箱形伸缩式臂架的二阶弹性分析属几何非线性问题。本文提出了一种在刚度矩阵和荷载列阵的建立方面与传统的有限元法有某些不同的一种方法。该法的优点是单元刚度矩阵和荷载列阵的建立简便;单元数目和计算工作量少;边界条件便于处理等。本文以 QY16起重机的箱形臂架为例进行了计算,计算结果与试验结果比较一致。 Second-Order Elastic Analysis of Box-Type Retractable Booms is a Geometrically Nonlinear Problem. In this paper, we propose a method that is somewhat different from the traditional finite element method in the establishment of stiffness matrix and load array. The advantage of this method is that the establishment of element stiffness matrix and load array is simple; the number of units and computational workload are small; the boundary conditions are easy to handle and so on. In this paper, QY16 crane box arm as an example, the calculation results are consistent with the test results.