With increasing water depth,marine drilling conductors exhibit higher slenderness ratios,significantly reducing their resistance to environmental loads in Arctic waters.These conductors,when subjected to combined wind...With increasing water depth,marine drilling conductors exhibit higher slenderness ratios,significantly reducing their resistance to environmental loads in Arctic waters.These conductors,when subjected to combined wind,current,and ice loads,may experience substantial horizontal displacements and bending moments,potentially compromising off-shore operational safety and wellhead stability.Additionally,soil disturbance near the mudline diminishes the conductor’s bearing capacity,potentially rendering it inadequate for wellhead support and increasing operational risks.This study introduces a static analysis model based on plastic hinge theory to evaluate conductor survivability.The conductor analysis divides the structure into three segments:above waterline,submerged,and embedded below mudline.An idealized elastic-plastic p-y curve model characterizes soil behavior beneath the mudline,while the finite difference method(FDM)analyzes the conductor’s mechanical response under complex pile-head boundary conditions.Numerical simulations using ABAQUS validate the plastic hinge approach against conventional methods,confirming its accuracy in predicting structural performance.These results provide valuable insights for optimizing installation depths and bearing capacity designs of marine drilling conductors in ice-prone regions.展开更多
Opening horizontal slit in the middle web of the beam end formed a new type of artificial plastic hinge. The calculation formulas about the hinge’s interior force and bearing capacity are set up. Based on these, the ...Opening horizontal slit in the middle web of the beam end formed a new type of artificial plastic hinge. The calculation formulas about the hinge’s interior force and bearing capacity are set up. Based on these, the condition of transfer, the location of crack and the cracking length of the artificial plastic hinge were studied further. The calculation method for the ductility factor was also presented. The calculation results and the test ones were compatible.展开更多
The accuracy and effi ciency of the modelling techniques utilized to model the nonlinear behavior of structural components is a signifi cant issue in earthquake engineering. In this study, the suffi ciency of three di...The accuracy and effi ciency of the modelling techniques utilized to model the nonlinear behavior of structural components is a signifi cant issue in earthquake engineering. In this study, the suffi ciency of three diff erent modelling techniques that can be employed to simulate the structural behavior of columns is investigated. A fi ber-based fi nite length plastic hinge (FB-FLPH) model is calibrated in this study. In order to calibrate the FB-FLPH model, a novel database of the cyclic behavior of hollow steel columns under simultaneous axial and lateral loading cycles with varying amplitudes is used. By employing the FB-FLPH model calibrated in this study, the interaction of the axial force and the bending moment in columns is directly taken into account, and the deterioration in the cyclic behavior of these members is implicitly considered. The superiority of the calibrated FB-FLPH modelling approach is examined compared with the cases in which conventional fi ber-based distributed plasticity and concentrated plasticity models are utilized. The effi ciency of the enumerated modelling techniques is probed when they are implemented to model the columns of a typical special moment frame in order to prove the advantage of the FB-FLPH modelling approach.展开更多
An efficient approach is proposed for the equivalent linearization of frame structures with plastic hinges under nonstationary seismic excitations.The concentrated plastic hinges,described by the Bouc-Wen model,are as...An efficient approach is proposed for the equivalent linearization of frame structures with plastic hinges under nonstationary seismic excitations.The concentrated plastic hinges,described by the Bouc-Wen model,are assumed to occur at the two ends of a linear-elastic beam element.The auxiliary differential equations governing the plastic rotational displacements and their corresponding hysteretic displacements are replaced with linearized differential equations.Then,the two sets of equations of motion for the original nonlinear system can be reduced to an expanded-order equivalent linearized equation of motion for equivalent linear systems.To solve the equation of motion for equivalent linear systems,the nonstationary random vibration analysis is carried out based on the explicit time-domain method with high efficiency.Finally,the proposed treatment method for initial values of equivalent parameters is investigated in conjunction with parallel computing technology,which provides a new way of obtaining the equivalent linear systems at different time instants.Based on the explicit time-domain method,the key responses of interest of the converged equivalent linear system can be calculated through dimension reduction analysis with high efficiency.Numerical examples indicate that the proposed approach has high computational efficiency,and shows good applicability to weak nonlinear and medium-intensity nonlinear systems.展开更多
为了解决传统装配式预应力框架梁柱节点耗能件施工困难、成本高昂等问题,提出了一种基于塑性铰转移的后张预应力装配式干式连接混凝土框架(post-tensioned precast concrete frames based on plastic hinge relocation,PPFBP).首先,基于...为了解决传统装配式预应力框架梁柱节点耗能件施工困难、成本高昂等问题,提出了一种基于塑性铰转移的后张预应力装配式干式连接混凝土框架(post-tensioned precast concrete frames based on plastic hinge relocation,PPFBP).首先,基于PPFBP梁柱节点试验结果,建立相应的梁单元模型,验证了建模方法的可行性及合理性.然后,设计并建立5层PPFBP及普通现浇框架有限元模型,结合静力弹塑性分析法与动力时程分析法对PPFBP抗震性能进行分析研究.研究结果表明:新型预应力框架结构在不同侧力模式下顶点位移与基底剪力有较大的差异;在相同侧力模式下,新型预应力框架结构层间位移角均能满足规范中的限值要求,较现浇混凝土框架结构有着显著的下降,各层层间位移角变化均匀,无明显薄弱层;动力时程分析法结果与静力弹塑性分析法吻合,新型预应力框架通过合理控制塑性铰位置,使结构成为完全梁铰耗能屈服机制,具有良好的抗震性能.展开更多
基金financially supported by the National Natural Science Foundation of China(Grant No.U22B20126)the National Key Research and Development Program of China(Grant No.2022YFC2806100).
