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91.
Yandong Wang Ziming Kou Guohua Cao 《Mathematical and Computer Modelling of Dynamical Systems: Methods, Tools and Applications in Engineering and Related Sciences》2020,26(3):253-267
ABSTRACT In this paper, a mathematical model is presented to numerically simulate the dynamical responses in a multi-cable suspension platform taking into account the slack cables and guiding devices. The state change of the cable (slack versus tensioned) is considered and is described mathematically by a complementary condition equation, and the interactions between the guiding wheels and the shaft wall are described by the Heaviside step function. The Lagrange’s equation with constraints is used to derive the dynamic equations of the system, and a non-smooth generalized-α algorithm for non-smooth phenomena of multibody dynamics is applied to numerically solve the equations. The simulation results have shown the dynamic responses of the platform and the cable tension characters when different cables are excited by different longitudinal excitations. Moreover, the results have illustrated how the cable tension differences may affect the pressure on the shaft wall applied by the guiding devices. 相似文献
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The degradation of cross-linked polyethylene (XLPE) insulation material is critical for the safe operation of cables. While there are extensive studies on the thermo-oxidative ageing of XLPE at or below 130 °C, the maximum overload conductor operating temperature, the short circuit temperature can rise above 150 °C, and the ageing patterns at these situations have not been fully understood. Here, chemical, crystalline structure, cross-linking density as well as the mechanical properties were characterized. The results demonstrate the importance of antioxidants in the high temperature situation. Before antioxidants are completely consumed, most of the mechanical and physicochemical properties remain stable. While antioxidant is depleted, the thermo-oxidative degradation is detrimental to the structure and properties of the insulation. The activation energy is around 160 kJ/mol for the thermo-oxidative ageing, from which the lifetime allowed before serious destruction of the insulation at different shortage or overload temperatures can be calculated. 相似文献
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自锚式悬索桥主缆状态影响参数分析 总被引:2,自引:0,他引:2
对自锚式悬索桥主缆的空缆状态和成桥状态进行了影响参数分析。以主缆线形、主缆对主索鞍水平分力和合力作用点位置为控制目标,定义了主缆合理成桥状态;以吉林市雾凇大桥为例,建立了主缆有限元模型。改变模型参数,计算主缆在不同参数下的空缆状态和成桥状态,并将其与基准状态进行比较,具体研究各影响参数对主缆状态的影响情况。主缆自重和空缆架设温度均对主缆状态影响甚微,中跨主缆无应力索长主要影响其自身线形,而边跨无应力索长会对各控制目标均造成较大影响;以空缆架设线形为控制条件时,发生在空缆架设前的主索鞍和后锚面位置偏差对主缆成桥状态不构成影响,但其发生在成桥运营阶段的变形会严重影响主缆成桥状态。工程实例分析结果表明,主缆抗拉刚度和成桥吊杆力均会对主缆成桥状态造成一定影响,建议在空缆架设前实测主缆抗拉刚度和梁段标准节间重量,控制两者偏差在合理范围内;建议对空缆架设线形设置预抬高,以抵消主索鞍和后锚面在成桥阶段的变形,该结论对自锚式悬索桥的空缆架设工作具有较强的指导意义和参考价值。 相似文献
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高温超导电缆终端恒温器是高温超导电缆终端系统的重要组成部分,其长期可靠稳定的运行将为整个系统的良好运转奠定坚实基础.文中对成功研制的高温超导电缆终端恒温器进行了详细介绍,包括技术指标及相关要求、总体结构、关键技术、热负荷分析与计算等.试验表明,高温超导电缆终端恒温器结构设计合理、操作方便;大口径可拆法兰低温真空压力环境下的密封技术得到突破、密封性能良好;低温液体输送管道承插密封结构设计新颖、满足工作要求.热负荷的分析与计算为高温超导电缆制冷系统所需冷量的确定提供了依据,同时也为终端恒温器的进一步优化指明了方向. 相似文献
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The external Q (Qext) of the dipole mode is a key parameter of the Cavity Beam Position Monitor (CBPM). It determines the amplitude and length of the dipole mode signal. In this paper, Qext of a CBPM whose waveguides were open to the air was simulated and measured, and the results agreed with each other. Then four waveguide-to-coaxial cable adpaters were adjusted and assembled to the CBPM, and Qext remained unchanged. This progress provides a reliable method to evaluate Qext in the physics design without si... 相似文献