In air conditioner piping vibration, the rubber grommets placed below the compressor are deflected in the same situation and acts to isolate vibration.
Typically, there are two types of stiffnesses—static and dynamic stiffnesses. The determination of the static and dynamic stiffness characteristics becomes critical to the function of the product. Generally, the dynamic stiffness is higher than the static stiffness. As vibration is a dynamic phenomenon and normally involves relatively large dis- placement, the rubber isolation especially highly damped isolator is dependent upon the behaviour of the rubber grommet under dynamic operating condition [7]. Since rubber isolator has rate dependent stiffness property [8], it is appropriate to characterize the property at the actual dy- namic condition in order to predict the system vibration characteristics. The rubber grommets used in the analyzed outdoor unit are EPT rubber and the information of stiffness is not provided by the supplier. Hence the static and dy- namic load-deflection tests are conducted to identify the static and dynamic stiffnesses of the rubber.