. If a pair of pseudorandom binary noise sources are substituted for the white noise source in the random noise system, a real-time capability is achieved. An instrument using such sources will be demonstrated and its capabilities will be discussed.


Electrochemical Determination Of Hydrogen In Steel, F Mansfeld Jan 1979

Electrochemical Determination Of Hydrogen In Steel, F Mansfeld

Review of Progress in Quantitative Nondestructive Evaluation

The electrochemical measurement of the permeation r·ate of hydrogen through metal foils consists of charging of the metal with hydrogen on one side of the foil and removal of hydrogen by electrochemical oxidation on the other side. The hydrogen diffusion coefficient can be determined by mathematical analysis of the time dependence of the oxidation current. This electrochemical technique can also be used to determine the hydrogen concentration in metals. For this purpose, an electrochemical cell is placed on the metal to be analyzed and a hydrogen concentration gradient is produced by oxidation of all hydrogen atoms which reach the ...


Ultrasonic Imaging Project And Test Bed, B J. Mckinley Jan 1979

Ultrasonic Imaging Project And Test Bed, B J. Mckinley

Review of Progress in Quantitative Nondestructive Evaluation

This paper describes the Lawrence Livermore Laboratory (LLL) Ultrasonic Imaging Project. The project's purpose is to increase resolution and produce accurate graphic ultrasonic images. Sub projects directed at achieving these goals are: (1) mathematic modeling of elastic wave scattering for realistic defects, (2) developing signal analysis techniques to allow thorough quantitative ultrasonic field measurements, (3) design and fabrication of a high precision, versatile, computer controlled two-transducer ultrasonic test bed with on-line computerized data acquisition, analysis, and image display. Improved methods for quantitative evaluation of bond strength, cracks, and joining are required by current LLL programs. From these requirements the ...


Acoustic Emission Multi-Parameter Analyzer—Aempa, L J. Graham, R Govan, R K. Elsley, G Lindberg, R L. Randall Jan 1979

Acoustic Emission Multi-Parameter Analyzer—Aempa, L J. Graham, R Govan, R K. Elsley, G Lindberg, R L. Randall

Review of Progress in Quantitative Nondestructive Evaluation

A multi-parameter measurement system was designed and built to process signals from acoustic emission (AE) transducers in real time. The system makes selected measurements of each detected AE event as it occurs and stores 23 measured parameters which describe that event in digital form on a standard diskette with IBM format. Measurements recorded on the diskette include information on the shape, magnitude, and frequency content of each AE burst, its timing with respect to location on the specimen under test and its timing with respect to load conditions, pressure, test time, and event count. Over 8000 AE events can be ...


Acoustic Emission Recording Using Nonvolatile Digital Memories, James R. Skorpik Jan 1979

Acoustic Emission Recording Using Nonvolatile Digital Memories, James R. Skorpik

Review of Progress in Quantitative Nondestructive Evaluation

The general trend in acoustic emission (AE) monitoring systems has been one of increasing complexity. This is particularly true in systems for continuous monitoring which are usually multichannel (perhaps 20 to 40) and incorporate a dedicated minicomputer. A unique concept which reverses this trend for selected applications has been developed at Battelle-Northwest, Richland, WA. This concept uses nonvolatile, postage stamp sized solid state digital memories to store acquired data in a permanent form which is easily retrieved. After data has been extracted the memories can be erased and reused. It also uses a fundamental method to accept AE data only ...


Canadian Forces In-Flight Acoustic Emission Monitoring Program, S L. Mcbride Jan 1979

Canadian Forces In-Flight Acoustic Emission Monitoring Program, S L. Mcbride

Review of Progress in Quantitative Nondestructive Evaluation

A crack growing in the forward wing trunnion of a CF100 aircraft was monitored for over 60 flying hours. Acoustic emission data was detected which indicated that during climb, following take-off,the 3mm crack made unstable advances on a few occasions. The detected crack advances produced about 1mm2 of new fracture surface.


