Self-driven tunneling crack arrays—a 3D-fracture mechanics bifurcation analysis

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• 作者：M. Hofmann ; H. A. Bahr ; T. Linse ; U. Bahr ; H. Balke and H. J. Weiss
• 关键词：Fracture mechanics ; Crack pattern selection ; Bifurcation analysis
• 刊名：International Journal of Fracture
• 出版年：2006
• 出版时间：October, 2006
• 年：2006
• 卷：141
• 期：3-4
• 页码：345-356
• 全文大小：363 KB
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Chemistry
  Characterization and Evaluation Materials
  Mechanics
  Civil Engineering
  Automotive and Aerospace Engineering and Traffic
  Mechanical Engineering
  
• 出版者：Springer Netherlands
• ISSN：1573-2673

文摘

Tunneling cracks driven by drying in a ceramic precursor confined between two glass plates represent a simple type of three-dimensional (3D) crack pattern. They arrange themselves via mutual unloading which causes some cracks to stop whereby the remaining ones get the right spacing for further propagation. By extending a 2D-model of self-driven propagation of crack arrays, a fracture mechanical bifurcation analysis for 3D-crack patterns based on calculating the post-critical contour of the alternating bifurcation mode has been developed. Shrinkage due to drying is replaced here by a simplified thermo-mechanical model based on an effective heat flow whose related temperature field and thermal stresses drive crack propagation. By means of the finite element method, the propagation velocity and the minimum spacing between the steady-state parallel tunnelling cracks are determined. Comparison of theory and experiment suggests that propagation may be non-stationary in these experiments. The observed relation between crack spacing and layer thickness, p ~ e 2/3, follows from a scaling analysis.