应用该小势能原理的直接法,位移试函数必须满足全部位移边界条件,但在许多实际工程结构中,边界条件是比较复杂的,要寻找一族完全满足位移边界条件的试函数是困难的。若我们将最小势能原理的直接法和加权残数法相结合,将特殊的位移边界条件加权引入能量泛函中,就可克服这一困难 Applying the direct method of the principle of small potential energy, the displacement trial function must satisfy all displacement boundary conditions, but in many practical engineering structures, the boundary conditions are more complex. It is difficult to find a family of trial functions that fully satisfy the boundary conditions of the displacement. If we combine the direct method of the principle of minimum potential energy with the method of weighted residuals, we can overcome this difficulty by introducing special displacement boundary conditions into the energy functional.