Experimental Mechanics

, Volume 52, Issue 8, pp 1151–1161 | Cite as

A New Shear-Compression Test for Determining the Pressure Influence on the Shear Response of Elastomers

Article
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Abstract

A new shear-compression experiment for investigating the influence of hydrostatic pressure (mean stress) on the large deformation shear response of elastomers is presented. In this new design, a nearly uniform torsional shear strain is superposed on a uniform volumetric compression strain generated by axially deforming specimens confined by a stack of thin steel disks. The new design is effective in applying uniform shear and multiaxial compressive stress on specimens while preventing buckling and barreling during large deformation under high loads. By controlling the applied pressure and shear strain independently of each other, the proposed setup allows for measuring the shear and bulk response of elastomers at arbitrary states within the shear-pressure stress space. Thorough evaluation of the new design is conducted via laboratory measurements and finite element simulations. Practical issues and the need for care in specimen preparation and data reduction are explained and discussed. The main motivation behind developing this setup is to aid in characterizing the influence of pressure or negative dilatation on the constitutive shear response of elastomeric coating materials in general and polyurea in particular. Experimental results obtained with the new design illustrate the significant increase in the shear stiffness of polyurea under moderate to high hydrostatic pressures.

Keywords

Polyurea Viscoelastic Time–pressure superposition WLF equation Confined test 
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Notes

Acknowledgement

The authors wish to thank Dr. Roshdy Barsoum of the Office of Naval Research through his guidance and cooperation and for the sustained support of this difficult effort under Grant ONR N000 14-09-1-0552 and ONR N000 14-11-1-0390.

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Copyright information

© Society for Experimental Mechanics 2011

Authors and Affiliations

  1. 1.Graduate Aerospace LaboratoriesCalifornia Institute of TechnologyPasadenaUSA

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