Sequence placement logic plays a significant role in construction simulation of high arch dams and directly affects the simulation process and results.To establish a sequence logic for dam block placement,the construc...Sequence placement logic plays a significant role in construction simulation of high arch dams and directly affects the simulation process and results.To establish a sequence logic for dam block placement,the construction scheme,real-time construction process,and random factors of the site all need to be considered in detail.There are few studies available currently that take all these factors into consideration.To address this problem,a real-time update of sequence placement logic for high arch dams based on evidence weight discount is proposed in this study.First,the subjective weight of the dam block sequence priority criteria is built using a consistent matrix method based on the construction scheme.Second,using evidence theory,dynamic objective weight of the priority criteria and basic probability assignment is built.Finally,using a weight self-adaptive adjustment method and comprehensive evidence discounting,the placing probabilities of different dam blocks are obtained.A case study indicates that this method can realize realtime update of sequence placement logic.展开更多
In real-time hybrid simulation（RTHS）, it is difficult if not impossible to completely erase the error in restoring force due to actuator response delay using existing displacement-based compensation methods. This pa...In real-time hybrid simulation（RTHS）, it is difficult if not impossible to completely erase the error in restoring force due to actuator response delay using existing displacement-based compensation methods. This paper proposes a new force correction method based on online discrete tangent stiffness estimation（online DTSE） to provide accurate online estimation of the instantaneous stiffness of the physical substructure. Following the discrete curve parameter recognition theory, the online DTSE method estimates the instantaneous stiffness mainly through adaptively building a fuzzy segment with the latest measurements, constructing several strict bounding lines of the segment and calculating the slope of the strict bounding lines, which significantly improves the calculation efficiency and accuracy for the instantaneous stiffness estimation. The results of both computational simulation and real-time hybrid simulation show that：（1） the online DTSE method has high calculation efficiency, of which the relatively short computation time will not interrupt RTHS; and（2） the online DTSE method provides better estimation for the instantaneous stiffness, compared with other existing estimation methods. Due to the quick and accurate estimation of instantaneous stiffness, the online DTSE method therefore provides a promising technique to correct restoring forces in RTHS.展开更多
In the paper, the optimal self-scaling strategy to the modified symmetric rank one (HSR1) update, which satisfies the modified quasi-Newton equation, is derived to improve the condition number of the updates. The scal...In the paper, the optimal self-scaling strategy to the modified symmetric rank one (HSR1) update, which satisfies the modified quasi-Newton equation, is derived to improve the condition number of the updates. The scaling factors are derived from minimizing the estimate of upper bounds on the condition number of the updating matrix. Theoretical analysis, and numerical experiments and comparisons show that introducing the optimal scaling factor into the modified symmetric rank one update preserves the positive definiteness of updates, and greatly improves the stability and numerical performance of the modified symmetric rank one algorithm.展开更多
基金supported by the Foundation for Innovative Research Groups of National Natural Science Foundation of China(No.51321065)the Foundation for Key Program of Natural Science Foundation of High Arch Dam(No.51339003)the National Basic Research Program of China(‘‘973’’Program,No.2013CB035904)
文摘Sequence placement logic plays a significant role in construction simulation of high arch dams and directly affects the simulation process and results.To establish a sequence logic for dam block placement,the construction scheme,real-time construction process,and random factors of the site all need to be considered in detail.There are few studies available currently that take all these factors into consideration.To address this problem,a real-time update of sequence placement logic for high arch dams based on evidence weight discount is proposed in this study.First,the subjective weight of the dam block sequence priority criteria is built using a consistent matrix method based on the construction scheme.Second,using evidence theory,dynamic objective weight of the priority criteria and basic probability assignment is built.Finally,using a weight self-adaptive adjustment method and comprehensive evidence discounting,the placing probabilities of different dam blocks are obtained.A case study indicates that this method can realize realtime update of sequence placement logic.
基金Priority Academic Program Development of Jiangsu Higher Education Institutions under Grant No.1105007002National Natural Science Foundation of China under Grant No.51378107 and No.51678147
文摘In real-time hybrid simulation（RTHS）, it is difficult if not impossible to completely erase the error in restoring force due to actuator response delay using existing displacement-based compensation methods. This paper proposes a new force correction method based on online discrete tangent stiffness estimation（online DTSE） to provide accurate online estimation of the instantaneous stiffness of the physical substructure. Following the discrete curve parameter recognition theory, the online DTSE method estimates the instantaneous stiffness mainly through adaptively building a fuzzy segment with the latest measurements, constructing several strict bounding lines of the segment and calculating the slope of the strict bounding lines, which significantly improves the calculation efficiency and accuracy for the instantaneous stiffness estimation. The results of both computational simulation and real-time hybrid simulation show that：（1） the online DTSE method has high calculation efficiency, of which the relatively short computation time will not interrupt RTHS; and（2） the online DTSE method provides better estimation for the instantaneous stiffness, compared with other existing estimation methods. Due to the quick and accurate estimation of instantaneous stiffness, the online DTSE method therefore provides a promising technique to correct restoring forces in RTHS.
文摘In the paper, the optimal self-scaling strategy to the modified symmetric rank one (HSR1) update, which satisfies the modified quasi-Newton equation, is derived to improve the condition number of the updates. The scaling factors are derived from minimizing the estimate of upper bounds on the condition number of the updating matrix. Theoretical analysis, and numerical experiments and comparisons show that introducing the optimal scaling factor into the modified symmetric rank one update preserves the positive definiteness of updates, and greatly improves the stability and numerical performance of the modified symmetric rank one algorithm.
