Study of the Opening Angle Influence of Y-shaped Guying System on the Buckling Stability of Telescopic Boom Crane

Abstract

The Y-shaped telescopic boom guying system offers remarkable increases in load capacity of all-terrain crane. However, there are very few articles reporting on this special structure. Because the telescopic boom with Y-shaped guying system is a statically indeterminate space structure of quartic, it cannot be solved by an analytical method and there are no complete qualitative analyses of results. On the one hand, the front guyrope has played a positive role because the pull force partially weakens the bending moment and the deformation of boom head and decreases the stress of the bottom cover plate on the telescopic boom. On the other hand, it has played negative effects due to increasing the axial pressure and the stress of the top cover plate on the telescopic boom. The length and opening angle of guying frame balance the load distributions of working process between the revolution plane and luffing plane. In this paper, the all-terrain crane is simplified as a model which includes the telescopic boom, guying frame, front guyrope and back guyrope in this paper. The eigenvalue buckling analysis of finite element method is used to research the influence of Y-shaped opening angle on the crane maximal lift load decided by buckling stability. The research results show that the critical lifting load determined by stability increases first and then decreases with the increment of the opening angle of guying frame. The bigger of the opening angle, the larger of the pulling force component of guyrope in the revolution, and the better stability in this plane. However, the increasing opening angle will decrease the stability in the luffing plane. The optimal range of the opening angle is between 70° and 100°, which can balance the revolution plane stability and the luffing plane stability. This conclusion might be useful for the design of the Y-shaped guying system of cranes.