Divergence Instability and Diffuse Failure in Granular Media

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• 作者：Ali Daouadji^a ; Mohamad Jrad^a ; Florent Prunier^b ; Luc Sibille^c ; Franç ; ois Nicot^d ; Farid Laouafa^e ; Fé ; lix Darve^f
• 关键词：instability ; bifurcation ; failure ; kinetic energy ; second order work ; non associativeness
• 刊名：Procedia IUTAM
• 出版年：2012
• 期刊代码：pc140_22109838
• 类别：et
• 出版时间：2012
• 卷：3
• 期：Complete
• 页码：115-140
• 文件大小：1359 K

摘要

The question of divergence instability and diffuse failure, which is a common failure mode for granular materials like soils, is tackled here from an experimental, theoretical and numerical perspective. The necessary condition of instability as given by the loss of definite-positiveness of the elasto-plastic matrix (the so-called 鈥渟econd order work criterion鈥? is considered to analyze some experimental tests leading to diffuse failure, the link between kinetic energy and second order work is established, a discrete element method is used to simulate these failure conditions and eventually a 3D bifurcation analysis is performed with incrementally piecewise and non-linear elasto-plastic relationships. Essentially in relation with the non-associate character of the plastic strains of granular materials, a whole bifurcation domain in the stress space emerges from these analyses, leading to novel views of failure for non-associative materials.