Abstract
Optical interferometry is used to measure crackopening profiles for interfacial cracks in a model adhesive joint. Application of boundary displacements with a resolution of 0.16 μm is achieved through a combination of thermal expansions and optical control in a servo loop. The degree of nonlinear deformation accompanying small levels of normal and shear strain across the bond is documented, and crackfront displacement fields are exploited to evaluate possible criteria for crack growth under combined normal and shear loading. Within the accuracy afforded by the crack-propagation investigation it appears that crack growth is governed by the vectorial crack-tip displacements, namely by the vector sum of the local normal and tangential displacement components. In the limit of infinitesimal strains this criterion reduces to the strain energy-release-rate criterion of linear fracture mechanics.
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References
Knauss, W.G., On the Steady Propagation of a Crack in a Viscoelastic Sheet: Experiments and Analysis,” Deformation and Fracture of High Polymers, ed. by Kaush, Hassel and Jaffee, Plenum Press (1973).
Wang, S.S. and Yau, J.F., “An Analysis of Interface Crack in Adhesively Bonded Lap Shear Joints,” Modern Development in Composite Materials and Structures, ed. by J.R. Vinson, ASME, 67–83 (1979).
Liechti, K.M., “The Application of Optical Interferometry to Time Dependent Unbonding,” PhD Thesis Cal. Instit. of Tech. (May 1980).
Liechti, K.M. andKnauss, W.G., “Crack Propagation at Material Interfaces: I. Experimental Techniques to Determine Crack Profiles,”Experimental Mechanics,22 (7),262–269 (July1982).
Comninou, M. andSchmueser, D., “The Interface Crack in a Combined Tension-Compression and Shear Field,”J. Appl. Mech.,46,345–348 (1979).
Knauss, W.G. and Mueller, H.K., “The Mechanical Characterization of Solithane 113 in the Swollen and Unswollen State,” Caltech, GALCIT SM 67-8, Pasadena, CA (Dec. 1967).
Knowles, J.K. andSternberg, E., “On the Singularity Induced by Certain Mixed Boundary Condition in Linearized and Nonlinear Elastostatics,”Int. J. Solids and Struct.,11,1173 (1975).
Shih, C.F., deLorenzi, H.G. and Andrews, W.R., “Studies on Crack Initiation and Stable Crack Growth,” Elastic-Plastic Fracture, ASTM STP 668, ed. by J.D. Landes, J.A. Begley and G.A. Clarke, ASTM, 65–120 (1979).
Kanninen, M.F., et al., “Elastic-Plastic Fracture Mechanics for Two-Dimensional Stable Crack Growth and Instability Problems,” Elastic-Plastic Fracture, ASTM STP 688, ASTM, 121–150 (1979).
Achenbach, J.D., Keer, L.M., Khetan, R.P. andChen, S.H., “Loss of Adhesion at the Tip of an Interface Crack,”J. of Elasticity,9,397–424 (1979).
Rice, J.R. andShih, G.C., “Plane Problems of Cracks in Dissimilar Media,”J. Appl. Mech.,32,418–423 (1965).
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Liechti, K.M., Knauss, W.G. Crack propagation at material interfaces: II experiments on mode interaction. Experimental Mechanics 22, 383–391 (1982). https://doi.org/10.1007/BF02325405
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DOI: https://doi.org/10.1007/BF02325405