Skip to main content
SpringerLink
Log in

Strain-ratio measurements by an interferometric device

The lateral strains which result during tensile testing can be accurately measured using a simple Fabry-Perot interferometric device located directly on the specimen

  • Published:
Experimental Mechanics Aims and scope Submit manuscript

Abstract

An interferometric experimental device capable of measuring lateral strains with a sensitivity of 5×10−6 is described. The results of lateral and axial strain measurements during creep and isochronous tests on polymethyl-methycrylate (PMMA) are presented, and values for strain ratio (the ratio of lateral to axial strains) are calculated. The values display excellent repeatibility and are within the range of values recently published in the literature.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

Abbreviations

h :

interferometer plate separation

I :

intensity of interfering light

I 0 :

intensity of illuminating beam

k :

integer fringe order

p :

uncertainty in intensity reading

Q :

resonator quality

R 1 :

reflectivity of semitransparent mirror

R 2 :

reflectivity of fully reflecting mirror

δ:

fractional fringe order

ε:

angle of incidence

λ:

wavelength of light (0.63 μm for He−Ne laser)

ψ:

phase difference

References

  1. McCammond, D. andBenham, P. P., “A Study of Design Stress Analysis Procedures for Thermoplastic Components Using Time-dependent Data,”Plastics & Polymers,37,475, (1969).

    Google Scholar 

  2. Lethersich, W., “A Precise Extensometer and its Use for the Measurement of Poisson's Ratio,”J. Sci. Ins.,21,180, (1944).

    Article  Google Scholar 

  3. Carmichael, A. J., “Volume Changes in Polyethylene During Plastic Deformation,”Aust. J. Appl. Sci.,15,289 (1964).

    Google Scholar 

  4. Lobdell, A. J., Shinopulus, G. F. andFillio, D. N., “An Instrument to Measure Transverse Strain,”Matl. Res. & Stds.,4,8, (1964).

    Google Scholar 

  5. Benham, P. P. andMcCammond, D., “Studies of Creep and Contraction Ratio in Thermoplastics,”Plastics and Polymers,39,130, (1971).

    Google Scholar 

  6. Mallon, P., McCammond, D. andBenham, P. P., “Strain Ratio and Volume Change During Tension and Compression Creep of Thermoplastics,”Poly. Eng. Sci.,12,420, (1972).

    Article  Google Scholar 

  7. Ladizesky, N. H. andWard, I. M., “Determination of Poisson's Ratio and Young's Modulus of Low-density Polyethylene,”J. Macromol. Sci., B 5,661, (1971).

    Google Scholar 

  8. Powers, J. M. andCadell, R. M., “The Microscopic Volume Changes of Selected Polymers Subjected to Uniform Tensile Deformation,”Poly. Eng. Sci.,12,432, (1972).

    Article  Google Scholar 

  9. Hoff, E. A. W., unpublished results.

  10. Bonnin, M. J., Dunn, C. H. R. andTurner, S., “A Comparison of Torsional and Flexural Deformations in Plastics,”Plastics and Polymers,37,517, (1969).

    Google Scholar 

  11. McCammond, D. andTurner, S., “Poisson's Ratio and the Deflection of a Viscoelastic Plate,”Poly. Eng. Sci.,13,187 (1973).

    Article  Google Scholar 

  12. Turner, S. and Wills, W. H., “Tensile Creep Testing of Plastics,” Symp. on Development in Mat. Testing Machine Design, SEE and I. Mech. E., Manchester (1965).

  13. Steel, W. H., “Interferometry,”Cambridge Univ. Press, England (1967).

    Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Mechanical Engineering Dept., University of Toronto, Toronto, Canada

    D. McCammond (Assistant Professor) & J. Motycka (Director of Laboratories)

Authors
  1. D. McCammond
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. J. Motycka
    View author publications

    You can also search for this author in PubMed Google Scholar

Rights and permissions

Reprints and permissions

About this article

Cite this article

McCammond, D., Motycka, J. Strain-ratio measurements by an interferometric device. Experimental Mechanics 14, 225–229 (1974). https://doi.org/10.1007/BF02323322

Download citation

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF02323322

Keywords

Search

Navigation