From the motion equation of the bar which vibrates one-dimensionally and longitudinally, the model of mechanical four-terminal network and the transfer equations are set up, and the natural frequency equation of coniform horn and the ratio of speed of vibration are derived.

Unified treatment of ultrasonic horn characteristics based on four-end network approach;

Based on the theory of four-end network, the resonant frequency of the composite stepped ultrasonic torsional-mode concentrator with a cone-like transited part, which depends on the geometrical dimensions of the tool rod attached to the concentrator, is studied by using electromechanical analogy method.

Based on the transfer-matrix method,the general expressions of equivalent four-terminal network parameters of varying section torsional horn are derived,the relations between frequency equation and both the rotational velocity amplification and that of the surface tangential velocity of stepped type torsional ultrasonic horn with transitional section of cosine-like type are obtained.

This paper conducts an investigation into machinery vibration isolation by means of mechanical network and fourpole parameters method.

The piezoelectric transducer and the variable amplitude bar are designed by four-terminal network method.

Applying the four-pole network theory in the computing of acoustic performance for vehicle exhaust system,using the method of Matlab and VC hybrid programming,a CAE software for forecasting and analyzing the performance of vehicle exhaust system is designed and realized.