Experimental and numerical analysis of size effects on stress intensity in anisotropic porous materials

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Abstract

A prominent size effect has previously been reported for the fracture behaviour of brittle porous materials, with smaller specimens behaving quite differently to their larger counterparts. In such materials, the size of the K-dominant zone has been numerically found to be greatly affected by the presence of voids in the near-tip area, thus putting the assumption of a single fracture parameter under question. In order to address this, in this study mode I tests are conducted on porous double cantilever beam specimens, while the stress distribution in the near-tip area is being observed by means of photoelasticity. Results validate the predicted size eect and suggest that the voids can indeed alter the size and shape of the stress pattern in the specimens. A parametric study is then conducted to investigate the in uence of void shape variations that can be caused by manufacturing inaccuracies on the stress concentration at the crack tip. It is found that although the stress intensity at the crack tip can be greatly aected by such factors, the size of the K-dominant zone remains unaffected.
LanguageEnglish
Number of pages26
JournalEngineering Failure Analysis
Publication statusAccepted/In press - 8 Apr 2019

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Crack tips
Porous materials
Stress concentration
Numerical analysis
Photoelasticity
Cantilever beams

Keywords

  • fracture mechanics
  • size effect
  • porous materials
  • experimental analysis
  • cell shape
  • non-singular stresses

Cite this

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title = "Experimental and numerical analysis of size effects on stress intensity in anisotropic porous materials",
abstract = "A prominent size effect has previously been reported for the fracture behaviour of brittle porous materials, with smaller specimens behaving quite differently to their larger counterparts. In such materials, the size of the K-dominant zone has been numerically found to be greatly affected by the presence of voids in the near-tip area, thus putting the assumption of a single fracture parameter under question. In order to address this, in this study mode I tests are conducted on porous double cantilever beam specimens, while the stress distribution in the near-tip area is being observed by means of photoelasticity. Results validate the predicted size eect and suggest that the voids can indeed alter the size and shape of the stress pattern in the specimens. A parametric study is then conducted to investigate the in uence of void shape variations that can be caused by manufacturing inaccuracies on the stress concentration at the crack tip. It is found that although the stress intensity at the crack tip can be greatly aected by such factors, the size of the K-dominant zone remains unaffected.",
keywords = "fracture mechanics, size effect, porous materials, experimental analysis, cell shape, non-singular stresses",
author = "Dimitra Touliatou and Wheel, {Marcus A.}",
year = "2019",
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language = "English",
journal = "Engineering Failure Analysis",
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T1 - Experimental and numerical analysis of size effects on stress intensity in anisotropic porous materials

AU - Touliatou, Dimitra

AU - Wheel, Marcus A.

PY - 2019/4/8

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N2 - A prominent size effect has previously been reported for the fracture behaviour of brittle porous materials, with smaller specimens behaving quite differently to their larger counterparts. In such materials, the size of the K-dominant zone has been numerically found to be greatly affected by the presence of voids in the near-tip area, thus putting the assumption of a single fracture parameter under question. In order to address this, in this study mode I tests are conducted on porous double cantilever beam specimens, while the stress distribution in the near-tip area is being observed by means of photoelasticity. Results validate the predicted size eect and suggest that the voids can indeed alter the size and shape of the stress pattern in the specimens. A parametric study is then conducted to investigate the in uence of void shape variations that can be caused by manufacturing inaccuracies on the stress concentration at the crack tip. It is found that although the stress intensity at the crack tip can be greatly aected by such factors, the size of the K-dominant zone remains unaffected.

AB - A prominent size effect has previously been reported for the fracture behaviour of brittle porous materials, with smaller specimens behaving quite differently to their larger counterparts. In such materials, the size of the K-dominant zone has been numerically found to be greatly affected by the presence of voids in the near-tip area, thus putting the assumption of a single fracture parameter under question. In order to address this, in this study mode I tests are conducted on porous double cantilever beam specimens, while the stress distribution in the near-tip area is being observed by means of photoelasticity. Results validate the predicted size eect and suggest that the voids can indeed alter the size and shape of the stress pattern in the specimens. A parametric study is then conducted to investigate the in uence of void shape variations that can be caused by manufacturing inaccuracies on the stress concentration at the crack tip. It is found that although the stress intensity at the crack tip can be greatly aected by such factors, the size of the K-dominant zone remains unaffected.

KW - fracture mechanics

KW - size effect

KW - porous materials

KW - experimental analysis

KW - cell shape

KW - non-singular stresses

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