| Quayside crane is a kind of special lifting and transportation equipment which is specially used for container handling and loading in port.At present,in the design process of quayside crane,the wind load of crane is mainly determined according to GB/T3811-2008 "crane design code".With the development of science and technology,quayside crane is developing in the direction of large-scale,professional,intelligent and light flexible.Although the traditional design method can meet the requirements of crane safety under most wind load conditions,it is difficult to meet the practical needs of quayside crane design because of the large safety factor of wind load and the influence of wind-induced vibration on wind-sensitive components Please.Therefore,to explore the rationality of wind load safety factor and reduce the wind-induced vibration of wind-sensitive components become the urgent problems to be solved.Based on the theory of computational fluid dynamics,finite element analysis and one-way fluid structure coupling,this paper takes a 65 t quayside crane as the research object,and analyzes the average wind load characteristic coefficient of each part and the whole of quayside crane by using numerical simulation method,as well as the impact load of rain load on quayside crane.Through experiments and numerical simulation,the mechanism of wind-induced rod vibration is studied,and the effectiveness of different measures to suppress the vortex induced vibration of rod is explored.The main contents of this paper are as follows :(1)The finite element model of quayside crane is established.By selecting the appropriate turbulence model,the flow field of quayside crane in pure wind environment is numerically simulated.The average wind load shape coefficient of quayside crane under different working conditions is obtained.The value is about 1.4in working condition and 1.34 in non working condition.Based on the one-way fluid structure coupling theory,the displacement of quayside crane in downwind direction under different wind speed and wind direction angle is obtained.When the wind speed is constant,the wind direction angle is 90°.When the wind direction angle is fixed,the maximum displacement along the wind direction of the crane under different working conditions is proportional to the square of the wind speed;(2)According to the rainfall intensity,the volume fraction,falling velocity and rainfall load of raindrops with different diameters are analyzed.Through the numerical simulation of wind and rain flow field,the movement track of raindrops around the quayside crane is obtained,and the number and diameter distribution of raindrops impacting on the quayside crane are counted.Under the condition of 200 mm rainfall and 20 m/s wind speed,the rain load on the quayside crane is only 2.68%of the wind load;(3)The vortex generation process and flow law in the wake region of a cylindrical bar were observed by the flow trace test of the flow field around the bar,and the generation and action mechanism of vortex induced vibration were analyzed.The acceleration signal of the cross wind direction of the bar is monitored,and the acceleration time history curve is analyzed to explore the influence of different disturbing devices on the vortex induced vibration frequency.Through the numerical simulation,the influence factors of vortex induced vibration frequency are further analyzed.It is found that adding guide plate and strip spoiler can effectively reduce the influence of vortex induced vibration on tie rod. |
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