In order to evaluate the capacity of reinforced concrete (RC) structures subjected to blast loadings,the damaged plasticity model for concrete was used in the analysis of the dynamic responses of blast-loaded RC struc...In order to evaluate the capacity of reinforced concrete (RC) structures subjected to blast loadings,the damaged plasticity model for concrete was used in the analysis of the dynamic responses of blast-loaded RC structures,and all three failure modes were numerically simulated by the finite element software ABAQUS.Simulation results agree with the experimental observations.It is demonstrated that the damaged plasticity model for concrete in the finite element software ABAQUS can predict dynamic responses and typical flexure,flexure-shear and direct shear failure modes of the blast-loaded RC structures.展开更多
In order to understand the effect of hardening ductility parameters and softening ductility parameters of the concrete damage plastic model in LS-DYNA,a sensitivity and reliability analysis of these parameters through...In order to understand the effect of hardening ductility parameters and softening ductility parameters of the concrete damage plastic model in LS-DYNA,a sensitivity and reliability analysis of these parameters through a convenient cube unit test was conducted. The results showed that the peak strength strain was independent of the hardening ductility parameter DH,but affected by AH,BH,and CH. The softening ductility was mainly related to the softening ductility parameter AS,but not affected by the damage ductility exponent BS. In case that the model with default parameters failed to match the AS-controlled damage softening phase,an optimized model with an AS correction was developed. The corrected model with the AS value of 2 matched well with the code model,and exhibited good feasibility in predicting the stress-strain curve of different grades of concrete. Moreover,the practicability of the corrected model was further validated by the conventional triaxial test. The simulated curve exhibited favorable consistence with the trial curve. Therefore,the model with parameter correction could provide a prospective reference for predicting the mechanical properties of concrete.展开更多
为了将新型泡沫混凝土动态弹塑性损伤模型应用到防护结构中,首先开展组合式防护结构预制孔装药爆炸试验;随后利用新泡沫混凝土材料模型对试验进行数值模拟验证,并将新模型的模拟结果与LS-DYNA中Soil and Foam模型的模拟结果进行对比;最...为了将新型泡沫混凝土动态弹塑性损伤模型应用到防护结构中,首先开展组合式防护结构预制孔装药爆炸试验;随后利用新泡沫混凝土材料模型对试验进行数值模拟验证,并将新模型的模拟结果与LS-DYNA中Soil and Foam模型的模拟结果进行对比;最后,基于验证的数值模型,开展以梯度泡沫混凝土作为分配层的组合式防护结构预制孔装药爆炸的数值模拟,探讨梯度泡沫混凝土层界面层数和排列方式对组合式防护结构抗爆性能的影响。结果表明,新泡沫混凝土材料模型的模拟结果与试验结果吻合良好,与Soil and Foam模型相比,新模型在应力波传播和损伤破坏方面预测更好,泡沫混凝土层界面层数和排列方式对作用在主体结构上的应力以及分配层的损伤破坏情况有一定的影响。展开更多
The seismic stability of a cracked dam was examined in this study. Geometric nonlinearity and large deformations, as well as the contact condition at the crack site, were taken into consideration. The location of pene...The seismic stability of a cracked dam was examined in this study. Geometric nonlinearity and large deformations, as well as the contact condition at the crack site, were taken into consideration. The location of penetrated cracks was first identified using the concrete plastic-damage model based on the nonlinear finite element method （FEM）. Then, the hard contact algorithm was used to simulate the crack interaction in the normal direction, and the Coloumb friction model was used to simulate the crack interaction in the tangential direction. After verification of numerical models through a case study, the seismic stability of the Koyna Dam with two types of penetrated cracks is discussed in detail with different seismic peak accelerations, and the collapse processes of the cracked dam are also presented. The results show that the stability of the dam with two types of penetrated cracks can be ensured in an earthquake with a magnitude of the original Koyna earthquake, and the cracked dam has a large earthquake-resistant margin. The failure processes of the cracked dam in strong earthquakes can be divided into two stages： the sliding stage and the overturning stage. The sliding stage ends near the peak acceleration, and the top block slides a long distance along the crack before the collapse occurs. The maximum sliding displacement of the top block will decrease with an increasing friction coefficient at the crack site.展开更多
基金Supported by National Natural Science Foundation of China (No.50638030 and 50525825)National Science and Technology Support Program (No.2006BAJ13B02).
