The Viscoelastic Shear Behavior of a Structural Adhesive
The increased use of adhesives in the automobile, aerospace and other industries is noted. The need to understand the viscoelastic nature of polymeric adhesives is assessed. Previous bulk tensile constant strain-rate, creep, relaxation, and delayed failures studies on an epoxy adhesive are summarized. New constant strain-rate and creep data for symmetric rail shear and symmetric lap shear geometries of the same epoxy adhesive are reported. It is shown that significant viscoelastic shear behavior, including delayed failures, do occur. The linear viscoelastic methods and results from previous tensile studies are extended to the condition of shear. Predictions are shown to be at variance with experimental results. The reasons for deviations are discussed; i.e., the possibility that linear viscoelastic analytical procedures are inappropriate and the likelihood that viscoelastic phenomena are different in bulk tensile, bulk shear and lap shear geometries.
KeywordsCrack Opening Displacement Crack Opening Displacement Epoxy Adhesive Shear Property Structural Adhesive
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- 2.M.P. Renieri, C.T. Herakovich, and H.F. Brinson, “Rate and Time Dependent Behavior of Structural Adhesives”, VPI Report, VPI-E-76-7, April 1976.Google Scholar
- 3.H.F. Brinson, “The Viscoelastic-Plastic Characterization of a Ductile Polymer”, Deformation and Fracture of High Polymers, H. Kausch, et al., eds. Plenum Press, NY, 1974.Google Scholar
- 7.M.J. Crochet, “Symmetric Deformations of Viscoelastic-Plastic Cylinders”, J. of Appl. Mech., 33, p. 326, 1966.Google Scholar
- 8.M. Reiner, Advanced Rheology, H.K. Lewis and Co. Ltd., London, 208, 1971.Google Scholar
- 12.Y.T. Yeow and H.F. Brinson, “A Comparison of Simple Shear Characterization Methods for Composite Laminates”, Composites. Jan. 1978.Google Scholar
- 13.W.J. Renton and J.R. Vinson, “Shear Property Measurements of Adhesives in Composite Material Bonded Joints”, ASTM-STP 580, 1974.Google Scholar
- 14.E. Sancaktar, “The Viscoelastic Shear Behavior of Adhesives”, Ph.D. Thesis, VPI & SU, June 1979.Google Scholar
- 15.A.V. Tobolsky, Properties and Structure of Polymers, J. Wiley & Sons, Inc., NY, 1960.Google Scholar
- 16.J.S. Cartner, Jr., “The Nonlinear Viscoelastic Behavior of Adhesives and Chopped Fiber Composites”, M.S. Thesis, VPI & SU August 1978.Google Scholar