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Showing papers in "Strain in 1968"


Journal ArticleDOI
01 Apr 1968-Strain
TL;DR: In this paper, the hole drilling method is used to evaluate bi-axial residual stresses varying with depth, and the results show that the method can be used on large structures and in field conditions.
Abstract: The hole drilling method is used to evaluate bi-axial residual stresses varying with depth. Equations with experimentally determined calibration constants, given here for light-alloys, relate residual stresses to strain relaxations as the hole is drilled. Accuracy and limitations are assessed by application to known stress conditions. The method can be used on large structures and in field conditions.

39 citations


Journal ArticleDOI
01 Jul 1968-Strain
TL;DR: A program for interpreting Moire fringe data using a digital computer is described in this article, where the finite element technique overcomes certain intrinsic defects of existing methods which use polynomials, and promises to give better results, especially where stress concentrations are present.
Abstract: A program for interpreting Moire fringe data using a digital computer is described. The finite element technique overcomes certain intrinsic defects of existing methods which use polynomials, and promises to give better results, especially where stress concentrations are present. An experimental example compares the technique with the polynomial technique.

34 citations


Journal ArticleDOI
01 Jul 1968-Strain

10 citations


Journal ArticleDOI
01 Jan 1968-Strain
TL;DR: In this article, a region of the test piece where stresses or strains are known may serve as a compensator, and if the test strains, elastic or non-elastic, are required and the elastic compensating strain is known, Poisson's ratio of the compensator enters into the evaluation.
Abstract: If gauges or rosettes identical with those used in testing are affixed to a compensating bar under known stresses and of the same material as the test piece, the required stresses are obtained directly in terms of the known compensating stress and of the measured resistance changes. Cross-sensitivity, gauge factor and constants of elasticity of the test piece cancel out and errors due to inaccurate assumptions for their values are avoided. If the test strains, elastic or non-elastic, are required and the elastic compensating strain is known, Poisson's ratio of the compensator enters into the evaluation. A region of the test piece where stresses or strains are known may serve as a compensator. One compensating rosette or two single compensating gauges suffice for any number of identical testing gauges. Initial zero balance may not always be needed and special circuits facilitate evaluation, which lends itself to simple self-contained automation. An analogue unit suggested for incorporation in a strain meter allows direct display of principal stresses and directions from rosette measurements.

8 citations


Journal ArticleDOI
01 Apr 1968-Strain
TL;DR: In this paper, the start up of a power station is measured by weldable gauges consisting of two longitudinal and two transverse Nichrome foil grids on a rectangular steel shim spot-welded to the turbine casing along a central line of the shim.
Abstract: Transient thermal strains daring start up of power station plants are measured by weldable gauges consisting of two longitudinal and two transverse Nichrome foil grids on a rectangular steel shim spot-welded to the turbine casing along a central line of the shim. Performance tests and results are described for these ganges.

5 citations


Journal ArticleDOI
01 Oct 1968-Strain

4 citations


Journal ArticleDOI
01 Jan 1968-Strain
TL;DR: In this paper, a monochromatic slit source is used to illuminate a line amplitude grating and a transparent speciment is interposed between the slit and the grating.
Abstract: A simple method is presented for measuring partial slopes of transparent specimens in plane stress. A monochromatic slit source is used to illuminate a line amplitude grating and the transparent specimen is interposed between the slit and the grating. The deformed lateral surfaces of the loaded speciment distort the lines of the grating and yield contours of equal partial slope of the specimen in a direction normal to the direction of the rulings of the grating. The method is used for determining the magnitude and gradients of the sum of principal stresses in plane elastic problems.

4 citations


Journal ArticleDOI
01 Oct 1968-Strain
TL;DR: In this paper, the behaviour of various strain gauges on unstressed aluminium under various heating rates is investigated systematically, and various gauge installation, gauge preparation, evaluation of tests and results are presented.
Abstract: The behaviour of various strain gauges on unstressed aluminium under various heating rates is investigated systematically. Testing installations, gauge preparation, evaluation of tests and results are presented.

4 citations


Journal ArticleDOI
01 Apr 1968-Strain

2 citations



Journal ArticleDOI
01 Jan 1968-Strain
TL;DR: In this paper, the authors report work on embedded resistance strain gauges mounted on concrete and other forms of gauge carrier, techniques for strain gauging embedded steelwork, results of gauge factor tests on briquetted and unbriquetted vibrating wire gauges, and gauge responses to temperature variations.
Abstract: Methods of strain measurement in concrete have been investigated experimentally. This paper reports work on embedded resistance strain gauges mounted on concrete and other forms of gauge carrier, techniques for strain gauging embedded steelwork, results of gauge factor tests on briquetted and unbriquetted vibrating wire gauges, and gauge responses to temperature variations. Proposals are outlined for future work particularly on stress meters as distinct from strain gauges.


Journal ArticleDOI
01 Apr 1968-Strain
TL;DR: A creep gauge based on a differential transformer and mechanical magnification measures a diametral expansion of less than 0-1X10-6 in/in per hour on a 5 in diameter tube at 300 deg. C in a reactor environment as discussed by the authors.
Abstract: A creep gauge based on a differential transformer and mechanical magnification measures a diametral expansion of less than 0-1X10-6 in/in per hour on a 5 in diameter tube at 300 deg. C in a reactor environment.

Journal ArticleDOI
01 Apr 1968-Strain
TL;DR: In this article, a procedure for calculating the gauge factor for strain measurement on a given test material at a known temperature is given, and results of experiments on suitable instrumentation are presented.
Abstract: Characteristics of semiconductor strain gauges are explored experimentally and a procedure is given for calculating the gauge factor for strain measurement on a given test material at a known temperature. Results of experiments on suitable instrumentation are presented.


Journal ArticleDOI
01 Oct 1968-Strain
TL;DR: Commercial Ultra-High-Speed Cameras for framing rates over 50,000 f.p.s. are very expensive and yield a small number of frames per run, but the single-flash technique with increasing delays gives photographs at a high framing rate over a comparatively long time and, as described here, requires no special electronic equipment except a good flash unit and a general-purpose oscilloscope.
Abstract: Commercial Ultra-High-Speed Cameras for framing rates over 50,000 f.p.s. are very expensive and yield a small number of frames (8 to 24) per run. The single-flash technique with increasing delays gives photographs at a high framing rate over a comparatively long time and, as described here, requires no special electronic equipment except a good flash unit and a general-purpose oscilloscope.


Journal ArticleDOI
H. M. Haydl1
01 Jul 1968-Strain