多索索道承载索耦合计算方法及安全性评估

Calculation method of the coupled loading-cables and safety assessment for the multi-cable cableway

分析双承载索、四承载索货运索道的承载索、牵引索及运行小车之间的相互作用关系,提出承载索与运行小车的位移耦合约束方程,并在有限质点法理论的基础上,建立了承载索、牵引索、运行小车的运动方程,提出了适用于双承载索、四承载索货运索道的承载索结构耦合计算方法,形成计算流程。采用该方法进行多索索道承载索安全性能分析,根据实际工程中货运索道承载钢丝绳的蠕变伸长现象,制定了覆盖双索和四索货运索道承载索长度变化的组合工况,进行了承载索张力计算。结果表明,各承载索的最大张力对索长变化极为敏感,较小的长度变化即可引起承载索间张力的极大偏差,造成索道整体结构安全系数的降低。根据多索张力耦合计算结果提出了适用于多索索道设计的承载索设计安全系数取值建议。

This paper is intended to make an analysis of the interaction of the loading cables,the traction cable and the travelling trolleys of the freight cableway consisting of the double and 4 loading-cables. And,next,it would like to propose a calculation method for the coupled loading-cables for the multi-cable cableway based on the theory of the finite particle method,so that the loading cables and traction cables of the multi-cable cableway can be discretized into a series of particles. According to Newton’s second law,it can establish a translation equation of the loading cable particles and the traction cable particles with the rotation equations of the travelling trolley particles. At the same time,it would also be possible to establish the displacement coupling constraint equations of the loading cables,the traction cable and the travelling trolleys according to their interaction. Furthermore,it is also necessary to work out the force and the displacement results of the loading cable,the traction cable and the travelling trolley to solve the particle motion equations step by step by using the central difference method,so as to fulfil the entire calculation process. Thus,it can be seen that the above mentioned method can be applied to analyze the safety of the multi-cable way loading cables. And,in accordance with the creep elongation phenomenon of the loading steel cable-wire for the freight cableway in the engineering practice,it would also be possible to formulate the combined working cases to cover the changing needs of the length of the loading cables in the double loading-cable cableway and the 4 loading-cables cableway,so that the tension of the loading-cables can be worked out according to the actual cases to be needed. The results of our research indicate that the maximum tension of each loading cable in the multi-cable freight cableways tends to be extremely sensitive to the change of the cable length. Even a little change of the loading-cable length may result in the obvious and distinctive deviation of the tension between the different loading cables and lead to the decrease of the safety factors of the entire cableway structure. And,finally,we would like to provide the above recommended safety factor reference versions for the loading cable design in the multi-cable cableway on the basis of summerizing the results of the multi-cable tension coupling calculation.