scispace - formally typeset
Search or ask a question

Showing papers in "Strain in 1986"


Journal ArticleDOI
01 Feb 1986-Strain
TL;DR: In this paper, the authors developed a highly sensitive instrument for full field experimental stress analysis, called SPATE, which is used for structural materials and engineering components at NEL, and techniques have been developed to extend the instrument to wide band random loading applications.
Abstract: Recent advances in infra-red technology have permitted SIRA Ltd to develop a highly sensitive instrument for full field experimental stress analysis. The calibration and performance of this instrument (SPATE) is being evaluated on a wide range of structural materials and engineering components at NEL, and techniques have been developed to extend the instrument to wide band random loading applications. SPATE has proved to be a very successful and convenient instrument for performing non-contacting experimental stress analysis on full scale engineering structures, and its extension to random loading conditions using specially developed signal processing software has produced a completely unique facility at NEL.

25 citations


Journal ArticleDOI
01 Feb 1986-Strain
TL;DR: In this article, a laser Doppler system is described using photon correlation signal analysis with a microcomputer control, which can be used to measure velocities in sound waves, and the free field infront of a loudspeaker has been measured to show both spatial and temporal variations.
Abstract: A laser Doppler system is described using photon correlation signal analysis with a microcomputer control, which can be used to measure velocities in sound waves. The free field infront of a loudspeaker has been measured to show both spatial and temporal variations. Comparisons with velocities predicted from loud level recordings show close agreement.

13 citations


Journal ArticleDOI
01 Aug 1986-Strain
TL;DR: In this article, the authors introduced recent developments achieved in China regarding the centre hole relaxation technique for residual stress measurement and described a special device developed by the author for the small blind hole drilling and measuring.
Abstract: The paper introduces recent developments achieved in China regarding the centre hole relaxation technique for residual stress measurement. A special device developed by the author for the small blind hole drilling and measuring is described. Some examples of application of this method by using this special device are given. They include stress measurement of: (i) Stiffened top flange of the test section of a railway steel box girder bridge. (ii) The butt weld joints of the ‘15 MnVNi’ alloy steel thick plates. (iii) The welded side frames of a diesel locomotive.

9 citations


Journal ArticleDOI
01 Feb 1986-Strain
TL;DR: In this article, the authors evaluate the validity of expressions for calculating the shift in the value of Poisson's ratio, from its theoretical elastic value to its plastic value, as a function of strain.
Abstract: Poisson's ratio has been measured in solution annealed stainless steel type 316, under elastic and plastic deformation, using Moire interferometry. The aim of the study was to evaluate the validity of expressions for calculating the shift in the value of Poisson's ratio, from its theoretical elastic value to its plastic value, as a function of strain.

9 citations


Journal ArticleDOI
01 May 1986-Strain
TL;DR: In this article, the interaction of the photoelastic parameters, the normalised light intensity In the characteristic angle ψ, and their link to the stress state parameters, such as the ratio of bending and direct stresses P and the angle of divergence θ of the stress components σM and σN have been examined by employing different wavelengths.
Abstract: The interaction of the photoelastic parameters, the normalised light intensity In the characteristic angle ψ, and their link to the stress state parameters, the ratio of bending and direct stresses P and the angle of divergence θ of the stress components σM and σN have been examined by employing different wavelengths. The analysis of the experimental data shows that the correlation diagrams of these parameters demonstrate similar characteristic curves. Measurements also show a preferable range of wavelength within which the wavelength of light source should be selected. So far the results are valid for thin plates, thin shells of rotationally symmetric conditions and similar structures.

4 citations


Journal ArticleDOI
01 Nov 1986-Strain
TL;DR: In this paper, various types of calibrations have been carried out to identify the errors associated with these differences and the results show that, provided the manufacturers' recommendations are adhered to, the errors are acceptably small.
Abstract: CEGB-Planer capacitance strain gauges are used extensively for monitoring the deformation of components operating in the creep range. However, there are significant differences between the way the gauges are installed for use and the way they are installed for calibration. This paper describes the various types of calibrations that have been carried out to identify the errors associated with these differences and the results show that, providing the manufacturers' recommendations are adhered to, the errors are acceptably small.

4 citations


Journal ArticleDOI
01 Aug 1986-Strain
TL;DR: In this paper, stress separation on a tooth of a timing belt by two approaches to the shear difference method was performed by approximating the composite belt to a non-homogeneous body made up of two distinctly different homogeneous isotropic materials.
Abstract: Using a birefringent coating technique, stress separation is carried out on a tooth of a timing belt by two approaches to the shear difference method. The analysis is performed by approximating the composite belt to a non-homogeneous body made up of two distinctly different homogeneous isotropic materials. The results from the two approaches are found to be in very close agreement.

