Affiliation:
1. Division of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138
Abstract
Ceramic coatings deposited on metal substrates generally develop significant compressive stresses when cooled from the temperature at which they are processed as a result of thermal expansion mismatch. One of the main failure modes for these coatings is edge delamination. For an ideally brittle interface, the edge delamination of a compressed thin film involves mode II interface cracking. The crack faces are in contact with normal stress acting across the faces behind the advancing tip. Frictional shielding of the crack tip has been shown to increase the apparent fracture toughness. Roughness effects associated with the separating faces can also contribute to the apparent toughness. A model of mode II steady-state edge delamination that incorporates combined friction and roughness effects between the delaminated film and substrate is proposed and analyzed. This model is used to assess whether frictional shielding and surface roughness effects are sufficient to explain the large apparent mode II fracture toughness values observed in experiments.
Subject
Mechanical Engineering,Mechanics of Materials,Condensed Matter Physics
Reference7 articles.
1. Yu, H., He, M. Y., and Hutchinson, J. W., 2001, “Edge Effects in Thin Films,” Acta Mater., in print.
2. Hutchinson, J. W., and Suo, Z., 1992, “Mixed Mode Cracking in Layered Materials,” Adv. Appl. Mech., 29, pp. 63–191.
3. Stringfellow, R. G., and Freund, L. B., 1993, “The Effect of Interfacial Friction on the Buckle-Driven Spontaneous Delamination of a Compressed Thin Film,” Int. J. Solids Struct., 30, pp. 1379–1395.
4. Rice, J. R.
, 1968, “Mathematical Analysis in the Mechanics of Fracture,” Fracture, 2, pp. 191–311.
5. Dundurs, J., 1969, “Elastic Interaction of Dislocations With Inhomogeneities,” Mathematical Theory of Dislocations, ASME, New York, pp. 70–115.
Cited by
22 articles.
订阅此论文施引文献
订阅此论文施引文献，注册后可以免费订阅5篇论文的施引文献，订阅后可以查看论文全部施引文献