箱梁歪扭(畸变)微分方程,以剪切角γ(z)为未知量,采用板梁框架法进行了推导,公式的导演较为繁冗。本文以歪扭(畸变)挠度W为未知量,用闭口薄壁杆件理论与能量法进行推导,然后换算成γ(z)的微分方程。物理概念清楚,推导过程简明,最后求解W,并利用斯坦利(Steinle)公式导出歪扭双力矩解析式。 The differential equation of skew (distortion) of box girder is deduced by using the beam-frame method with the shear angle γ (z) as the unknown quantity, and the formula director is more complicated. In this paper, the deflection (distortion) W is taken as an unknown quantity, deduced by the theory and energy method of the closed thin-walled rod, and then converted into a differential equation of γ (z). The physical concept is clear, the derivation process is concise, finally W is solved and the crooked double moment analytic formula is derived using the Steinle’s formula.