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Experimental Mechanics

, Volume 5, Issue 6, pp 167–176 | Cite as

The moiré-fringe method of displacement measurement applied to indirect structural-model analysis

Authors indicate that the results of experimental model-analysis technique compare satisfactorily with those derived from theoretical analysis
  • R. Shepherd
  • L. Mc D. Wensley
Article

Synopsis

The production of moiré fringes when one grid of equally spaced lines is moved relative to a second similar grid is a well known phenomenon. These fringes may be used to measure the displacements of a transparent structural model if one set of lines is attached to the model and a second set is fixed to a transparent reference screen.

The indirect method of model analysis of structures entails the determination of the influence line for a force or moment at a section in the structure from accurate observations of the displacements of the model which occur when a chosen deformation is applied at the particular section under consideration.

This paper describes the successful application of the moiré-fringe method of displacement measurement to indirect structural-model analysis.

Keywords

Mechanical Engineer Fluid Dynamics Indirect Method Displacement Measurement Accurate Observation 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

List of Symbols

F.O.

fringe order

G

span ratio

H

horizontal force Subscripts refer to position of application

M

moment Subscripts refer to position of application

V

vertical force Subscripts refer to position of application

h

distance between adjacent line

s

distance between adjacent fringes

δH

applied horizontal displacement

δV

applied vertical displacement

\(\delta _\phi \)

applied rotational displacement

θ

acute angle between two sets of lines

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References

  1. 1.
    Weller, R., andShepard, B. M., “Displacement Measurement by Mechanical Interferometry,”Proc. Soc. Exptl. Stress Anal., VI (1),35–39 (1948).Google Scholar
  2. 2.
    Durelli, A. J., and Daniel, I. M., “Structural Model Analysis by means of Moiré Fringes.Proc. A.S.C.E.,86 (ST 12), (Dec. 1960).Google Scholar
  3. 3.
    Beggs, G. E., “An Accurate Mechanical Solution of Statically Indeterminate Structures by use of Paper Models and Special Gauges,”Proc. A.C.J., 18, 58–82 (1922).Google Scholar
  4. 4.
    Eney, W. J., “A Large Displacement Deformeter Apparatus for Stress Analysis with Elastic Models,”Proc. Soc. Exptl. Stress Anal., VI (2),84–93 (1948).Google Scholar
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    Hetenyi, M., “Handbook of Experimental Stress Analysis,”Wiley & Co., New York, 665–667 (1950).Google Scholar
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    Charlton, T. M., “Model Analysis of Structures,”E. and F. N. Spon, Ltd., London (1954).Google Scholar
  7. 7.
    Wensley, L. McD., “The Moiré Method of Determining Displacements in Structural ModelsUnpublished M.E. Thesis, Univ. of Canterbury, New Zealand (1963).Google Scholar

Copyright information

© Society for Experimental Mechanics, Inc. 1965

Authors and Affiliations

  • R. Shepherd
    • 1
  • L. Mc D. Wensley
    • 2
  1. 1.Civil EngineeringUniversity of CanterburyChristchurchNew Zealand
  2. 2.Moir, New & Jenkins, Consulting EngineersInvercargillNew Zealand

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