Crack Kinking Criterion for Bimaterial System

Author(s):  
Jianliang Yao ◽  
Toshihisa Nishioka ◽  
Takuma Nozaki ◽  
Takehiro Fujimoto

This paper is aimed to find out a suitable criterion for predicting the interfacial crack in the bimaterial system. An investigation was undertaken into the interfacial crack kinking phenomena in a bimaterial specimen of epoxy and aluminum alloy using a combination of experimental method and numerical simulation. It was found that all kinked fractures occurred at loading angles equal to or larger than 120°, so the kinking direction heavily dependeds on the loading mode mixity. Three categories of fracture pattern were identified (A, B and C). In the case of type A fracture, the (J10)kink integrals were generally higher than the homogeneous epoxy Jic at loading angles of 120° and above. In contrast, for types B and C fracture, the J10 integrals were consistently lower than the homogeneous epoxy Jic. Predictions of crack kinking behavior made using the Maximum Energy Release Rate Criterion (MG-criterion) were found to agree well with the observed experimental results. The kinked deformation of crack tip observed by moire´ interferometry, is well agreed with the result of numerical simulation.

1978 ◽  
Vol 45 (3) ◽  
pp. 553-558 ◽  
Author(s):  
C.-H. Wu

The title problem is studied for the cases: (1) crack-perpendicular tension and crack-parallel shear, (2) plane biaxial load, (3) crack-parallel shear and antiplane shear, and (4) unidirectional load and antiplane shear. All the results are based on a fundamental investigation reported in references [1, 2], the results of which are partly exact, and partly asymptotic and numerical. Neither the maximum-stress nor the minimum-strain-energy-density criterion indicates a coupling between plane and antiplane loads.


2007 ◽  
Vol 336-338 ◽  
pp. 363-366
Author(s):  
Yong Zhang ◽  
Z. Xu

Propagation and deflection of microcracks driven by electric loading in <001>-oriented 0.69Pb(Mg1/3Nb2/3)O3-0.31PbTiO3 ferroelectric single crystals were investigated using an in-situ transmission electron microcopy (TEM) technique. The static observation of the domain pattern revealed the coexistence of sub-micrometer and nano-meter domains. Electric field induced deviation from the main microcrack path and subsequent propagation along the direction almost perpendicular to the electric field were observed directly. A qualitative analyses is given based on the maximum energy release rate criterion.


1994 ◽  
Vol 61 (3) ◽  
pp. 560-566 ◽  
Author(s):  
P. H. Geubelle ◽  
W. G. Knauss

The problem of the growth of a crack located at the interface between two linearly elastic solids is considered when conditions promoting propagation along and/or away from the interface prevail. Both a stress and a maximum energy release rate criterion are examined. It is found that in contrast to the corresponding problem for crack growth in homogeneous solids, no unique propagation direction results when continuum considerations prevail alone. Uniqueness is established only upon invoking a presumably material dictated minimum crack extension size. The result for this linearized analysis are compared with experimental observations on kink fracture involving two elastomers of small strain capabilities.


1998 ◽  
Vol 120 (4) ◽  
pp. 424-430 ◽  
Author(s):  
J. H. Kuang ◽  
C. K. Chen

Crack failure prediction is a prerequisite to assess the safety margin for pressure vessels with interacting parallel cracks. Therefore, an alternating iteration method with approximated image traction is employed in this study to assess the stress intensity factors of two stacked parallel cracks. The predicted crack intensity factors for these parallel cracks correlate well with the recent available solutions in literature. Maximum-energy-release-rate criterion is also utilized for converting problems of multiple cracks into a single crack in mode I. Results demonstrate that a shorter secondary parallel crack may enhance the equivalent crack primarily in the regions 0 < h/2a1 ≤ 0.8 and −1 ≤ t/a1 ≤ 1. The predicted results can be used to evaluate the conformability of simple proximity rules suggested by ASME Boiler & Pressure Vessel Code (ASME B&PV Code).


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