Finite element analysis of elastic-plastic large deformation crack tip fields
- Metallurgical and Engineering Consultant, Los Angeles, CA (United States)
- Univ. of California, Los Angeles, CA (United States)
Traditional fracture mechanics techniques are founded upon analytical characterization of crack tip fields based on classical small strain solid mechanics concepts. Such characterizations, for both elastic materials and models of metal plasticity, invariably lead to predictions of unbounded strain fields in the vicinity of a sharp crack tip in a loaded body, violating the small strain kinematic assumptions. Nonetheless, these approaches are valuable in predicting fracture behavior for a wide range of structural materials. The utility of small strain results relies on arguments that under limited conditions the extent of crack tip regions which are dominated by finite deformation effects is small relative to the singular zone size. Experiment and analysis allows identification of situations, such as small scale yielding, where the small strain predictions can then be employed in assessing fracture behavior. However, evaluation of fracture in tough metals, which exhibit extensive crack tip blunting, taxes the capabilities of traditional techniques. Finite element analysis (FEA) can be used for finite deformation fracture mechanics modeling. Examples of FEA applied to such problems include: deep blunt notches in plane strain elastic-plastic bending and center-cracked specimens, a sharp, crack in a plane strain hyperelastic center-cracked specimen, and growth of a sharp crack in plane strain elastic-plastic material loaded under small scale yielding. This paper presents Finite deformation FEA of a center-cracked panel with an initially sharp crack in an elastic- plastic material under plane stress. Results demonstrate the ability of the mesh to resolve small strain linear elastic, small strain plastic, and finite deformation crack tip zones. Non-proportional loading due to blunting of the stationary crack tip is displayed. Effects of Finite deformation on energy release rate and the J-integral are discussed.
- OSTI ID:
- 175366
- Report Number(s):
- CONF-950686--
- Country of Publication:
- United States
- Language:
- English
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