is a measure to reduce vibration propagation by using impedance mismatch between vibration elements. Vibration isolation technology is often used in the vicinity of the vibration source, which limits the vibration energy on the vibration source and does not diffuse to the outside, so as to avoid exciting the vibration of other components. It should also be used near the objects that need protection, to isolate the objects that need low vibration from the vibration environment, so as to avoid the impact of vibration on the objects. The main measures for isolation are to design suitable isolators. The principle of vibration isolation is to design the natural frequency of object and isolator (mainly spring) system much lower than the excitation frequency (at least three times lower); but for high frequency vibration, we should pay attention to the great change (at least three times less) between the characteristic impedance of isolator and that of connecting structure. For this reason, if the isolator is made of steel wire spring
, it should also be padded with mats made of rubber and felt. Damping should also be considered in the design of vibration isolators. Damping measures should be taken when designing vibration isolators for variable speed machines during start-up so as to avoid excessive vibration when passing through resonance frequencies.
is a measure to dissipate vibration energy by means of viscous effect or friction effect. Damping can restrain the resonance of the vibration object and reduce the amplitude of the vibration object in the resonance frequency region. The concrete measures are to increase the damping of the component or to lay damping materials and structures on the component. For example, the vibration-absorbing alloy materials developed in recent years have large internal damping and enough rigidity, which can be used to manufacture low noise mechanical products. In addition, installing dynamic shock absorber on vibration source is also an effective measure to reduce vibration for some vibration sources. For shock vibration, vibration absorption measures can also effectively reduce the vibration response caused by shock excitation. Electronic shock absorber is another type of shock absorber. His vibration absorption principle is different from the above vibration isolation and damping. It uses electronic equipment to produce a vibration with equal amplitude and opposite phase to counteract the original vibration in order to reduce the vibration.