The ratio of the volume of the air chamber to the additional air chamber, the shape, material, and size of the air spring, and the size of the orifice between the air chamber and the additional air chamber will have a corresponding effect on the system stiffness and natural frequency.

1. The influence of the stiffness of the spring bellow rubber material on the first-order resonance frequency of the system. The experiment shows that the stiffness of the rubber airbag material itself has a great influence on the stiffness of the air spring, which is also the reason for the large difference between the theoretical and experimental values of the air spring stiffness. The greater the stiffness of the rubber air bag material, the greater the stiffness of the air spring, and the higher the first-order resonance frequency, which improves the minimum operating frequency of the system. Therefore, the rubber air bag isolation system should reduce the material stiffness and reduce the natural vibration frequency, so that the minimum operating frequency of the system is as low as possible under the condition that the carrying capacity of the air spring vibration isolator leaves enough margin.

2. When the shaking table vibrates horizontally, the stiffness of the spring sac rubber material is much larger. The body structure of the rubber air spring is soft, so it has the comprehensive isolation effect of axial, transverse and rotating. When the mechanical shaking table vibrates horizontally, the stiffness of the rubber material of the spring bag is much larger.

3. A throttle hole is set between the air spring and the additional air chamber, when the air flows through the throttle hole, because of the resistance and absorb a small part of the vibration energy, and then play the role of vibration damping. In addition to affecting the stiffness and natural frequency of the system, the size of the throttle hole mainly affects the damping of the system.

The stiffness of the system decreases with the increase of the throttle hole opening, and the damping increases first and then decreases with the increase of the throttle hole. The increase of the additional air chamber volume can reduce the system stiffness and increase the damping ratio, and the increase of the excitation frequency will increase the system stiffness and decrease the system damping ratio.