variational principle的用法和样例：
例句
- Variational principles play an important role in the formulation of many problems of mathematical physics.
变分原理现在许多数学物理的表述中起着重要作用。 - In this paper the elastic and elastoplastic interal forces of Cable dome strueture are analysed by the energy Variational principle.
本文采用能量变分原理分析拉索穹顶结构的弹性和弹塑性内力。
