Study On Overturning Stability Of Truck Cranes In Restricted Space

Truck cranes have a very important position in the field of construction machinery due to their good mobility and large working range.They are widely used in construction sites,factories,ports,mines,stations and hydropower stations.As truck cranes are more and more widely used in various venues,their lifting environment is becoming more and more complicated.In order to reduce the input of foundations or the limitations of the original environment in many sites of lifting operations,the crane legs cannot fully support.Therefore,the telescopic support of the outrigger needs to be maximized according to the specific site.Under such conditions,if the lifting weight determined by the overturning stability cannot be provided,the torque limiter cannot be safely protected.In this way,not only can the performance of the crane not be fully utilized,but it is also more likely to cause overturning accidents,leading to irreparable economic losses.However,at present,there are few studies on the overturning stability of the domestic crane for the situation where the outriggers extend arbitrarily in a restricted space.Therefore,it is very necessary to study the overturning stability of truck cranes in restricted space.In this paper,the truck crane is taken as the research object.By comparing the overturning stability of the truck crane based on the torque method and the ZMP method in a restricted space,the moment method is used to achieve the lifting weight determined by the overturning stability of the whole machine.The force method is used to deduce the calculation formula of the reaction force of the supporting outrigger and its influence on the lifting performance based on the overturning stability.Based on the geometric nonlinearity,the influence of the deformation of the boom on the overturning stability was analyzed using the space beam element finite element method.In this paper,first of all,based on the assumption of the rigidity of the truck crane,the truck crane model is parameterized,and the currently used methods for judging the stability of the crane overturning stability are analyzed.And it is determined that the moment method is used to calculate the lifting capacity of the truck crane in the restricted space overturning stability,and the rapid and accurate calculation of the lifting capacity in the restricted space is obtained.Then,using the force method of structural mechanics,the calculation formula of the support reaction force of the legs of the truck crane is deduced,and the calculation formula of the reaction force of each support leg of the truck crane under arbitrary loading in a restricted space is obtained.The research on the determination of the supporting form of the craneduring the hoisting process was carried out to ensure that the calculation result of the outrigger reaction force is in accordance with the actual situation.The limit of the maximum allowable pressure of the outrigger to the lifting weight calculated based on the torque method is studied according to the calculation formula of the outrigger reaction force.Taking QY25 truck crane as an example,ANSYS was used to perform finite element analysis on the outrigger reaction force to verify the correctness of the force method to calculate the outrigger reaction force calculation formula.In addition,the geometric nonlinear deformation of the boom is analyzed using the spatial beam system element to study the influence of the nonlinear deformation of the boom on the overturning stability during loading.Based on the above analysis,the research conducted in this paper provides a guarantee for the safety of hoisting operations such as truck cranes with outrigger operations in restricted spaces.It also ensures the full use of the operating site,maximizes the crane’s operating capacity,and effectively reduces overturning accidents caused by operational errors.It also provides an important theoretical reference for the calculation and analysis of its anti-overturning stability,and provides ideas for the research on the anti-overturning stability of mobile construction machinery and mechanical structures with four-point support.