Cables composed of rare-earth barium copper oxide(REBCO)tapes have been extensively used in various superconducting devices.In recent years,conductor on round core(CORC)cable has drawn the attention of researchers wit...Cables composed of rare-earth barium copper oxide(REBCO)tapes have been extensively used in various superconducting devices.In recent years,conductor on round core(CORC)cable has drawn the attention of researchers with its outstanding current-carrying capacity and mechanical properties.The REBCO tapes are wound spirally on the surface of CORC cable.Under extreme loadings,the REBCO tapes with layered composite structures are vulnerable,which can lead to degradation of critical current and even quenching of superconducting devices.In this paper,we simulate the deformation of CORC cable under external loads,and analyze the damage inside the tape with the cohesive zone model(CZM).Firstly,the fabrication and cabling of CORC are simulated,and the stresses and strains generated in the tape are extracted as the initial condition of the next step.Then,the tension and bending loads are applied to CORC cable,and the damage distribution inside the tape is presented.In addition,the effects of some parameters on the damage are discussed during the bending simulations.展开更多
This paper concentrates on simulating fracture in thin walled single-lap joints connected by resistance spot-welding(RSW)process which were subjected to tensile loading.For this purpose,three sets of lap-joints with d...This paper concentrates on simulating fracture in thin walled single-lap joints connected by resistance spot-welding(RSW)process which were subjected to tensile loading.For this purpose,three sets of lap-joints with different spot configurations were tested to achieve the joints’tensile behavior.To simulate the joints tensile behavior,firstly a 2D axisymmetric finite element(FE)model was used to calculate residual stresses induced during the welding process.Then the results were transferred to 3D models as pre-stress.In this step,cohesive zone model(CZM)technique was used to simulate fracture in the models under tensile load.Cohesive zone parameters were extracted using coach-peel and shear lap specimens.The results were employed to simulate deformation and failure in single lap spot weld samples.It has been shown that considering the residual stresses in simulating deformation and fracture load enables quite accurate predictions.展开更多
Investigation of paper cutting process is vital for the design of cutting tools,but the fracture mechanism of paper cutting is still unclear.Here,we focus on the cutting process of paper,including the key parameters o...Investigation of paper cutting process is vital for the design of cutting tools,but the fracture mechanism of paper cutting is still unclear.Here,we focus on the cutting process of paper,including the key parameters of cohesive zone model(CZM)for the orthotropic paper,to simulate the shear fracture process.Firstly,the material constants of the orthotropic paper are determined by longitudinal and transverse tensile test.Secondly,based on the tensile stressstrain curves,combined with damage theory and numerical simulations,the key parameters of the CZM for the orthotropic paper are obtained.Finally,a model III fracture is simulated to verify the accuracy of the model.Results show that the load-displacement curves obtained by the simulation is consistent with the test results.展开更多
锚杆是岩土工程中重要的支护构件,本文基于CZM(Cohesive Zone Model)模型分析全长粘结式锚杆的脱粘破坏特性。结果表明:对于岩石里固化后的水泥灌浆锚杆脱粘破坏主要经过3个阶段:弹性阶段、塑性破坏阶段、完全破坏阶段。锚固长度在一定...锚杆是岩土工程中重要的支护构件,本文基于CZM(Cohesive Zone Model)模型分析全长粘结式锚杆的脱粘破坏特性。结果表明:对于岩石里固化后的水泥灌浆锚杆脱粘破坏主要经过3个阶段:弹性阶段、塑性破坏阶段、完全破坏阶段。锚固长度在一定范围内变化时,增加锚固长度,并不能增大破坏时的位移。展开更多
Fully automatic finite element(FE) modelling of the fracture process in quasi-brittle materials such as concrete and rocks and ductile materials such as metals and alloys,is of great significance in assessing structur...Fully automatic finite element(FE) modelling of the fracture process in quasi-brittle materials such as concrete and rocks and ductile materials such as metals and alloys,is of great significance in assessing structural integrity and presents tre-mendous challenges to the engineering community. One challenge lies in the adoption of an objective and effective crack propagation criterion. This paper proposes a crack propagation criterion based on the principle of energy conservation and the cohesive zone model(CZM) . The virtual crack extension technique is used to calculate the differential terms in the criterion. A fully-automatic discrete crack modelling methodology,integrating the developed criterion,the CZM to model the crack,a simple remeshing procedure to accommodate crack propagation,the J2 flow theory implemented within the incremental plasticity framework to model the ductile materials,and a local arc-length solver to the nonlinear equation system,is developed and im-plemented in an in-house program. Three examples,i.e.,a plain concrete beam with a single shear crack,a reinforced concrete(RC) beam with multiple cracks and a compact-tension steel specimen,are simulated. Good agreement between numerical predictions and experimental data is found,which demonstrates the applicability of the criterion to both quasi-brittle and ductile materials.展开更多