文摘In order to evaluate the capacity of reinforced concrete (RC) structures subjected to blast loadings,the damaged plasticity model for concrete was used in the analysis of the dynamic responses of blast-loaded RC structures,and all three failure modes were numerically simulated by the finite element software ABAQUS.Simulation results agree with the experimental observations.It is demonstrated that the damaged plasticity model for concrete in the finite element software ABAQUS can predict dynamic responses and typical flexure,flexure-shear and direct shear failure modes of the blast-loaded RC structures.
基金Supported by the National Natural Science Foundation of China(10272109)
文摘In order to understand the effect of hardening ductility parameters and softening ductility parameters of the concrete damage plastic model in LS-DYNA,a sensitivity and reliability analysis of these parameters through a convenient cube unit test was conducted. The results showed that the peak strength strain was independent of the hardening ductility parameter DH,but affected by AH,BH,and CH. The softening ductility was mainly related to the softening ductility parameter AS,but not affected by the damage ductility exponent BS. In case that the model with default parameters failed to match the AS-controlled damage softening phase,an optimized model with an AS correction was developed. The corrected model with the AS value of 2 matched well with the code model,and exhibited good feasibility in predicting the stress-strain curve of different grades of concrete. Moreover,the practicability of the corrected model was further validated by the conventional triaxial test. The simulated curve exhibited favorable consistence with the trial curve. Therefore,the model with parameter correction could provide a prospective reference for predicting the mechanical properties of concrete.
文摘为了将新型泡沫混凝土动态弹塑性损伤模型应用到防护结构中,首先开展组合式防护结构预制孔装药爆炸试验;随后利用新泡沫混凝土材料模型对试验进行数值模拟验证,并将新模型的模拟结果与LS-DYNA中Soil and Foam模型的模拟结果进行对比;最后,基于验证的数值模型,开展以梯度泡沫混凝土作为分配层的组合式防护结构预制孔装药爆炸的数值模拟,探讨梯度泡沫混凝土层界面层数和排列方式对组合式防护结构抗爆性能的影响。结果表明,新泡沫混凝土材料模型的模拟结果与试验结果吻合良好,与Soil and Foam模型相比,新模型在应力波传播和损伤破坏方面预测更好,泡沫混凝土层界面层数和排列方式对作用在主体结构上的应力以及分配层的损伤破坏情况有一定的影响。
基金supported by the National Basic Research Program of China (973 Program, Grant No. 2007CB714104)the National Natural Science Foundation of China (Grant No. 50779011)the Innovative Project for Graduate Students of Jiangsu Province (Grant No. CX10B_202Z)
文摘The seismic stability of a cracked dam was examined in this study. Geometric nonlinearity and large deformations, as well as the contact condition at the crack site, were taken into consideration. The location of penetrated cracks was first identified using the concrete plastic-damage model based on the nonlinear finite element method （FEM）. Then, the hard contact algorithm was used to simulate the crack interaction in the normal direction, and the Coloumb friction model was used to simulate the crack interaction in the tangential direction. After verification of numerical models through a case study, the seismic stability of the Koyna Dam with two types of penetrated cracks is discussed in detail with different seismic peak accelerations, and the collapse processes of the cracked dam are also presented. The results show that the stability of the dam with two types of penetrated cracks can be ensured in an earthquake with a magnitude of the original Koyna earthquake, and the cracked dam has a large earthquake-resistant margin. The failure processes of the cracked dam in strong earthquakes can be divided into two stages： the sliding stage and the overturning stage. The sliding stage ends near the peak acceleration, and the top block slides a long distance along the crack before the collapse occurs. The maximum sliding displacement of the top block will decrease with an increasing friction coefficient at the crack site.