Real Tiime Ccd Averager For Ultrasonic Applications, Earl Dunack, William Mccabe Jan 1979

Real Tiime Ccd Averager For Ultrasonic Applications, Earl Dunack, William Mccabe

Review of Progress in Quantitative Nondestructive Evaluation

An ultrasonic acquisition and processing system is being developed which incorporates a real time CCD averager. The averager sums the received ultrasonic signal with the weighted past average to produce the latest average. The averager performance is a function of scan resolution, signal repetition rate, scan velocity, CCD clock rate, weighting value and number of averages desired. The present averager should provide a theoretical improvement in signal to noise of 6 dB. Aside from improving the signal strength at the present scan position the averager is designed such that the signal level from the previous scan location has decayed by ...


New Emat Applications: Ultrasonic Ellipsometer And Detection Of Cracks Under Fasteners, R B. Thompson, C F. Vasile Jan 1979

New Emat Applications: Ultrasonic Ellipsometer And Detection Of Cracks Under Fasteners, R B. Thompson, C F. Vasile

Review of Progress in Quantitative Nondestructive Evaluation

The ability to excite new wave types, such as the horizontally polarized shear (SH) waves, enables EMAT's to perform functions not easily realized with conventional piezoelectric transducers. This paper describes two examples. An ultrasonic ellipsometer is presented which can excite, and detect, shear waves of arbitrary elliptical polarization. It therefore becomes possible to make precision measurements of elastic properties by making direct comparison of the propagation properties of the SH and SV (vertically polarized) components of the wave. The principles of operation are demonstrated by measuring fluid level, a surface property which .produces differential attenuation of the two components ...


Advanced Emat Inspection Systems: Projectiles And Welds, C M. Fortunko, R B. Thompson Jan 1979

Advanced Emat Inspection Systems: Projectiles And Welds, C M. Fortunko, R B. Thompson

Review of Progress in Quantitative Nondestructive Evaluation

EMAT's appear particularly suitable for automated inspection systems because of their ability to operate at high temperatures, at high speed, and without couplant. This paper reviews the progress in two important areas: the high speed inspection of artillery projectiles and high temperature inspection of MIG welds. In each case, material is presented illustrating the system concept and the ease of detection of appropriate flaws. Included is a discussion of the operational characteristics of such systems using SH and SV waves for inspection. The paper also describes the advantages of employing SH waves for volumetric inspection of very thick sections ...


Annular Array Search Units And Their Potential Application In Conventional Ultrasonic Testing Systems, Jerry T. Mcelroy, Kenneth F. Briers Jan 1979

Annular Array Search Units And Their Potential Application In Conventional Ultrasonic Testing Systems, Jerry T. Mcelroy, Kenneth F. Briers

Review of Progress in Quantitative Nondestructive Evaluation

This paper is based on a program to investigate the potential of multi-element annular arrays for practical application in ultrasonic testing systems. The annular array is comprised of coaxially-located, ring-shaped piezoelectric elements. By providing excitation pulses in a spherical time relationship, the transmitted beam may be focused at a specific range. By electronic switching, the focal point can be placed at various distances in the material under examination, Of particular interest is the length over which the beam can be held in collimation. Fabrication methods, delayed excitation techniques, and beam patterns in water and steel are described,


Quantitative Ultrasonic Holographic Defect Characterization, J W. Brophy, A E. Holt, J H. Flora Jan 1979

Quantitative Ultrasonic Holographic Defect Characterization, J W. Brophy, A E. Holt, J H. Flora

Review of Progress in Quantitative Nondestructive Evaluation

Ultrasonic holography has proven to be a useful and accurate tool for defect imaging and sizing in thick wall materials. The optical image formation gives a true two-dimensional cross-section of the flaw as a function of the angle at which the flaw is inspected. Recently Babcock & Wilcox participated in Oak Ridge Laboratories thermal shock program of HSST test vessels, under at EPRI contract, to attempt to define cracks induced into the vessels. The defects induced were "natural" cracks running the length of the vessel.


