High pole light is a common facility for urban road lighting, because the high pole light tower belongs to the towering tower. Wind load has a great influence on the stability of tall pole lamps, which are slender and self-supporting vertical structures. In windy coastal areas, the cyclic stress caused by wind-induced vibration may lead to fatigue damage and even failure of high pole lamp structures. In recent years, due to the frequent overturning accidents of high pole lamps, it has also caused relatively serious personnel and property losses. There are many reasons for the safety accidents of high pole lamps, but the wind load overload caused by structural fatigue is one of the important reasons. Because Zhoushan Islands is located in the ocean, and extreme weather conditions such as rainstorm and typhoon occur frequently, high pole lamp safety accidents are more likely to occur. This study estimates the wind-induced fatigue life of high pole lighthouses in time domain based on the random fatigue theory and the time history simulation of random wind vibration response, and analyzes the reliability of high pole lamps, The fatigue life and damage rule of the lighthouse are obtained.

2. In the practical application of the time history simulation method of basic wind vibration response, it is found that the biggest and most critical factor affecting the intensity of high pole lamps is the wind load. The average wind and fluctuating wind constitute the natural wind, and the fluctuating wind is one of the causes of wind vibration and wind-induced fatigue of structures, and its strength changes with time according to the random law. According to the structure of the tower and different wind vibration mechanisms, the wind vibration response of the tower is usually divided into two directions, namely, along wind direction and across wind direction. At present, the time history simulation method of wind vibration response is relatively mature in the downwind direction. Time history samples of fluctuating wind load can be obtained through numerical simulation methods of stationary random processes such as harmonic superposition method and autoregression method, and then the time history response of wind vibration can be obtained through dynamic analysis method. Under the action of wind, vortices will be generated alternately on both sides of the leeward side of the tower placed in the open air, and then separate and form a row of clockwise and a row of counterclockwise regular vortex wake, which is called Karman vortex street (or vortex train). The alternating generation and separation of Karman vortex street makes tower equipment vibrate in the direction perpendicular to the wind direction. Once the natural frequency and vibration frequency of the tower equipment are equal, it will cause resonance, make the tower equipment shake, and even make the tower equipment invalid. Compared with the crosswind wind-induced response, the downwind wind-induced response is generally similar, except that the crosswind wind-induced response mechanism is more complex.

Therefore, the time history simulation of crosswind wind-induced vibration response can still be generally carried out as the downwind simulation method, but the simulation details are more cumbersome. The theoretical basis for simulating the crosswind wind-induced vibration response in this paper is based on the superposition of the loads caused by vortex shedding in the wake of static structures and the loads caused by incoming turbulence, which are caused by the towering tower. Assuming that the two excitations are independent of each other, the crosswind wind load power spectrum matrix S L in the numerical simulation method of stationary random process can be written as follows: S L! In the SLz+SLZ formula, SLI is the vortex shedding load spectrum matrix, and SLZ is the incoming turbulence load spectrum matrix. The above formula is only applicable to the load borne by the tower when the vibration is small. If the tower body vibrates greatly due to resonance, the influence of aeroelasticity must be considered. At this time, the total damping ratio of the structure is: Tun=Yan+Ho. In the formula, it is the total damping ratio, Mao is the structural damping ratio, and it is the aerodynamic damping ratio. Calculation of the natural vibration period of the light tower The natural vibration period of the basic vibration mode of tower equipment with symmetrical structure and approximately uniformly distributed mass along the height can be calculated according to the following formula:; When the basic data of tower equipment cannot be directly measured, T o can be used instead of T in the absence of some basic data. Because part of the data of the 25M semi-automatic lifting high pole lamp on Linchang Road is missing, this paper uses TO instead of T. Through calculation, the natural vibration period of the basic mode of the 25M semi-automatic lifting high pole lamp on Linchang Road is 0.05655.