Estimation of the crack propagation direction in a mixed-mode geometry via multi-parameter fracture criteria
The presented work introduces a numerical parametric study on the crack propagation direction under mixed-mode conditions (mode I + II). It is conducted for the geometry of an eccentric asymmetric fourpoint bending of a single edge notched beam specimen; various levels of mode-mixity are ensured b...
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| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Gruppo Italiano Frattura
2015-07-01
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| Series: | Fracture and Structural Integrity |
| Subjects: | |
| Online Access: | http://www.gruppofrattura.it/pdf/rivista/numero33/numero_33_art_4.pdf |
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| Summary: | The presented work introduces a numerical parametric study on the crack propagation direction
under mixed-mode conditions (mode I + II). It is conducted for the geometry of an eccentric asymmetric fourpoint
bending of a single edge notched beam specimen; various levels of mode-mixity are ensured by
modifications in the crack length and crack eccentricity. The direction of crack propagation is estimated semianalytically
using both the maximum tangential stress criterion and the strain energy density criterion
(implemented as a procedure within the used finite element computational code) as well as numerically (from
verification reasons). Multi-parameter fracture mechanics is employed in the presented work for precise
analytical evaluation of the stress field in the cracked specimen. This theory is based on description of the stress
and deformation fields in the cracked body by means of their approximation using several initial terms of the
Williams power series. Recent studies show that utilization of only first term of the series, which corresponds to
the stress intensity factor (SIF), the single controlling parameter for the crack initiation and propagation
assessment in brittle materials, is insufficient in many crack problems. It appears also in this study that the
higher-order terms of the asymptotic crack-tip field are of great relevance for the conducted analysis, similarly
to a number of other fracture phenomena (near-crack-tip stress field approximation, non-linear zone extent
estimation, etc.). |
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| ISSN: | 1971-8993 1971-8993 |