Behavior of indentation cracks near free surfaces and interfaces

Lardner, T. J.; Ritter, J. E.; Shiao, M. L.; Lin, Meng

doi:10.1007/bf00047064

Cited by 55 publications

(34 citation statements)

References 15 publications

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“…However, the magnitude of increase was less than that for the crack running perpendicular to the interface. The crack running near parallel to the interface deflects under the influence of the elastic mismatch, as previously described 13) . Based on these considerations, the transverse radial cracks were most suitable for this investigation.…”

Section: Discussionmentioning

confidence: 98%

“…The degree of crack slanting was greater for smaller marginal angles and shorter distances from the ceramic/resin interface. Several studies have reported on crack slanting or deflection in ceramic materials with a marginal angle of 90° 13,14,[22][23][24] . Crack slanting or deflection occurred with marginal angles of 45 and 60°.…”

Section: Discussionmentioning

confidence: 99%

“…Lengthening and slanting of indentation cracks are related to changes in the mode I and II stress intensity factors (KI, KII), respectively. Cracks near the edge of a material propagate with an increase in complex stress intensity factors (combination of KI and KII) at the crack tip 13,19,25) . KI and KII for cracks near an edge may be obtained using the following equations by Lardner et al…”

Section: Discussionmentioning

confidence: 99%

“…Yamamoto and Nishiura 14) measured the lengths of radial cracks running along the ceramic/ resin composite interface and found that the lengths of the cracks increased as the indentation approached the interface more closely. In these two studies, the angle of the ceramic margins was 90° 13,14) . However, in clinical settings, the marginal angles of ceramic restorations at the occlusal surface are often less than 90°, due to the anatomic form of the tooth.…”

Section: Introductionmentioning

confidence: 98%

“…Lardner et al 13) revealed that radial cracks in glass emanating from the corners of a Knoop indentation were lengthened and curved when the indent was introduced near the glass/epoxy interface. The increased length was attributed to an increase in the stress intensity factor.…”

Section: Introductionmentioning

confidence: 99%

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Cracks formed by Vickers indentation adjacent to the interface in bonded dental ceramics with various marginal angles

et al. 2011

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The objective of this study was to assess the influence of the ceramic marginal angle on the length and nature of indentation cracks in ceramics near the ceramic/resin bonded interface. Disks of a leucite-reinforced ceramic or a diopside-based glass-ceramic bonded to a resin composite were sectioned so that the ceramic marginal angles were 45, 60, and 90°. Vickers indentations were placed in the ceramic at various distances from the bonded interface. The lengths of the indentation cracks running near parallel to the interface were measured and the orientation of crack propagation was characterized. The crack length and orientation were significantly affected by the distance from the interface and by the marginal angle, respectively. The crack length extended as the distance from the interface was shortened. Smaller marginal angles resulted in more oblique cracks. The toughness of the ceramic affected the indentation crack length, shape, and direction.

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Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Cracks formed by Vickers indentation adjacent to the interface in bonded dental ceramics with various marginal angles

et al. 2011

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Transverse fracture of brittle bilayers: Relevance to failure of all‐ceramic dental crowns

et al. 2006

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This study examines the behavior of cracks approaching interfaces in all-ceramic dental crown-like bilayers. Flat specimens are fabricated by fusing porcelain veneers onto yttria-tetragonal-zirconia-polycrystal (Y-TZP) and alumina core ceramic plates, with veneer/core matching to minimize residual thermal expansion mismatch stresses. Vickers indentations are placed on either side of the interfaces, at systematically decreasing distances, so that the lead corner cracks approach and intersect the interfaces in a normal orientation. Cracks originating in the porcelain arrest at the boundaries and, after further diminution in indentation distance, deflect along the interface without penetration into the tough core ceramic. Cracks initiating in the core ceramic pass unimpeded into the weaker porcelain without deflection, and with abrupt increase in crack size. These latter cracks, because of their lack of containment within the core layer, are regarded as especially dangerous. Implications concerning the design of optimal dental crowns in relation to materials optimization are considered.

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Prediction of interfacial crack path: a direct boundary integral approach and experimental study

1994

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This paper presents the development of a higher-order direct boundary integral-displacement discontinuity method for crack propagation in layered elastic materials. The method is based on the dual boundary integral equations of linear elasticity which are solved by means of a quadratic boundary element formulation. The analytical solution for a point force within a bonded half-plane region is used to derive the kernel functions of the boundary integral equations. Square-root displacement-discontinuity elements are used to model the crack tips, and stress intensity factors may be computed using the numerically predicted values of the displacement discontinuity components at the midpoints of these crack-tip elements. An algorithm based on the maximum tensile-stress criterion is then developed and incorporated into the boundary element model to predict the paths of cracks propagating in layered elastic materials.In the experimental part of this study, crack profiles for straight-through-cracked, compact-tension specimens of the anodically bonded silicon/Pyrex glass system are measured by profilometry. The plane strain prediction of the crack-propagation path is compared with the experimentally measured crack profiles. Consistent with the prediction, the interfacial crack is observed to kink away from the strong, anodicaUy-bonded interface and propagate into the more compliant glass layer. The predicted initial kink angle of 26 ° agrees very well with the average measured value of 280 . The measured path of the crack is also in very good agreement with the predicted path over about the first 120 microns of crack growth with increasing deviation observed beyond that.

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Behavior of indentation cracks near free surfaces and interfaces

Cited by 55 publications

References 15 publications

Cracks formed by Vickers indentation adjacent to the interface in bonded dental ceramics with various marginal angles

Cracks formed by Vickers indentation adjacent to the interface in bonded dental ceramics with various marginal angles

Transverse fracture of brittle bilayers: Relevance to failure of all‐ceramic dental crowns

Prediction of interfacial crack path: a direct boundary integral approach and experimental study

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