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Experimental investigation of a strain softening approach to predicting failure of notched composite laminates Kongshavn, Ingrid A.
Abstract
This work describes an experimental investigation of a strain softening approach to the prediction of fracture in notched composite laminates. This approach has been found to more accurately predict fracture of large notched coupons or structures than traditional approaches. Strain softening accounts for the effect of damage in front of the notch tip, by the post-peak region of a strain softening curve. This region is traditionally defined by a stress that decreases with increasing strain. A physical understanding of the post-peak region of the curve is required to better examine the predictive capabilities of strain softening. For this to be achieved, a detailed physical understanding of the damage in the process zone is required. In this study, two carbon fibre reinforced laminate material systems were examined. An overheight compact tension (OCT) specimen was developed to grow damage in a stable manner. The displacements in front of the notch tip indicated the progression of damage across the specimen width throughout the test. A detailed physical description of the damage, which consisted of a crack and process zone were obtained. The sequence of damage growth in the process zone was determined. Tensile specimens cut from the process zones indicated a preliminary shape of the strain softening curves for the two material systems. Finally, the experimental results were used to calibrate a preliminary F E M strain softening analysis of the OCT specimens. The preliminary F E M results suggest that a strain softening material response is necessary to capture the progressive damage growth across the specimen width.
Item Metadata
Title |
Experimental investigation of a strain softening approach to predicting failure of notched composite laminates
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
1996
|
Description |
This work describes an experimental investigation of a strain softening approach to the
prediction of fracture in notched composite laminates. This approach has been found to more
accurately predict fracture of large notched coupons or structures than traditional approaches.
Strain softening accounts for the effect of damage in front of the notch tip, by the post-peak
region of a strain softening curve. This region is traditionally defined by a stress that decreases
with increasing strain.
A physical understanding of the post-peak region of the curve is required to better examine the
predictive capabilities of strain softening. For this to be achieved, a detailed physical
understanding of the damage in the process zone is required. In this study, two carbon fibre
reinforced laminate material systems were examined. An overheight compact tension (OCT)
specimen was developed to grow damage in a stable manner. The displacements in front of the
notch tip indicated the progression of damage across the specimen width throughout the test. A
detailed physical description of the damage, which consisted of a crack and process zone were
obtained. The sequence of damage growth in the process zone was determined. Tensile
specimens cut from the process zones indicated a preliminary shape of the strain softening curves
for the two material systems. Finally, the experimental results were used to calibrate a
preliminary F E M strain softening analysis of the OCT specimens. The preliminary F E M results
suggest that a strain softening material response is necessary to capture the progressive damage
growth across the specimen width.
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Extent |
18797273 bytes
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Genre | |
Type | |
File Format |
application/pdf
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Language |
eng
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Date Available |
2009-02-11
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0078483
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
1996-11
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.