结构系统风致疲劳寿命可靠性分析

Wind-induced fatigue life reliability analysis of structural systems

工程结构一般是由很多构件组成的超静定结构。在风荷载作用下,一个或者几个构件发生风致疲劳破坏不一定导致结构系统失效。首先,结合风速风向联合分布等风荷载特征,给出计算结构系统风致疲劳寿命失效概率的计算流程。其次,由风洞试验结果对目前世界最高的电视塔——610m的广州新电视塔的天线结构进行风振响应分析,风振响应计算中考虑塔身结构的振动对天线结构响应的影响。最后,在以上两步分析的基础上,对该天线结构系统的风致疲劳寿命可靠性进行计算。计算结果表明:用阶段疲劳寿命分枝-约界法识别出17个主要失效模式;S-N曲线中随机变量的参数对主要失效模式的失效概率影响较大;用蒙特卡罗方法计算的100年设计寿命相应的这一实际天线结构的风致疲劳失效概率为4.2%左右。

A complex structure system is commonly a statically indeterminate structure composed of numerous frame members. Such structure system may not fail even after one or some members are wrecked due to wind-induced fatigue. In this paper, a method for the failure probability of structural systems under wind action is presented, considering the joint probability distribution of wind speed and direction. Wind-induced response of the antenna of the Guangzhou New TV Tower, presently the tallest TV tower in the world, is computed with the effects of wind-induced vibration of the tower body on the antenna taken into account, and the results are compared with the results of wind tunnel test. The wind - induced fatigue life reliability of the antenna is computed using the computation flow chart for the failure probability of structural systems. Seventeen primary fatigue failure modes are identified. The computation results indicate that the parameters of S-N curve have great effects on the failure probability of the primary failure mode. The wind-induced failure probability of the antenna of the Guangzhou New TV Tower is about 4.2 % for one hundred years of design life.