Using the length of the curve line as the quasi-time variable,based on Kirchhoff s analogue technique,the mechanical structural model of DNA elastic rod is established.

Solving two problems of the longitudinal vibration of an elastic rod by Laplace transform;

Solving the vibration problem of elastic rod with concentrated mass on one end by Laplace transformation;

Vibration of an elastic rod connected to a particle;

The Dynamic Modeling and Stability Analysis of an Elastic Link;

The mechanical properties of the rigid and elastic link driving patterns are compared.

Regarding Terfenol-D rod as a viscoelastic rod continuous system and treating the induced strain by external magnetic field as equivalent force,a one-dimension wave equation for the actuator is built.

The differential equation of motion for a viscoelastic rod with point elastic supports under the action of axially periodic load is derived by Lagrange′s equation.

It is difficulty to solve the problem of gracile shaft when the ratio is more than 25 that shaft’s length divide by diameter,by using reverse cutting,clamp &withstand device and mushroom head pin to add rigidity and decrease transfiguration of flexible cutter pole,successfully machining long lead screw when the ratio is 54 that it’s length divide by diameter,then achieve the demand on the drawing.