Automatic Data Recording For Manual Ultrasonic Examinations, A R. Whiting Jan 1979

Automatic Data Recording For Manual Ultrasonic Examinations, A R. Whiting

Review of Progress in Quantitative Nondestructive Evaluation

There exists a need for improving the productivity and reliability of manual ultrasonic examination teams performing PSI or ISI work on nuclear power reactor systems. An analysis of current methods and procedures revealed that the greatest improvement in both areas can be obtained by streamlining data measurement, recording, and reporting. A research and development program for accomplishing this goal is currently near completion. The approach used in this program is to automate the tasks of position measurement and ultrasonic data recording and to use computers for data analysis and reporting. This presentation discusses the automated Search Unit Tracking and Recording ...


Test Bed Concept As A Means Of Introducing New Technology, A L. Thompson, E E. Weismantel, D M. Comassar Jan 1979

Test Bed Concept As A Means Of Introducing New Technology, A L. Thompson, E E. Weismantel, D M. Comassar

Review of Progress in Quantitative Nondestructive Evaluation

The rapid evolution of ultrasonic testing technology over the last ten years has found industry unable to test or apply many of the new concepts resulting from this work due to limited facility resources to adopt these advanced methods. The testing of these methods is a desirable sequence in the evolution of new ideas to production usage and in many cases would require a test bed on which to try innovative ideas. This test bed concept would provide an avenue to resolve applications problems which might otherwise overshadow the significance of technology innovations. The availability of a test vehicle with ...


Overview And Purpose, Anthony G. Evans Jan 1979

Overview And Purpose, Anthony G. Evans

Review of Progress in Quantitative Nondestructive Evaluation

Our purpose in today's session is to discuss procedures for developing accept/reject criteria for NDE methods of inspection. Many of the methods we will describe this morning are not very familiar to members of the audience, so we have deliberately set the session at a fairly leisurely pace so you can assimilate these concepts as they are presented this morning. We would like the session to be relatively informal so we can ask questions and have a fairly extensive discussion period. Following the talks this morning, and after you have had a chance to assimilate some of the ...


Accept/Reject Criteria For Structural Ceramics: Some Effects Of Cavities In The Fracture Of Ceramics - Spherical Cavities, A G. Evans, D R. Biswas, R M. Fulrath Jan 1979

Accept/Reject Criteria For Structural Ceramics: Some Effects Of Cavities In The Fracture Of Ceramics - Spherical Cavities, A G. Evans, D R. Biswas, R M. Fulrath

Review of Progress in Quantitative Nondestructive Evaluation

Fracture probabilities associated with spherical cavities have been analyzed, by combining principles of fracture mechanics and fracture statistics. The analysis considers that fracture occurs from a distribution of cracks located at the cavity surfaces. It predicts effects of cavity size and cavity volume content (porosity) on strength, that depend sensitively on the flaw population vis-a-vis the cavity size distribution. The theory is shown to have limit solutions that coincide with several earlier models of fracture, derived for porous ceramics. The predicted effects of pore size on strength are compared with some available data.


Accept/Reject Criteria For Structural Ceramics: Probablistic Models For Inclusion Initiated Fracture In Ceramics, A G. Evans, B I. Davis, G Meyer, H R. Baumgartner Jan 1979

Accept/Reject Criteria For Structural Ceramics: Probablistic Models For Inclusion Initiated Fracture In Ceramics, A G. Evans, B I. Davis, G Meyer, H R. Baumgartner

Review of Progress in Quantitative Nondestructive Evaluation

Fracture tests on hot-pressed silicon nitride containing several types of inclusions have been conducted. Fracture models pertinent to each inclusion type have been proposed and correlated with the data. The resultant fracture probability relations are one of the key inputs to accept/reject decisions for nondestructive failure prediction.


Accept/Reject Criteria For Structural Ceramics: Some Effects Of Cavities On The Fracture Of Ceramics - Cylindrical Holes, A G. Evans, D R. Biswas, R M. Fulrath Jan 1979

Accept/Reject Criteria For Structural Ceramics: Some Effects Of Cavities On The Fracture Of Ceramics - Cylindrical Holes, A G. Evans, D R. Biswas, R M. Fulrath

Review of Progress in Quantitative Nondestructive Evaluation

The problem of fracture from cylindrical cavities in brittle materials has been analyzed. The analysis is based on the conditions required to extend cracks that pre-exist at the cavity surface. It involves the combined use of fracture mechanics and statistics solutions for crack extension in the concentrated stress field around the cavity. The general pertinence of the approach is substantiated by experimental studies of fracture from cavities in polycrystalline alumina.


