A Photoelastic Investigation into the Effects of Cracks and Boundary Conditions on Stress Intensity Factors in Bonded Specimens
An investigation into the influence of cracks in bonded specimens is conducted. Photoelastic specimens containing a bondline are subjected to a constant displacement boundary condition created by bonded end grips. Specimens containing various crack orientations are analyzed to determine stress inten...
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| Format: | Others |
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Virginia Tech
2014
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| Online Access: | http://hdl.handle.net/10919/32786 http://scholar.lib.vt.edu/theses/available/etd-05152000-13410027/ |
| Summary: | An investigation into the influence of cracks in bonded specimens is conducted.
Photoelastic specimens containing a bondline are subjected to a constant displacement
boundary condition created by bonded end grips. Specimens containing various crack
orientations are analyzed to determine stress intensity factors at the induced crack tips.
Specimens containing interface and sub-interface cracks were investigated. Two global
geometries were used in this investigation, square and rectangular. The constant
displacement boundary condition was induced on the specimen through dead weights
hung from bonded aluminum end grips. Stress intensity factors were determined using
photoelastic techniques. The stress intensity factors were examined to determine trends
in the results as a function of changes in geometry. The effects of the induced boundary
condition, the specimen geometry, and the bondline were investigated. The results from
this investigation were compared to known solutions with a similar specimen geometry.
These tests exhibited influences from the bondline, the boundary conditions, and the
specimen geometry. The bondline tended to decrease the stress intensity factor for
specimens with small crack lengths and tended to increase the stress intensity factor for
specimens containing long crack lengths. As the crack length increased so too did the
stress intensity factor. A reduction in the bondline to crack distance with sub-interface
crack specimens caused a reduction in the stress intensity factor. A reduction in the
global height of the specimen caused a reduction in the stress intensity factor also. The
results from this investigation will aid in the understanding of the influence of interface
and sub-interface cracks in bonded specimens. === Master of Science |
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