文摘With increasing water depth,marine drilling conductors exhibit higher slenderness ratios,significantly reducing their resistance to environmental loads in Arctic waters.These conductors,when subjected to combined wind,current,and ice loads,may experience substantial horizontal displacements and bending moments,potentially compromising off-shore operational safety and wellhead stability.Additionally,soil disturbance near the mudline diminishes the conductor’s bearing capacity,potentially rendering it inadequate for wellhead support and increasing operational risks.This study introduces a static analysis model based on plastic hinge theory to evaluate conductor survivability.The conductor analysis divides the structure into three segments:above waterline,submerged,and embedded below mudline.An idealized elastic-plastic p-y curve model characterizes soil behavior beneath the mudline,while the finite difference method(FDM)analyzes the conductor’s mechanical response under complex pile-head boundary conditions.Numerical simulations using ABAQUS validate the plastic hinge approach against conventional methods,confirming its accuracy in predicting structural performance.These results provide valuable insights for optimizing installation depths and bearing capacity designs of marine drilling conductors in ice-prone regions.
文摘Opening horizontal slit in the middle web of the beam end formed a new type of artificial plastic hinge. The calculation formulas about the hinge’s interior force and bearing capacity are set up. Based on these, the condition of transfer, the location of crack and the cracking length of the artificial plastic hinge were studied further. The calculation method for the ductility factor was also presented. The calculation results and the test ones were compatible.
文摘The accuracy and effi ciency of the modelling techniques utilized to model the nonlinear behavior of structural components is a signifi cant issue in earthquake engineering. In this study, the suffi ciency of three diff erent modelling techniques that can be employed to simulate the structural behavior of columns is investigated. A fi ber-based fi nite length plastic hinge (FB-FLPH) model is calibrated in this study. In order to calibrate the FB-FLPH model, a novel database of the cyclic behavior of hollow steel columns under simultaneous axial and lateral loading cycles with varying amplitudes is used. By employing the FB-FLPH model calibrated in this study, the interaction of the axial force and the bending moment in columns is directly taken into account, and the deterioration in the cyclic behavior of these members is implicitly considered. The superiority of the calibrated FB-FLPH modelling approach is examined compared with the cases in which conventional fi ber-based distributed plasticity and concentrated plasticity models are utilized. The effi ciency of the enumerated modelling techniques is probed when they are implemented to model the columns of a typical special moment frame in order to prove the advantage of the FB-FLPH modelling approach.
基金Fundamental Research Funds for the Central Universities under Grant No.2682022CX072the Research and Development Plan in Key Areas of Guangdong Province under Grant No.2020B0202010008。
文摘An efficient approach is proposed for the equivalent linearization of frame structures with plastic hinges under nonstationary seismic excitations.The concentrated plastic hinges,described by the Bouc-Wen model,are assumed to occur at the two ends of a linear-elastic beam element.The auxiliary differential equations governing the plastic rotational displacements and their corresponding hysteretic displacements are replaced with linearized differential equations.Then,the two sets of equations of motion for the original nonlinear system can be reduced to an expanded-order equivalent linearized equation of motion for equivalent linear systems.To solve the equation of motion for equivalent linear systems,the nonstationary random vibration analysis is carried out based on the explicit time-domain method with high efficiency.Finally,the proposed treatment method for initial values of equivalent parameters is investigated in conjunction with parallel computing technology,which provides a new way of obtaining the equivalent linear systems at different time instants.Based on the explicit time-domain method,the key responses of interest of the converged equivalent linear system can be calculated through dimension reduction analysis with high efficiency.Numerical examples indicate that the proposed approach has high computational efficiency,and shows good applicability to weak nonlinear and medium-intensity nonlinear systems.
文摘为了解决传统装配式预应力框架梁柱节点耗能件施工困难、成本高昂等问题,提出了一种基于塑性铰转移的后张预应力装配式干式连接混凝土框架(post-tensioned precast concrete frames based on plastic hinge relocation,PPFBP).首先,基于PPFBP梁柱节点试验结果,建立相应的梁单元模型,验证了建模方法的可行性及合理性.然后,设计并建立5层PPFBP及普通现浇框架有限元模型,结合静力弹塑性分析法与动力时程分析法对PPFBP抗震性能进行分析研究.研究结果表明:新型预应力框架结构在不同侧力模式下顶点位移与基底剪力有较大的差异;在相同侧力模式下,新型预应力框架结构层间位移角均能满足规范中的限值要求,较现浇混凝土框架结构有着显著的下降,各层层间位移角变化均匀,无明显薄弱层;动力时程分析法结果与静力弹塑性分析法吻合,新型预应力框架通过合理控制塑性铰位置,使结构成为完全梁铰耗能屈服机制,具有良好的抗震性能.
