基于机构运动及磨损理论的伸缩装置滑动支承磨损评估方法

为评估运营阶段风及车流作用下大跨桥梁转轴式伸缩装置的服役状态，融合机构运动理论及磨损机理建立转轴式伸缩装置滑动支承构件的磨损寿命评估方法。以变杆长双滑块双导杆四连杆机构的运动理论为基础，推导了多滑块多导杆的伸缩装置机构运动学数值仿真模型；基于Archard磨损理论提出了伸缩装置滑动支承磨损深度计算模型，以失效概率为指标建立了伸缩装置滑动支承磨损寿命的评估方法；以一单跨悬索桥为算例，对风和车流作用下伸缩装置滑动支承的服役年限及其年更换次数进行定量评估。分析结果表明：建立伸缩装置的机构运动仿真模型，通过与8缝伸缩机构的运动试验数据对比，验证了仿真模型的准确性；利用伽马分布能够较好地模拟伸缩装置滑动支承磨损深度的累加概率特性；随机车流和风作用下，悬索桥伸缩装置滑动支承的服役年限随距滑动侧越近而越小，失效概率反之；一般流和风速10 m·s^-1工况下，超82%的滑动支承服役年限小于15年；不同车流密度-风速联合作用对伸缩装置滑动支承的服役年限影响显著，伸缩装置滑动支承的合理更换周期应依据桥址交通量荷载水平及风场条件制定；建立的转轴式伸缩装置滑动支承磨损寿命评估方法可为同类型伸缩装置机构的磨损寿命评估提供参考借鉴。

Method of Wear Evaluation on Sliding Supports in Expansion Joints Based on Theories of Mechanism Motion and Wear

To evaluate the service state of the large-displacement swivel joist expansion joints under the action of traffic flow and wind loads during the operation period, the wear life evaluation method of the expansion joints component was established based on the combination of mechanism motion and wear theory of the mechanism. Based on the motion theory of variable length double rocker and slider four-bar linkage, the kinematics model of multi rocker and slider expansion joints mechanism was established. The wear depth calculation model of sliding supports in expansion joints was proposed based on Archard wear theory, and the evaluation method of wear life of sliding supports in expansion joints was established with index of failure probability. Taking a single span suspension bridge as an example, the service life and annual replacement times of sliding supports in expansion joints were quantitatively evaluated. The results indicated that movement simulation model of expansion joints has been established. By comparing with the motion test data of the 8-joints expansion mechanism, the accuracy of the simulation model was verified. The cumulative distributed probability characteristics of the wear depth of sliding supports in expansion joints could be simulated by using the gamma distribution. Under the action of random traffic flow and wind loads, the service life of the expansion joints sliding support of suspension bridge decreased with the closer to the sliding side, and the failure probability was on the contrary. The service life of more than 82% sliding supports was less than 15 years under the general flow and wind speed conditions of 10 m·s^-1. The combined action of different traffic densities and wind speeds had a great influence on the service life of sliding supports in expansion joints, and it is suggested that a reasonable replacement period for sliding supports in expansion joints should be formulated according to the traffic load level and wind field condition. The established wear life evaluation method of rotary shaft expansion joints could provide reference for the wear life evaluation of the same type expansion joints mechanism.