关于虚功率原理的注记

A Note on the Principle of Virtual Power

为了简化计算，引入了虚速度、虚功率的概念，并推导出虚功率原理。借助于运动学中的理论，较容易地分析出一些处于平衡状态的系统中力的作用点处的速度之间的关系，从而较容易地列出虚功率方程，进而得到正确的结果。

In order to simplify calculating, concept of virtual velocity and virtual power are led into. The principle of virtual power is discussed.Using theory of kinematics, relations between velocites of point of application of force are ananlysed in system of equilibrium.Thus, equations of virtual power are formulated. Correct result are gained.