输电塔线体系的风(雨)致振动响应与稳定性研究

根据输电塔线体系在风(雨)激励下破坏的实际状况,建立了"三塔两跨"有限元分析模型,其中,输电塔采用三自由度梁单元,导(地)线采用索单元;提出雨荷载的计算方法以及与风湍流共同作用于输电塔线体系的荷载组合原则;分析输电塔、导(地)线和结构体系的结构动力特性及其相互关系;采用数值模拟方法,建立设计与灾害荷载的不同工况组合,分别在时域和频域内对输电塔的动力响应规律进行分析;采用结构主要组件(如主立柱杆件和输电线)强度分析的方法,分析结构强度的变化和灾害发生的可能性原因。研究表明:输电塔线体系的运动耦合性对结构动力特性有不容忽视的影响;降雨对输电塔线体系的响应具有明显影响,且有与风湍流同时作用的激励特征;结构体系发生连续倒塔破坏的原因是风雨共同作用,结构局部动态受压失稳造成的。

Dynamic behavior and stability of transmission tower-line system under wind (rain) forces

Based on the actual failure states of specific transmission tower-line system(TTLS)under wind(rain)excitations,a three-tower and two-span finite element model is supposed,in which the transmission tower is modeled as three-degree beam element,and the conductor(or ground line)is modeled as cable element.A calculation method is presented for rain force and its superposition with wind.The structural dynamic characteristics of transmission tower,conductors(or ground lines)and TTLS and their relationships are analyzed.According to different design and disaster loading combinations,the dynamic response of transmission tower is studied in the time domain and the frequency domain,respectively.Variations of sub-structural intensities and possible reasons for disaster occurrence are discussed by using a strength analytical method for the main structural composite members(such as the post members and transmission lines).The results indicate:the coupling properties of TTLS have non-negligible influence on structural dynamic properties;the rain-wind excitation have effects on the responses of TTLS distinctively different from wind load alone;the cause for structural consecutive collapse is wind and rain combined excitation that makes partial TTLS loss its dynamic stability.