m]}+(]1x}+[k1x}=[m](F( 设{x0)2=∑x)D(o 代入运动方程,得 m∑{X)b,()+E∑{xD()+区k]∑{xD()=-[m1() 方程两端左乘{Xy XH[mk∑{xB()+{Xc∑{X,D(r)+ +KiIR), D())=r, mkg(t) {X[m]{X}D()+{Xxy[elx,D()+{xy[k]x}D() Xy[m]{2(t)设     = = N i i i x t X D t 1 ( ) ( )  (   ( ))     ( )  (   ( ))    ( ) 1 1 1 m X D t c X D t k X D t m I x t g N i i i N i i i N i i i    +   +  = − = = =                (   ( ))      ( ) ( ( )) ( ( )) 1 1 1 X k X D t X m I x t X m X D t X c X D t g T j N i i i T j N i i i T j N i i i T j    + = − + +    = = =                     ( ) ( ) ( ) ( ) X m I x t X m X D t X c X D t X k X D t g T j j j T j j j T j j j T j    = − + + = 代入运动方程，得 方程两端左乘   T X j mx cx kx mIx (t) g  +  + = − 