Anti-bending Ladder Design For YT53 Aerial Fire Truck

Aerial ladder fire truck is a kind of special fire fighting and rescuing vehicle equipped with telescopic ladder,turntable,bucket,quick elevating trolley and fire apparatus,which is widely used in high rise building fire extinguishing,people rescuing,materials transferring and other elevating work.The ladder,as the "U" type open truss form mainly welded by thin walled steel,not only needs to bear the weight of personnel and materials in the working bucket at the top of ladder,but also needs to bear own weight,fire water's reverse force,wind force and ladder's telescopic and rotating inertia force,etc.Its deformation is much large than traditional closed box-type boom because of its smaller stiffness.In order to improve the smoothness of the telescopic process of the ladder and the running of the quickly elevating trolley along the ladder track,the curved anti-bending ladder can be adopted.The anti-bending amount of the ladder used in the design is counteracted with the sagging deformation of the loaded ladder,so that the desired straightness can be achieved.Taking the ladder system of YT53 aerial ladder fire truck as the research object,based on general finite element structural analysis software ANSYS,the parametric finite element model of the ladder is established.In order to avoid the downward bending posture and to make the ladder is approximately straight,the curved anti-bending design is proposed under the maximum angle and elongation working condition.To ensure that each section of the anti-bending ladder can slide relatively smoothly during the telescopic process,a single curvature radius arc curved ladder design is selected.The best radius needs to be obtained through multiple iterations of the static analysis results of the parametric model.The predicted radius has been used by the actual design of anti-bending ladder products,and its correctness has been verified by the actual test.The research of this paper provides a theoretical basis and calculation foundation for anti-bending ladder design of the series of aerial ladder fire truck.