2 citations


Journal ArticleDOI
01 May 1986-Strain
TL;DR: In this article, the authors compared the results from the centre hole and the parting out techniques and a fully penetrant bead on plate fatigue sample with the bead running axially was used to compare the two techniques in more detail.
Abstract: Residual stress determination has been carried out on production welds to provide engineering data. A parting out technique has been used in which a strain gauged through thickness slug of material is removed from the weld area. The centre hole technique has been used with the blind hole in the weld material. There were differences between the results from the two techniques and a fully penetrant bead on plate fatigue sample with the bead running axially was used in order to compare the two techniques in more detail. After parting out, the layer removal technique was carried out in order to provide a relatively detailed through thickness residual stress distribution in order to explain the differences between the results from the centre hole and parting out techniques.

1 citations


Journal ArticleDOI
01 Aug 1986-Strain
TL;DR: In this paper, various types of commercial strain gauges have been evaluated to determine the most appropriate installation for severe applications and the best results were obtained using a constantan metal foil element strain gauge with phenolic glass backing.
Abstract: Strain gauges are used extensively to measure the changes in magnitude and distribution of dynamic stresses during fatigue testing. Over 200 000 fatigue cycles at high strains (4000 ± 2000/u/m) have to be withstood under certain conditions such as when evaluating the performance of heavy vehicle springs. In this work, various types of commercial strain gauges have been evaluated to determine the most appropriate installation for severe applications. The best results were obtained using a constantan metal foil element strain gauge with phenolic glass backing. Tests on heavy vehicle, multi-leaf, Taperlite springs, manufactured by Tinsley Bridge Limited (formerly BSC Light Products), have demonstrated the suitability of the chosen system and showed that the dynamic stresses remained essentially constant during fatigue testing.

1 citations


Journal ArticleDOI
01 Aug 1986-Strain
TL;DR: In this paper, the practical aspects of photography, exposure variations and evaluation are treated in two parts: photographic methods and application to isochromatics, Part 2 evaluation and calibration for fractional orders with examples, application of isoclinics and a summary of main features.
Abstract: Sharp boundaries or thin lines seen on high contrast or Agfacontour photographs of optical fringes are interpreted as equidensity lines and calibrated for fractional order or isoclinic angle. Systematic variation of exposure determinants changes their positions and parameters so that the entire photographed field can be evaluated from sets of photographs either taken directly or copied from one or a few low contrast negatives. Photogrammetry resolves spatial detail down to 0002mm spot size and relates photoelastic results to model outlines and deformation measured on the same films. The practical aspects of photography, exposure variations and evaluation are treated in this overview published in two parts. Part 1 covers photographic methods and application to isochromatics, Part 2 evaluation and calibration for fractional orders with examples, application to isoclinics and a summary of main features.

Journal ArticleDOI
01 Feb 1986-Strain
TL;DR: In this article, a suggested range of standards and codes of practice is described, from the anticipated BSI Standard on Strain Gauge Calibration to a proposed standard on strain gauge application and possible specifications on instrumentation for static and dynamic measurement.
Abstract: Strain measurement techniques are being used more frequently today to check that manufactured components are at a safe stress level in service. Designers are also requiring strain gauge tests on prototypes to confirm that the theoretical calculations are realistic and designs are economic. Against this background the measurement engineer finds himself under pressure to produce test results quickly and sometimes to justify them. Strain measurement standards would have an important role in convincing customers that tests have been carried out in an approved manner and could be the measurement engineer's defence in the case of disputed results. A suggested range of standards and codes of practice is described, from the anticipated BSI Standard on Strain Gauge Calibration to a proposed standard on strain gauge application and possible specifications on instrumentation for static and dynamic measurement. The need for strain measurement technician training and possible participationin the National Testing Laboratory Accreditation Scheme, NATLAS, is also discussed.

Journal ArticleDOI
Majid Kabiri1
01 May 1986-Strain
TL;DR: The construction of Mohr's circle for measurement of residual strains in thin plates by the Hole Drilling Method is described in this article. But the relative errors in determining the location of the centre and the radius of Mohrin's circle due to ignoring the effect of transverse sensitivity are calculated.
Abstract: The construction of Mohr's circle for measurement of residual strains in thin plates by the Hole Drilling Method is described. The relative errors in determining the location of the centre and the radius of Mohr's circle due to ignoring the effect of transverse sensitivity are calculated. For normal gauges with low cross sensitivity, these errors are shown to be negligible (less than 1%).

Journal ArticleDOI
01 Nov 1986-Strain
TL;DR: In this paper, the application of strain gauges to determine the stress on wet and porous media such as rock has been examined, and the bonding and the stability of the gauges under load in water have been examined.
Abstract: The application of strain gauges to determine the stress on wet and porous media such as rock has been examined. Weldable strain gauges have not been considered. Special consideration has been. given to different methods of water protection. For unbonded strain gauges tested under water a logarithmic dependence between time and resistivity has been found. Several kinds of moisture protection have been tried on the material side as well as on the back side of selected strain gauges. The bonding and the stability of the gauges under load in water has been examined.