Tianhe Telescopic Mast Wind Force Analysis
Wind Resistance – Mast Wind Resistance and Calculation Method  
1) Knowledge of Mast Wind Resistance Mast wind resistance is one of the important technical indicators of mast products. Every customer wants to know how much wind force that their mast can withstand after installing loads; however, hardly anyone can answer this question accurately.This is because mast’s wind resistance performance is determined by the following three factors: A Mast structure and material B Use height of mast C Weight, volume and shape of loads In case that the above three conditions are provided, we can use the following three methods to calculate specific wind resistance index: （1） Theoretical calculation: Use finite element analysis and other methods. （2）Simulation experiment: Convert different scales of wind power into wind pressure, and then use physical method (tensiometer) for testing. （3） Wind tunnel experiment: Place the mast and loads in the wind tunnel, and simulate wind speed for testing. In the above three methods, the third method can provide a more realistic value. However, the cost and condition requirements for wind tunnel experiment are very high. For example, is there a big enough wind tunnel for experiment of an 18meterhigh mast with loads? Is the experiment possible ? How much will it cost? These are all problems. Therefore, for mast manufacturers, wind resistance index of mast can only be provided using the first two methods
2）Calculation Method of Mast Wind Resistance 

1.1、Designed benchmark wind speed of lifting rod ▽=100km/h≈28m/s 1.2、When ▽= 28m/s, estimate wind resistance D borne by the lifting rod. 1.3、The lifting rod has a total of 4 segments. Specific size is shown in the table. 





2.Wind Resistance Calculation 

w=πd²／32 ﹛1﹙d_{o}/d ﹚^{4}﹜=3.14×202²/32 ﹛1－﹙190/202 ﹚^{4}﹜=181332mm² 

2.2 Gust wind coefficient
The socalled gust Kg is the ratio of maximum instantaneous wind speed V2 and mean wind speed V2 within observation time. It is related to observation time, average wind speed, topography, surface roughness, recurrence interval of benchmark wind speed, and other factors. Generally, Kg is between 1.2 and 1.5, here Kg=1.3.
2.3 Reynolds Number of Lifting Rod in Different Diameter Segments
It can be seen from the curve that the Re range of the lifting rod is just within the area of CD=1.2. =1.2×２/20×36.4²×0.202×1.7×1.3² =57.67kg
2.5 Strength Check
6063T6下σ=205Mpa，To ensure safety, takeσ=160Mpa