通过数值模拟的方法,采用粘性区模型(cohesive zone model, CZM)研究了胶合木梁柱内嵌钢板-螺栓连接节点在单调荷载作用下的力学行为和开裂位移。在CZM中,通过横纹拉伸破坏(模式Ⅰ)、顺纹剪切破坏(模式Ⅱ)和两者的混合破坏模式(模式m)...通过数值模拟的方法,采用粘性区模型(cohesive zone model, CZM)研究了胶合木梁柱内嵌钢板-螺栓连接节点在单调荷载作用下的力学行为和开裂位移。在CZM中,通过横纹拉伸破坏(模式Ⅰ)、顺纹剪切破坏(模式Ⅱ)和两者的混合破坏模式(模式m)三种不同的模式,模拟了胶合木梁柱节点的横纹拉伸强度和顺纹剪切强度。结果表明,当加载位移达到1.2Δ~1.6Δ(Δ=90mm)时,胶合木梁柱节点上部,在木材顺纹方向沿两排螺栓连线位置发生横纹劈裂破坏。将数值模拟结果和已有试验结果进行了对比分析,发现二者具有很好的一致性,证明CZM在模拟胶合木梁柱节点的力学行为和开裂位移方面具有很好的适用性。展开更多
基金Project supported by the National Natural Science Foundation of China(Nos.U2241267,1217215511872195)。
文摘Cables composed of rare-earth barium copper oxide(REBCO)tapes have been extensively used in various superconducting devices.In recent years,conductor on round core(CORC)cable has drawn the attention of researchers with its outstanding current-carrying capacity and mechanical properties.The REBCO tapes are wound spirally on the surface of CORC cable.Under extreme loadings,the REBCO tapes with layered composite structures are vulnerable,which can lead to degradation of critical current and even quenching of superconducting devices.In this paper,we simulate the deformation of CORC cable under external loads,and analyze the damage inside the tape with the cohesive zone model(CZM).Firstly,the fabrication and cabling of CORC are simulated,and the stresses and strains generated in the tape are extracted as the initial condition of the next step.Then,the tension and bending loads are applied to CORC cable,and the damage distribution inside the tape is presented.In addition,the effects of some parameters on the damage are discussed during the bending simulations.
文摘This paper concentrates on simulating fracture in thin walled single-lap joints connected by resistance spot-welding(RSW)process which were subjected to tensile loading.For this purpose,three sets of lap-joints with different spot configurations were tested to achieve the joints’tensile behavior.To simulate the joints tensile behavior,firstly a 2D axisymmetric finite element(FE)model was used to calculate residual stresses induced during the welding process.Then the results were transferred to 3D models as pre-stress.In this step,cohesive zone model(CZM)technique was used to simulate fracture in the models under tensile load.Cohesive zone parameters were extracted using coach-peel and shear lap specimens.The results were employed to simulate deformation and failure in single lap spot weld samples.It has been shown that considering the residual stresses in simulating deformation and fracture load enables quite accurate predictions.
基金supported by the National Natural Science Foundation of China(No.11702147)。
文摘Investigation of paper cutting process is vital for the design of cutting tools,but the fracture mechanism of paper cutting is still unclear.Here,we focus on the cutting process of paper,including the key parameters of cohesive zone model(CZM)for the orthotropic paper,to simulate the shear fracture process.Firstly,the material constants of the orthotropic paper are determined by longitudinal and transverse tensile test.Secondly,based on the tensile stressstrain curves,combined with damage theory and numerical simulations,the key parameters of the CZM for the orthotropic paper are obtained.Finally,a model III fracture is simulated to verify the accuracy of the model.Results show that the load-displacement curves obtained by the simulation is consistent with the test results.
基金the Scientific Research Foundation for Re-turned Overseas Chinese Scholars, MOE (No. J20050924)the United Research Foundation of the National Natural Science Com-mittee and the Ertan Hydropower Development Co. Ltd., China (No. 50579081)
文摘Fully automatic finite element(FE) modelling of the fracture process in quasi-brittle materials such as concrete and rocks and ductile materials such as metals and alloys,is of great significance in assessing structural integrity and presents tre-mendous challenges to the engineering community. One challenge lies in the adoption of an objective and effective crack propagation criterion. This paper proposes a crack propagation criterion based on the principle of energy conservation and the cohesive zone model(CZM) . The virtual crack extension technique is used to calculate the differential terms in the criterion. A fully-automatic discrete crack modelling methodology,integrating the developed criterion,the CZM to model the crack,a simple remeshing procedure to accommodate crack propagation,the J2 flow theory implemented within the incremental plasticity framework to model the ductile materials,and a local arc-length solver to the nonlinear equation system,is developed and im-plemented in an in-house program. Three examples,i.e.,a plain concrete beam with a single shear crack,a reinforced concrete(RC) beam with multiple cracks and a compact-tension steel specimen,are simulated. Good agreement between numerical predictions and experimental data is found,which demonstrates the applicability of the criterion to both quasi-brittle and ductile materials.
文摘通过数值模拟的方法,采用粘性区模型(cohesive zone model, CZM)研究了胶合木梁柱内嵌钢板-螺栓连接节点在单调荷载作用下的力学行为和开裂位移。在CZM中,通过横纹拉伸破坏(模式Ⅰ)、顺纹剪切破坏(模式Ⅱ)和两者的混合破坏模式(模式m)三种不同的模式,模拟了胶合木梁柱节点的横纹拉伸强度和顺纹剪切强度。结果表明,当加载位移达到1.2Δ~1.6Δ(Δ=90mm)时,胶合木梁柱节点上部,在木材顺纹方向沿两排螺栓连线位置发生横纹劈裂破坏。将数值模拟结果和已有试验结果进行了对比分析,发现二者具有很好的一致性,证明CZM在模拟胶合木梁柱节点的力学行为和开裂位移方面具有很好的适用性。
