Research On Local Stability Of Telescopic Boom

Truck crane is one of the main tool carring out materials handling. The telescopic boom of truck crane have some characters. First, its structure is complex. Second, its work conditions are many. Third, its local effect is important. Because telescopic boom's plates are typical thin-metal shells, so the local stability is a main aspect of boom's structural design. We usually calculate telescopic boom's local stability according to criterion. The calculating model based on simply supported rectangular plate. But the plate is not simply supported rectangular plate actually, So a factor is introduced in criterion to modify calculating result. However, the contacts between Slip-Blocks and plates could affect calculating result of telescopic boom's local stability. And this kind of affection could not be modified through a factor in criterion. In order to calculate telescopic boom's local stability more accurately, it is valuable to research on it furthermore.With the development of computer technology, finite element analysis has been widely used in engineering. Finite element analysis could achieve structure's static analysis, eigen buckling analysis, modal analysis, spectrum analysis etc. The analysis to buckling character through finite element method could obtain the more accurate results. Because the interaction during telescopic boom's plates and more accurate loads and constraints could be introduced in calculation through the finite element method. So the utilization rate of telescopic boom's material and telescopic boom's design quality could be improved.The aim of this subject is to find out how much the contacts between Slip-Blocks and plates influence telescopic boom's local stability. By studying the structure and loads of truck crane's rectangular section telescopic boom and hexagon telescopic boom, this paper calculates and analyses the local stability of them under different load case through the finite element method and analytic method introduced in criterion. The phenomenon indicated by analysis results is as follow. The local stability could enhance along with contact width of Slip-Blocks increase. To the rectangular section telescopic boom, the local stability could increase by 70%. To the hexagon telescopic boom, the local stability could increase by 40%. If this kind of contact is not introduced into the finite element method, the finite element analytic result is approximatively equal to the analytic calculating result. The analytic method given also could research on the local stability of the other kinds of telescopic booms.