从薄壁构件的弯扭总势能方程出发，应用最小势能原理，得到了开口薄壁构件几何非线性微分方程的一般表达式及其全部边界条件．阐述了边界条件的物理意义，讨论了实际问题中部分边界条件的不严格所引起的不利结果 Starting from the total potential energy equation for bending and torsion of thin-walled members, the general expressions and all boundary conditions of the geometric nonlinear differential equations for open-walled members are obtained by applying the principle of minimum potential energy. The physical meaning of the boundary conditions is described, and the unfavorable results caused by the non-strict boundary conditions in practical problems are discussed.