An Universal Dynamic Equation for Unrestrained Body Derived by Using Variation Method

An universal dynamic equation for unrestrained body has been derived in the form of tensor by using variation method.As a particular example, dynamic equation both for rigid body and for elastic deformation body can be obtained directly from the universal dynamic equation. Also, the analysis of the movement of deformation body and the dynamic problem of the mixed system, which composed by rigid body and elastic body, are to be resolved by using this universal equation.