Deformation and fracture of particulate epoxy in adhesive bonds
- Tel-Aviv Univ. (Israel). Dept. of Mechanics
The effect of bond thickness, t, on the fracture behavior of two epoxy adhesives toughened by a wide range of particle size, distribution and hardness was evaluated using DCB type test specimens. Video recording and scanning electron microscopy were used to study the damage evolution and the post-fracture morphology in the bond. The stress-strain behavior in shear was determined for a limited number of bond thicknesses using the napkin ring test specimen. Similarly to previous findings on homogeneous polymeric adhesives, G{sub IIC} and G{sub IIIC} coincided irrespective of t. Moreover, the opening and the shearing fracture energies converged to a common value when t was decreased to the micrometer range. New trends were found, however, when t approached the reinforcement size. A predominant feature of the crack propagation in this case was coalescence of voids that originated from particles ahead of the crack tip. The relief of hydrostatic stress caused by this damage is believed to be responsible for the alteration of the mode I fracture behavior as compared to homogeneous adhesives. The stiffness of the reinforcement particles played an important rule on the fracture in shear.
- OSTI ID:
- 89797
- Report Number(s):
- CONF-9409291--; ISBN 1-56676-220-0
- Country of Publication:
- United States
- Language:
- English
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