Parametric Structural Mechanical Properties Of Flat-head Tower Cranes And Optimization Study

The tower crane is an indispensable piece of machinery for modern construction sites,its main task is to carry out aerial lifting,handling,installation and other operations on the construction site.The tower crane has the advantages of a large lifting capacity and a wide operating range.Its base is fixed to the ground during operation and is more resistant to loads and wind influences,so its stability and safety are even more outstanding.In addition,the tower crane’s lifting boom can be extended to great distances,making it suitable for handling operations on large construction sites.As modern buildings continue to grow taller and taller,there are more and more types of tower cranes,classified by shape,with moving jibs,spikes and flat-head tower cranes.Flat-head tower cranes have developed rapidly in recent years due to the lack of a tower head,which can be cross-used during operations and improves efficiency.This paper takes a flat-head tower crane as the research object,and analyses and studies the types and sections of the tower body,boom and counterbalance jib of the flat-head tower crane.The whole machine is modelled parametrically using structural analysis software.By comparing the operating conditions and loads of the tower crane,several extreme conditions are selected as the analysis conditions for optimising the mechanical properties of the structure.In the structural hydrostatic analysis of the tower,the internal forces on the tower are first analysed to obtain the calculation formulae of strength and stiffness.Stress and deformation of the whole machine as well as the water calm displacement at the centre tower and boom connection are investigated using the FEA software static analysis module.The dynamics module is then used to analyse the multi-order sensitive modes of the tower,and the harmonic response of the tower is analysed according to the inherent frequencies of the multi-order sensitive modes.Key locations such as the end of the lifting arm,the connection between the central tower and the lifting arm and the corresponding nodes at the end of the balancing arm are selected to analyse their vibration characteristics in three dimensional directions.This will provide basic information for structural design,diagnosis of vibration effects during tower operation and optimisation of structural dynamic characteristics,thus improving the operational efficiency and safety of tower cranes.The tower crane is then subjected to a stability buckling analysis by means of the buckling analysis module.Determines the buckling loads and buckling modes of the various parts of the flat-head tower crane and is used to optimise the design of the flat-head tower crane.To ensure that its parts do not buckle and fail when subjected to normal loads.Finally,an improved quantum particle swarm optimisation algorithm is used to optimise the lightweight design of the tower boom.By optimising the combination of the variable section shape and dimensions of the boom,a rapid lightweight design of the boom is achieved and the total mass of the boom is reduced by17.5% after optimisation.The effectiveness of the optimisation scheme is verified through simulation experiments.