Accept/Reject Criteria For Structural Ceramics: A Computer Simulation Of Nondestructive Reliability In Ceramics, G Meyer, K Fertig, J Richardson, A G. Evans Jan 1979

Accept/Reject Criteria For Structural Ceramics: A Computer Simulation Of Nondestructive Reliability In Ceramics, G Meyer, K Fertig, J Richardson, A G. Evans

Review of Progress in Quantitative Nondestructive Evaluation

A computer simulation of nondestructive failure prediction in silicon nitride containing silicon inclusions has been developed. The preliminary application of the simulation examines the results of an inspection that uses a single transducer in the pitch/catch mode. The limitations of the inspection method, especially when applied to nonspherical inclusions, are exposed by the simulation. Also the expected influences of the signal-to-noise ratio and the inclusion size distribution on the fail~re and rejection probabilities emerge from the analysis in quantitative form.


Surface Contamination: Nde Mapping And Effects On Bond Strength, Tennyson Smith Jan 1979

Surface Contamination: Nde Mapping And Effects On Bond Strength, Tennyson Smith

Review of Progress in Quantitative Nondestructive Evaluation

Al 7075-T6 samples have been surface treated by the phospheric acid anodize (PAA) and by the standard FPL etch for comparison. These samples were then deliberately contaminated, bonded and given lap shear or wedge endurance tests to discover the effect of the contamination. The results indicate that the PAA surface is very forgiving of certain types of contamination but not others. The FPL etch surface is sensitive to even a monolayer of contamination. Our NDI surface contamination automatic mapping facility can detect contamination well below the level that significantly degrades the adhesive joints.


Polymer Composite Reliability, David H. Kaelble Jan 1979

Polymer Composite Reliability, David H. Kaelble

Review of Progress in Quantitative Nondestructive Evaluation

The structural performance, reliability and durability of polymer composites can now be correlated with three generic classes of internal defects. The first generic class of chemical structure defects (size 10-100Å) that control critical design properties such as glass transition Tg , moisture absorption, and dimensional changes can be controlled by chemical analysis of raw materials prior to manufacture. A second generic class of manufacturing defects (size greater than l0μm) include inclusions, voids and debonds which are related to manufacturing process control and recognized by ultrasonics, optical scanning and other techniques sensitive to interfacial imperfections. The interaction of these two classes ...


The Impact Of Inspection And Analysis Uncertainty On Reliability Prediction And Life Extension Strategy, Charles A. Rau Jr Jan 1979

The Impact Of Inspection And Analysis Uncertainty On Reliability Prediction And Life Extension Strategy, Charles A. Rau Jr

Review of Progress in Quantitative Nondestructive Evaluation

Life extension of high cost components until measurable damage is detected can result in marked reductions in total cycle costs. The life extension strategy for turbine disks is based upon nondestructive inspection to detect defects, usage and stress analysis to define requirements, and fracture mechanics analysis and testing to evaluate the severity of any defects under future usage. Because there are uncertainties and inaccuracies in the inspection, analysis, testing and definition of past and future usage, the selection of the optimum life extension strategy requires quantitative evaluation of the costs and risks associated with each uncertainty during life extension. This ...


Ultrasonic Evaluation Of Adhesive Bond Strength Using Spectroscopic Techniques, F H. Chang, R A. Kline, J R. Bell Jan 1979

Ultrasonic Evaluation Of Adhesive Bond Strength Using Spectroscopic Techniques, F H. Chang, R A. Kline, J R. Bell

Review of Progress in Quantitative Nondestructive Evaluation

In this program statistical analysis of ultrasonically determined parameters was used to identify the features of acoustic wave propagation in adhesively bonded structures which could be used to determine adhesive bond strength. The parameters associated with the interaction of ultrasonic waves with the adhesive-aluminum interfaces and adhesive interlayer which were investigated included bondline transit time, amplitude ratios of reflections from the various interfaces, frequency dependent attenuation and spectral resonance characteristics. Aluminum specimens with both etched and as-received surface preparation were studied. The capabilities of the Fokker bondtester for adhesive strength determination were also assessed. Adaptive learning techniques were used to ...


