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Failure of Curved Brittle Layer Systems from Radial Cracking in Concentrated Surface Loading



Mattheq Rudas, T Qasim, M T. Bush, Brian R. Lawn


A study is made of radial crack evolution in curved brittle layers on compliant support substrates. Three-dimensional boundary element analysis (BEA) is used to compute the stepwise growth of radial cracks that initiate at the bottom surfaces of glass on polymeric support layers, from initiation to final failure. The algorithm calculates reconstituted displacement fields in the near-tip region of the extending cracks, enabling direct evaluation of stress-intensity factors. Available experimental data on the same material systems with prescribed surface curvatures are used to validate the essential features of the predicted crack evolution, particularly the stability conditions prior to ultimate failure. It is shown that the critical loads to failure diminish with increasing surface curvature. Generalization of the ensuing fracture mechanics to include alternative brittle-layer/polymer-substrate systems enables an explicit expression for the critical load to failure in terms of material properties and layer thicknesses. Implications concerning practical layer systems, particularly dental crowns, are briefly discussed.
Journal of Materials Research


dental crowns, failure analysis, layer structures, radial cracks


Rudas, M. , Qasim, T. , Bush, M. and Lawn, B. (2005), Failure of Curved Brittle Layer Systems from Radial Cracking in Concentrated Surface Loading, Journal of Materials Research, [online], (Accessed May 25, 2024)


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Created September 12, 2005, Updated October 12, 2021