Localized rock failures,like cracks or shear bands,demand specific attention in modeling for solids and structures.This is due to the uncertainty of conventional continuum-based mechanical models when localized inelas...Localized rock failures,like cracks or shear bands,demand specific attention in modeling for solids and structures.This is due to the uncertainty of conventional continuum-based mechanical models when localized inelastic deformation has emerged.In such scenarios,as macroscopic inelastic reactions are primarily influenced by deformation and microstructural alterations within the localized area,internal variables that signify these microstructural changes should be established within this zone.Thus,localized deformation characteristics of rocks are studied here by the preset angle shear experiment.A method based on shear displacement and shear stress differences is proposed to identify the compaction,yielding,and residual points for enhancing the model's effectiveness and minimizing subjective influences.Next,a mechanical model for the localized shear band is depicted as an elasto-plastic model outlining the stress-displacement relation across both sides of the shear band.Incorporating damage theory and an elasto-plastic model,a proposed damage model is introduced to replicate shear stressdisplacement responses and localized damage evolution in intact rocks experiencing shear failure.Subsequently,a novel nonlinear mathematical model based on modified logistic growth theory is proposed for depicting the shear band's damage evolution pattern.Thereafter,an innovative damage model is proposed to effectively encompass diverse rock material behaviors,including elasticity,plasticity,and softening behaviors.Ultimately,the effects of the preset angles,temperature,normal stresses and the residual shear strength are carefully discussed.This discovery enhances rock research in the proposed damage model,particularly regarding shear failure mode.展开更多
A novel shear damage model based on homogenization theory and a modified Mohr-Coulomb criterion is proposed to predict the full deformation process of gas hydrate-bearing sediments(GHBSs)during shearing by analyzing m...A novel shear damage model based on homogenization theory and a modified Mohr-Coulomb criterion is proposed to predict the full deformation process of gas hydrate-bearing sediments(GHBSs)during shearing by analyzing micro-mechanisms of shear deformation and failure characteristics.Then,the physical significance of the model's parameters is explored.Finally,the damage evolution and shear stress partition inside GHBSs during the shearing process are analyzed in detail.The results show that model parameters have clear physical meaning,and the shear damage model is capable of reflecting the nonlinear deformation and strain softening characteristics of GHBSs due to its ability to better describe the damage evolution and shear stress partition mechanisms inside GHBSs during the shearing process.Comparisons of experimental and theoretical results show that the global performance of the novel shear damage model is satisfactory.The model is expected to be widely adopted to analyze submarine landslide instability due to hydrate dissociation.展开更多
将修正的Burgers模型看成是Van Der Pool模型与一个非线性黏壶串联而成,认为材料损伤演化过程只是导致模型中串联黏壶的黏度降低,其他3个元件并没有受到损伤;用Weibull函数来描述沥青混合料内部缺陷的分布,从统计学的角度出发建立了损...将修正的Burgers模型看成是Van Der Pool模型与一个非线性黏壶串联而成,认为材料损伤演化过程只是导致模型中串联黏壶的黏度降低,其他3个元件并没有受到损伤;用Weibull函数来描述沥青混合料内部缺陷的分布,从统计学的角度出发建立了损伤演化方程,将损伤引入修正的Burgers模型的非线性黏壶,建立了沥青混合料的黏弹性损伤模型;给出了蠕变应变、蠕变速度和蠕变加速度的解析表达式,证明了该模型能很好地反映沥青混合料三阶段的蠕变特性;最后通过两个试验算例验证了模型的准确性和适用性。研究结果表明,只考虑串联黏壶的损伤不仅较以往的蠕变损伤模型更加简单,而且能很好地反映实验结果,最重要的是这种处理有了更合理的理论根据。展开更多
基金supported by the China Scholarship Council Program(Grant No.202008320274)it is also supported by Technical University of Munich.
文摘Localized rock failures,like cracks or shear bands,demand specific attention in modeling for solids and structures.This is due to the uncertainty of conventional continuum-based mechanical models when localized inelastic deformation has emerged.In such scenarios,as macroscopic inelastic reactions are primarily influenced by deformation and microstructural alterations within the localized area,internal variables that signify these microstructural changes should be established within this zone.Thus,localized deformation characteristics of rocks are studied here by the preset angle shear experiment.A method based on shear displacement and shear stress differences is proposed to identify the compaction,yielding,and residual points for enhancing the model's effectiveness and minimizing subjective influences.Next,a mechanical model for the localized shear band is depicted as an elasto-plastic model outlining the stress-displacement relation across both sides of the shear band.Incorporating damage theory and an elasto-plastic model,a proposed damage model is introduced to replicate shear stressdisplacement responses and localized damage evolution in intact rocks experiencing shear failure.Subsequently,a novel nonlinear mathematical model based on modified logistic growth theory is proposed for depicting the shear band's damage evolution pattern.Thereafter,an innovative damage model is proposed to effectively encompass diverse rock material behaviors,including elasticity,plasticity,and softening behaviors.Ultimately,the effects of the preset angles,temperature,normal stresses and the residual shear strength are carefully discussed.This discovery enhances rock research in the proposed damage model,particularly regarding shear failure mode.
基金supported by the Independent Innovation Research Program of China University of Petroleum(East China)(No.27RA2215005)。
文摘A novel shear damage model based on homogenization theory and a modified Mohr-Coulomb criterion is proposed to predict the full deformation process of gas hydrate-bearing sediments(GHBSs)during shearing by analyzing micro-mechanisms of shear deformation and failure characteristics.Then,the physical significance of the model's parameters is explored.Finally,the damage evolution and shear stress partition inside GHBSs during the shearing process are analyzed in detail.The results show that model parameters have clear physical meaning,and the shear damage model is capable of reflecting the nonlinear deformation and strain softening characteristics of GHBSs due to its ability to better describe the damage evolution and shear stress partition mechanisms inside GHBSs during the shearing process.Comparisons of experimental and theoretical results show that the global performance of the novel shear damage model is satisfactory.The model is expected to be widely adopted to analyze submarine landslide instability due to hydrate dissociation.
文摘将修正的Burgers模型看成是Van Der Pool模型与一个非线性黏壶串联而成,认为材料损伤演化过程只是导致模型中串联黏壶的黏度降低,其他3个元件并没有受到损伤;用Weibull函数来描述沥青混合料内部缺陷的分布,从统计学的角度出发建立了损伤演化方程,将损伤引入修正的Burgers模型的非线性黏壶,建立了沥青混合料的黏弹性损伤模型;给出了蠕变应变、蠕变速度和蠕变加速度的解析表达式,证明了该模型能很好地反映沥青混合料三阶段的蠕变特性;最后通过两个试验算例验证了模型的准确性和适用性。研究结果表明,只考虑串联黏壶的损伤不仅较以往的蠕变损伤模型更加简单,而且能很好地反映实验结果,最重要的是这种处理有了更合理的理论根据。
