The virtual displacement principle of elasto-plastic damage mechanics is presented. A linear complementary method for elasto-plastic damage problem is proposed by using FEM technique. This method is applicable to solv...The virtual displacement principle of elasto-plastic damage mechanics is presented. A linear complementary method for elasto-plastic damage problem is proposed by using FEM technique. This method is applicable to solving the damage structure analysis of hardened and softened nonlinear material.展开更多
The deformation and damage behaviors of strain hardening cementitious composites （SHCC） under the uniaxial stress state were investigated in this paper. Two ductile failure-based constitutive models were introduced ...The deformation and damage behaviors of strain hardening cementitious composites （SHCC） under the uniaxial stress state were investigated in this paper. Two ductile failure-based constitutive models were introduced to describe the uniaxial tension and compression properties of SHCC only using a few parameters. The computation method of model parameters was developed to ease the simulation procedures. Damage evolution of the SHCC was simulated by the formulation of continuum damage mechanics subsequently. The results show that the proposed models fit the stress-strain curves reasonably well, and the damage variables show different growth rules under uniaxial tension and compression. It is concluded that the proposed method can not only simply simulate the constitutive behavior of SHCC with the reasonable accuracy but also capture the characteristic of material degradation.展开更多
This investigation discusses further the extent to which a new damage theory recently proposed by the author can serve as a unified theory to characteriz;e various ductile failure problems. A general damage integral a...This investigation discusses further the extent to which a new damage theory recently proposed by the author can serve as a unified theory to characteriz;e various ductile failure problems. A general damage integral and corresponding criterion for ductile fracture are presented. A new parameter for ductile fracture is emphasized, which is experimentally verified as a material constant independent of stress state, has clear physical meaning, and can easily be determined. The applicability of this theory to evaluation of the ductility Of welds and engineering materials under various conditions is examined. Also, it is used to predict the effect of residual stress on failure of welds, to predict sheetforming limits, and to correlate the variability of elasto-plastic fracture toughness values J(1c) and delta(c) with different specimen geometries. A new constraint correction method is proposed, and constraint corrected new toughness parameters J(dc) and delta(dc) are recommended. Experiments have shown that the toughness variation with different specimen geometries can effectively be removed by use of the method. The general applicability of the theory to characterization of various ductile failures provides a new design tool for engineering components or structures.展开更多
采用锦屏二级水电站埋深2000m的白山组大理岩试样进行单轴压缩-声发射试验,通过试验结果的分析确定白山组大理岩的启裂强度和损伤强度,分别为0.4～0.5倍和0.8倍的单轴抗压强度,试验结果与加拿大URL针对Lac du Bonnet花岗岩的测试成果相...采用锦屏二级水电站埋深2000m的白山组大理岩试样进行单轴压缩-声发射试验,通过试验结果的分析确定白山组大理岩的启裂强度和损伤强度,分别为0.4～0.5倍和0.8倍的单轴抗压强度,试验结果与加拿大URL针对Lac du Bonnet花岗岩的测试成果相接近。针对白山组深埋大理岩开展室内三轴压缩试验,试验成果显示锦屏白山组大理岩随着围压的增大其峰后应力-应变曲线具有明显的脆-延-塑转换特征。对比锦屏白山组大理岩、Lac du Bonnet花岗岩以及三峡花岗岩的三轴试验成果,说明大理岩和花岗岩峰后力学特征的显著差异。采用Hoek-Brown强度准则的本构模型描述大理岩的脆-延-塑转换特征,并将研究成果应用于引水隧洞的围岩损伤深度预测。展开更多
文摘The virtual displacement principle of elasto-plastic damage mechanics is presented. A linear complementary method for elasto-plastic damage problem is proposed by using FEM technique. This method is applicable to solving the damage structure analysis of hardened and softened nonlinear material.
基金This research is funded by the National Key Technology R&D Program of China (No. 2011BAE27B04)the Special Fund for Basic Scientific Research of Central Colleges in Chang’an University (Nos. CHD2011TD003 and CHD2011ZY002)
文摘The deformation and damage behaviors of strain hardening cementitious composites （SHCC） under the uniaxial stress state were investigated in this paper. Two ductile failure-based constitutive models were introduced to describe the uniaxial tension and compression properties of SHCC only using a few parameters. The computation method of model parameters was developed to ease the simulation procedures. Damage evolution of the SHCC was simulated by the formulation of continuum damage mechanics subsequently. The results show that the proposed models fit the stress-strain curves reasonably well, and the damage variables show different growth rules under uniaxial tension and compression. It is concluded that the proposed method can not only simply simulate the constitutive behavior of SHCC with the reasonable accuracy but also capture the characteristic of material degradation.
文摘This investigation discusses further the extent to which a new damage theory recently proposed by the author can serve as a unified theory to characteriz;e various ductile failure problems. A general damage integral and corresponding criterion for ductile fracture are presented. A new parameter for ductile fracture is emphasized, which is experimentally verified as a material constant independent of stress state, has clear physical meaning, and can easily be determined. The applicability of this theory to evaluation of the ductility Of welds and engineering materials under various conditions is examined. Also, it is used to predict the effect of residual stress on failure of welds, to predict sheetforming limits, and to correlate the variability of elasto-plastic fracture toughness values J(1c) and delta(c) with different specimen geometries. A new constraint correction method is proposed, and constraint corrected new toughness parameters J(dc) and delta(dc) are recommended. Experiments have shown that the toughness variation with different specimen geometries can effectively be removed by use of the method. The general applicability of the theory to characterization of various ductile failures provides a new design tool for engineering components or structures.
文摘采用锦屏二级水电站埋深2000m的白山组大理岩试样进行单轴压缩-声发射试验,通过试验结果的分析确定白山组大理岩的启裂强度和损伤强度,分别为0.4～0.5倍和0.8倍的单轴抗压强度,试验结果与加拿大URL针对Lac du Bonnet花岗岩的测试成果相接近。针对白山组深埋大理岩开展室内三轴压缩试验,试验成果显示锦屏白山组大理岩随着围压的增大其峰后应力-应变曲线具有明显的脆-延-塑转换特征。对比锦屏白山组大理岩、Lac du Bonnet花岗岩以及三峡花岗岩的三轴试验成果,说明大理岩和花岗岩峰后力学特征的显著差异。采用Hoek-Brown强度准则的本构模型描述大理岩的脆-延-塑转换特征,并将研究成果应用于引水隧洞的围岩损伤深度预测。
