Stability Analysis for Horizontal Boom with Double Pulling Rods under Non-Conservative Forces

Abstract

The horizontal boom of the tower crane in the rotary plane is a cantilever structure with large flexibility. Its stability analysis belongs to critical load problems under double non-conservative forces. In this paper, the second-order theory is used to establish the deflection differential equation in the rotary plane of the horizontal boom. According to the deformation compatibility conditions and the boundary conditions, the exact expression of the deflection equation and the instability characteristic equation in the rotary plane are obtained. The premise of the stability analysis is to determine the force relationship of the two pulling rods in the horizontal boom with double lifting points, which is a statically indeterminate structure. This paper is aimed at the structural characteristics and the load forms of the general boom. For the calculation of the pulling rod forces in the boom, the general expression is deduced considering the variety of the cross-section, the load and the position of lifting points. A highly efficient method for the stability analysis of the horizontal boom with double pulling rods is provided by the analytic expression of the instability characteristic equation and the internal forces in the statically indeterminate pulling rods.