起重机吊臂通常制成变截面的形式,由于起升绳和变幅绳拉力的影响使轴向压力的方向在吊臂旁弯过程中发生变化,因而使吊臂计算比普通压弯构件复杂。本文对吊臂计算很关重要的弯矩和挠度放大系数,考虑压力方向变化和变截面影响的长度系数,计算吊臂挠度时用的变截面折算惯性矩以及伸缩臂的局部弯曲等 Crane boom is usually made of variable cross-section form, due to the lifting rope and luffing rope tension so that the direction of the axial pressure in the boom side bending process changes, so that the boom is more complex than ordinary compression bending components. In this paper, the moment and deflection magnification factor which are very important in the calculation of boom are taken into account. The length coefficient of variation of pressure direction and the influence of variable section are taken into account. The moment of inertia of variable section and local bending of telescopic boom