Characterization Of Defects In Adhesive Bonds By Adaptive Learning Networks, Anthony N. Mucciardi, R K. Elsley Jan 1979

Characterization Of Defects In Adhesive Bonds By Adaptive Learning Networks, Anthony N. Mucciardi, R K. Elsley

Review of Progress in Quantitative Nondestructive Evaluation

Broadband ultrasonic pulses reflected from adhesively bonded structures have been used to train adaptive learning networks (ALN) to identify flawed regions of these structures. The goal is to identify four different types of flaws.


Moisture Diffusion Analysis For Composite Microdamage, C L. Leung Jan 1979

Moisture Diffusion Analysis For Composite Microdamage, C L. Leung

Review of Progress in Quantitative Nondestructive Evaluation

The absorption of moisture into fibrous polymeric meterials has been recognized as one of the major mechanisms in the strength degradation of such materials as reported by several workshops (1-3) and publications (4-7). The objective of the work reported here is to use nondestructive evaluation (NDE) techniques to determine the moisture content (profile) within a composite by measuring the w~isture diffusion rate and then subjecting the data to a statistical estimation analysis. This reveals the location of structural degradation and provides a sensitive inspection method for the serviceability of composites. Hydrothermal aging effects on cured graphite-epoxy composites were determined ...


Microwave Nde Of Ceramics, A J. Bahr Jan 1979

Microwave Nde Of Ceramics, A J. Bahr

Review of Progress in Quantitative Nondestructive Evaluation

The objective of this work is to evaluate the potential of microwave techniques for detecting, classifying, and determining the dimensions of inclusions and surface cracks in structural ceramics such as Si3N4. Experimental results that show the feasibility of detecting various types of inclusions and voids in Si3N4 have been obtained, and these results are reviewed. In addition, the question of the quantitative capability of microwave NDE for this application is discussed.


Ultrasonic Measurement Of Interfacial Properties In Completed Adhesive Bonds, George A. Alers, R K. Eksley, John M. Richardson, K Fertig Jan 1979

Ultrasonic Measurement Of Interfacial Properties In Completed Adhesive Bonds, George A. Alers, R K. Eksley, John M. Richardson, K Fertig

Review of Progress in Quantitative Nondestructive Evaluation

The problem of detecting weak adhesion in completed adhesive bonds can be considered a problem in measuring the effective acoustic impedance of a thin layer at the adherend to adhesive interface. By calculating the ultrasonic reflection coefficient of the entire sandwich structure as a function of frequency including an interfacial layer, it can be shown that quite obvious changes in the reflection spectrum can be produced by minor changes in the properties of the thin layer. The inverse problem of deducing the properties of the thin layer from experimental measurements is more difficult because of the sensitivity of the results ...


Flaw Detection And Characterization In Ceramics With The Scanning Laser Acoustic Microscope (Slam), D E. Yuhas, L W. Kessler Jan 1979

Flaw Detection And Characterization In Ceramics With The Scanning Laser Acoustic Microscope (Slam), D E. Yuhas, L W. Kessler

Review of Progress in Quantitative Nondestructive Evaluation

The high resolving power coupled with the real time capability of the SLAM make it a useful technique for characterization of materials including ceramics. The elastic structure of·ceramics is often dependent upon the details of the fabrication process, e.g., sintering, hot pressing, amount of. binder, etc .. Accordingly, acoustic micrographs and acoustic interferograms which reveal characteristic sonic transmission patterns and sonic velocity variations, respectively, can be used to nondestructively evaluate ceramics to ensure material uniformity. In addition, the ability to nondestructively detect flaws and inclusions is important in fracture toughness studies and in the evaluation of finished components.