Research On Wind-Induced Response Of Flat Top Tower Crane

With the introduction of a series of policies such as "Made in China 2025".The level of the machinery industry and the entire construction machinery manufacturing industry have been continuously improved.At present,some of our construction machinery enterprises have entered the first camp of the world.As an important part of construction machinery,tower crane has also been developing continuously in recent years.Tower crane has been widely used in engineering construction fields with its advantages of high lifting height,large turning radius,fast working speed and so on.However,in recent years,the global severe weather has increased and typhoons and hurricanes have occurred frequently,the sudden huge wind poses a great threat to the safety of tower cranes.Therefore,it is particularly important to consider the influence of wind load in the structural design of tower crane.At present,engineers often use the theoretical formula in Code for Design of Tower Crane to calculate the static wind load for static analysis.The tower crane designed according to this static wind load is applicable to most regions.However,in some coastal cities that are vulnerable to hurricanes,there are certain security risks because the pulsation of wind is not considered.Therefore,it is very meaningful to simulate the pulsating wind in line with the actual situation and load it onto the tower crane for transient dynamic analysis,which is also the main research content of this paper.The specific tasks and conclusions are as follows:1.This paper takes a certain model of flat head tower crane as the research object.The simplified geometric model of flat-head tower crane is established.According to the geometric model,the beam element is used to build the finite element model of the flat-head tower crane.Using Fluent to construct a numerical wind tunnel model to simulate the wind load on a flat head tower crane and compare it with theoretical calculation values.2.According to the theoretical formula in Code for Design of Tower Crane,the wind load on the flat-head tower crane is calculated.Compare the calculated results with the simulation results of the numerical wind tunnel under the same conditions.The error of the results is less than 10% and the theoretical calculation value is slightly larger.This shows that the theoretical calculation value is biased towards safety.The subsequent static wind load will also be applied using the theoretical calculation value.3.The theoretical wind load value calculated according to the Code for Design of Tower Crane is loaded onto the flat head tower crane with APDL command.After setting the relevant solution parameters,the static calculation is carried out to obtain the displacement of different observation points of the flat head tower crane and the maximum equivalent stress suffered by the tower crane.The maximum equivalent stress value obtained by calculation is 183.1MPa.The stress value is less than the allowable yield stress of 283 MPa.The stress conforms to the strength standard,and the structure tends to be safe.4.Using the harmonic superposition method,the Kaimal spectrum is randomly simulated by MATLAB program,and the time-history curve of fluctuating wind speed is obtained.Then the fluctuating wind speed is converted into fluctuating wind load,which is loaded onto the flat head tower crane in the form of load step through APDL command.Then,after setting a series of solving parameters,the transient dynamic analysis of the flat head tower crane under fluctuating wind load is carried out.By comparing with the corresponding data under static wind load,it is found that the analysis result of transient dynamics is larger.The average relative error of displacement is about 70%,and the maximum equivalent stress of flat head tower crane under fluctuating wind load is 289.6MPa,which has exceeded the allowable yield stress of the structure.Therefore,it is necessary to consider the pulsation of wind in the structural design of flat head tower crane.