为了分析某中承式钢管混凝土桁式拱肋节点疲劳开裂的原因,运用有限元软件MIDAS/CIVIL建立全桥模型进行有限元分析。分别研究了不同车辆荷载和不同拱肋节点几何参数情况下拱肋节点应力幅的变化,进而分析了车辆超载和车辆中、偏载布置对...为了分析某中承式钢管混凝土桁式拱肋节点疲劳开裂的原因,运用有限元软件MIDAS/CIVIL建立全桥模型进行有限元分析。分别研究了不同车辆荷载和不同拱肋节点几何参数情况下拱肋节点应力幅的变化,进而分析了车辆超载和车辆中、偏载布置对拱肋节点应力幅的影响,并讨论了拱肋节点几何参数变化对拱肋节点应力幅的影响。研究表明,当车辆荷载超载30%、50%、100%和150%时拱肋节点应力幅基本呈线性增大,应力幅最大值达155 MPa。BS5400疲劳车辆荷载作用下拱肋节点应力幅最大,中国550 k N车辆荷载偏载作用下拱肋节点应力幅为中载1.2倍。超载和偏载分别是造成该钢管混凝土桁式拱桥拱肋节点出现疲劳开裂和疲劳裂缝分布不对称的主要原因。节点应力幅随弦杆和腹杆间壁厚比的增大而减小,而随弦杆和腹杆间管径比、弦杆径厚比和腹杆径厚比的增大表现为先增大后减小的趋势。展开更多
Battery energy storage system(BESS)has already been studied to deal with uncertain parameters of the electrical systems such as loads and renewable energies.However,the BESS have not been properly studied under unbala...Battery energy storage system(BESS)has already been studied to deal with uncertain parameters of the electrical systems such as loads and renewable energies.However,the BESS have not been properly studied under unbalanced operation of power grids.This paper aims to study the modelling and operation of BESS under unbalanced-uncertain conditions in the power grids.The proposed model manages the BESS to optimize energy cost,deal with load uncertainties,and settle the unbalanced loading at the same time.The three-phase unbalanced-uncertain loads are modelled and the BESSs are utilized to produce separate charging/discharging pattern on each phase to remove the unbalanced condition.The IEEE 69-bus grid is considered as case study.The load uncertainty is developed by Gaussian probability function and the stochastic programming is adopted to tackle the uncertainties.The model is formulated as mixed-integer linear programming and solved by GAMS/CPLEX.The results demonstrate that the model is able to deal with the unbalanced-uncertain conditions at the same time.The model also minimizes the operation cost and satisfies all security constraints of power grid.展开更多
文摘为了分析某中承式钢管混凝土桁式拱肋节点疲劳开裂的原因,运用有限元软件MIDAS/CIVIL建立全桥模型进行有限元分析。分别研究了不同车辆荷载和不同拱肋节点几何参数情况下拱肋节点应力幅的变化,进而分析了车辆超载和车辆中、偏载布置对拱肋节点应力幅的影响,并讨论了拱肋节点几何参数变化对拱肋节点应力幅的影响。研究表明,当车辆荷载超载30%、50%、100%和150%时拱肋节点应力幅基本呈线性增大,应力幅最大值达155 MPa。BS5400疲劳车辆荷载作用下拱肋节点应力幅最大,中国550 k N车辆荷载偏载作用下拱肋节点应力幅为中载1.2倍。超载和偏载分别是造成该钢管混凝土桁式拱桥拱肋节点出现疲劳开裂和疲劳裂缝分布不对称的主要原因。节点应力幅随弦杆和腹杆间壁厚比的增大而减小,而随弦杆和腹杆间管径比、弦杆径厚比和腹杆径厚比的增大表现为先增大后减小的趋势。
文摘Battery energy storage system(BESS)has already been studied to deal with uncertain parameters of the electrical systems such as loads and renewable energies.However,the BESS have not been properly studied under unbalanced operation of power grids.This paper aims to study the modelling and operation of BESS under unbalanced-uncertain conditions in the power grids.The proposed model manages the BESS to optimize energy cost,deal with load uncertainties,and settle the unbalanced loading at the same time.The three-phase unbalanced-uncertain loads are modelled and the BESSs are utilized to produce separate charging/discharging pattern on each phase to remove the unbalanced condition.The IEEE 69-bus grid is considered as case study.The load uncertainty is developed by Gaussian probability function and the stochastic programming is adopted to tackle the uncertainties.The model is formulated as mixed-integer linear programming and solved by GAMS/CPLEX.The results demonstrate that the model is able to deal with the unbalanced-uncertain conditions at the same time.The model also minimizes the operation cost and satisfies all security constraints of power grid.
