Failure of curved brittle layer systems from radial cracking in concentrated surface loading
Failure of curved brittle layer systems from radial cracking in concentrated surface loading
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DOI：
10.1557/jmr.2005.0343
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发表时间：
2005-10-01
影响因子：
2.7
通讯作者：
Lawn, BR
中科院分区：
文献类型：
--
作者：
Rudas, M;Qasim, T;Lawn, BR
研究了柔性支承基底上弯曲脆性层中的径向裂纹演化。三维边界元分析用于计算径向裂纹的逐步增长，在聚合物支撑层上的玻璃的底部表面处开始，从开始到最终失效。该算法计算延伸裂纹近尖端区域的重建位移场，从而能够直接评估应力强度因子。相同的材料系统与规定的表面曲率的实验数据被用来验证预测的裂纹演化的基本特征，特别是在最终失效之前的稳定性条件。结果表明，临界失效载荷随表面曲率的增大而减小。随后的断裂力学，包括替代脆性层/聚合物基板系统的推广，使一个明确的表达的临界载荷失效的材料性能和层厚度。有关实际的层系统，特别是牙冠的影响，进行了简要讨论。
A study was made of radial crack evolution in curved brittle layers on compliant support substrates. Three-dimensional boundary element analysis was 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 were used to validate the essential features of the predicted crack evolution, particularly the stability conditions prior to ultimate failure. It was 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 enabled 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.