桅杆风致破坏机理研究

桅杆风致破坏的情况屡见不鲜。桅杆的非线性是相当复杂的，它是由拉索的几何非线性和拉索的张力产生的，拉索的张力又依赖于拉索的几何位置。研究指出由于在经常性风荷载作用下，桅杆产生空间混沌振动，并由此产生疲劳破坏的结果，但这些研究仅限于确定性情况。本文中将研究扩展到随机问题，数值计算结果表明该系统存在随机混沌现象，其响应平均值与平均应力指出混沌性质。为了进一步研究桅杆破坏机理，因此在本文中，既考虑突发性故障问题，又考虑随机疲劳寿命问题，并给出时间与应力极值概率。

Study on Damage Mechanism of Mast under Wind Load

It is often seen that the mast under wind load has been damaged. Because the cables possess the geometric nonlinearity and the tension force depends on the geometric positions of cables, the nonlinearity of guyed mast is very complex. The recent researches have shown that in the frequent natural wind, the guyed masts may exhibit the spatial chaotic vibration, which can induce fatigue damage. But those works are limited on the deterministic case. In the real world, the wind velocity in nature has stochastic behavior, so that the investigation on the damage mechanisms of the guyed mast must consider the randomness of natural wind. This paper expands the problem into random field. Based on Chr. Peterson's and Peil s works, a guyed mast under stochastic wind load is considered and its random chaotic vibration is investigated. Because the spatial motion equations of guyed mast consist a set of differential equations and an algebraic equation, the analytic solution can not be obtained. In the paper, Houlbet's numerical integration method is applied to calculate the response of this system. The numerical results show that the guyed mast exhibits random chaotic behavior. Therefore, the mast may be damaged due to the random fatigue. From this, the random fatigue of this system is also studied by two methods: the sudden failure and the lifetime of random fatigue. The numerical results give the damage probablities of time and extreme stress of a typical cable.