输电塔结构风致疲劳分析
发布时间：2019-05-19 21:34
【摘要】：输电塔结构是一个国家生命线工程的重要组成部分，风荷载是其主要的设计荷载。近年来因风荷载造成的输电塔倒塌事故多次出现，不仅对人民的生产生活造成极大的影响，还可能导致其他比较严重的次生灾害。因此，对输电塔结构进行风振疲劳分析有着重要的现实工程意义。本文以龙开口500kV送出输电工程中呼高为45m的酒杯型输电塔为研究背景，详细地介绍了基于累积损伤理论和概率断裂力学理论的结构风振疲劳分析。 首先本文基于疲劳累计损伤理论，介绍了输电塔结构的风致疲劳时域分析方法，估算了结构的疲劳寿命。内容主要包括输电塔结构的有限元模型建立方法以及在随机风荷载作用下的了风振响应计算；并假定某风向上不同平均风速出现的概率服从Weibull分布，以考虑风向风速分布对结构疲劳累积损伤的影响。为减少计算机的计算量，本文运用材料力学知识提出了计算L型截面的应力分布的简化方法。 然后采用基于断裂力学的疲劳裂纹扩展模型对结构进行疲劳分析，而应力强度因子是一个重要的基本概念，反映了裂纹尖端附近应力场强弱。本文第三章主要介绍了三维表面裂纹有限元模型的建立和裂纹尖端处应力强度因子的求解方法，并将计算结果和NewmanRaju经验公式进行了对比，，以验证数值模拟的可行性和可靠性；并在此基础上提出了复合裂纹的应力强度因子的近似计算方法。 最后本文在第四章采用概率断裂力学理论研究结构的疲劳问题并考虑了材料裂纹扩展速率的随机性分散性。基于疲劳裂纹扩展理论和Paris公式，本章推导了恒幅荷载作用下结构的疲劳寿命估算公式，并通过引入一个平稳的对数正态随机过程获得随机裂纹扩展模型。
[Abstract]:Transmission tower structure is an important part of a national lifeline project, and wind load is its main design load. In recent years, the collapse of transmission tower caused by wind load has occurred many times, which not only has a great impact on the production and life of the people, but also may lead to other serious secondary disasters. Therefore, it is of great practical engineering significance to analyze the wind-induced vibration fatigue of transmission tower structure. In this paper, the wind-induced vibration fatigue analysis of the structure based on cumulative damage theory and probabilistic fracture mechanics theory is introduced in detail based on the research background of the wine glass transmission tower with 45m exhalation height in the transmission project sent out by long mouth 500kV. Firstly, based on the fatigue cumulative damage theory, the time domain analysis method of wind-induced fatigue of transmission tower structure is introduced, and the fatigue life of the structure is estimated. The content mainly includes the finite element model establishment method of transmission tower structure and the calculation of wind-induced vibration response under random wind load. It is assumed that the probability of different average wind speed in a certain wind direction obeys the Weibull distribution in order to consider the influence of wind direction and wind speed distribution on the fatigue cumulative damage of the structure. In order to reduce the computational complexity of computer, a simplified method for calculating the stress distribution of L-section is proposed by using the knowledge of material mechanics. Then the fatigue crack propagation model based on fracture mechanics is used to analyze the fatigue of the structure, and the stress intensity factor is an important basic concept, which reflects the stress field near the crack tip. In the third chapter, the establishment of three-dimensional surface crack finite element model and the solution method of stress intensity factor at crack tip are introduced, and the calculated results are compared with NewmanRaju empirical formula to verify the feasibility and reliability of numerical simulation. On this basis, an approximate calculation method of stress intensity factor of composite crack is put forward. Finally, in the fourth chapter, the fatigue problem of the structure is studied by using the probabilistic fracture mechanics theory, and the random dispersion of the crack growth rate of the material is considered. Based on the fatigue crack growth theory and Paris formula, the fatigue life estimation formula of the structure under constant amplitude load is derived in this chapter, and the random crack propagation model is obtained by introducing a stationary lognormal stochastic process.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU347;TU312
本文编号：2481083
[Abstract]:Transmission tower structure is an important part of a national lifeline project, and wind load is its main design load. In recent years, the collapse of transmission tower caused by wind load has occurred many times, which not only has a great impact on the production and life of the people, but also may lead to other serious secondary disasters. Therefore, it is of great practical engineering significance to analyze the wind-induced vibration fatigue of transmission tower structure. In this paper, the wind-induced vibration fatigue analysis of the structure based on cumulative damage theory and probabilistic fracture mechanics theory is introduced in detail based on the research background of the wine glass transmission tower with 45m exhalation height in the transmission project sent out by long mouth 500kV. Firstly, based on the fatigue cumulative damage theory, the time domain analysis method of wind-induced fatigue of transmission tower structure is introduced, and the fatigue life of the structure is estimated. The content mainly includes the finite element model establishment method of transmission tower structure and the calculation of wind-induced vibration response under random wind load. It is assumed that the probability of different average wind speed in a certain wind direction obeys the Weibull distribution in order to consider the influence of wind direction and wind speed distribution on the fatigue cumulative damage of the structure. In order to reduce the computational complexity of computer, a simplified method for calculating the stress distribution of L-section is proposed by using the knowledge of material mechanics. Then the fatigue crack propagation model based on fracture mechanics is used to analyze the fatigue of the structure, and the stress intensity factor is an important basic concept, which reflects the stress field near the crack tip. In the third chapter, the establishment of three-dimensional surface crack finite element model and the solution method of stress intensity factor at crack tip are introduced, and the calculated results are compared with NewmanRaju empirical formula to verify the feasibility and reliability of numerical simulation. On this basis, an approximate calculation method of stress intensity factor of composite crack is put forward. Finally, in the fourth chapter, the fatigue problem of the structure is studied by using the probabilistic fracture mechanics theory, and the random dispersion of the crack growth rate of the material is considered. Based on the fatigue crack growth theory and Paris formula, the fatigue life estimation formula of the structure under constant amplitude load is derived in this chapter, and the random crack propagation model is obtained by introducing a stationary lognormal stochastic process.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU347;TU312
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