Research On Reliability Design Of Truck Crane Telescopic Boom

Truck cranes are widely used in engineering on account of its good maneuverability and its rapid transfer.The telescopic boom is the main bearing part of the Truck crane.Most of the truck crane accidents are caused by the failure of the telescopic boom structure,and the economic loss caused by its failure is also serious.Therefore,the telescopic boom can be safe and reliable work determines the life of the machine.Due to technical,man-made and environmental factors,the telescopic boom in the process of design,manufacture and use,will lead to the design parameters uncertainty,such as,structural load,size and properties of materials.The design and verification of the telescopic boom structure is mainly based on the crane design specification(GB3811-2008),and the specification does not take into account the uncertainty of these design parameters.Usually,the influence of these uncertainty factors is very small,but for some specific conditions,the telescopic boom structure can't guarantee its safe.Therefore,it is important to analysis the telescopic boom structure reliability,and based on the result,to guide the designing,manufactureing and using.This paper focuses on uncertain variables which have important influence on the structure of telescopic boom,including dynamic lifting coefficient,yield strength of material,rope swing angle,and thickness of plate.In these variables,the yield strength of material and the thickness of palte has been studied for many years,and it has been able to determine its distribution form,belonging to probability variable.While the rest of the variables are affected by the working conditions,the distribution form cannot be determined,and belonging to the interval variable.Combining probability theory with non-probabilistic theory,proposes a new method for probabilistic and non-probabilistic hybrid reliability analysing of telescopic boom,and studies the influence regularity of the uncertain variables to the structure reliability of telescopic boom,the result can guide the design of telescopic boom.The performence function of telescopic boom structure is established by referring to the design specification for crane(GB3811-2008)and existing research results of the hexagonal telescopic boom.In order to find out the weakness of the telescopic boom,establish the Bayesian network model of structure failure based on the failure mechanism of telescopic boom,Combining the reasoning function of Bayesian network,analyzing the failure reason of telescopic boom,and the influence degree of each failure form,provide reference for the design of the telescopic boom.Based on the results of reliability analysis,the existing lifting characteristics are corrected,and the structure parameters of the telescopic boom are optimized by genetic algorithm,under the premise of the lightest weight of the telescopic boom,making it has higher reliability.Taking a QY50-type truck crane as a calculating example,the reliability analysis of the telescopic boom is carried out,and the importance of each failure reason is calculated,the weakness of the telescopic boom is the local stability of the abdominal plate,and the maximum effect on its failure is the plate thickness.In order to guarantee the safety of in-service equipment,analyze the existing working conditions,recommend reasonable lifting characteristics,and optimize the thickness of the plate to provide a reference for the design of the telescopic boom.