Isolators, Rigid Body, Low Frequency
Nowadays, the customers of refrigerators and freezers have become more exigent in respect to the acoustic comfort of these home appliances. Among the noise sources, there are the refrigerant flow, the fans and the compressors. The compressors might be responsible for a part of the cabinet low frequency noise which could be generated either by the gas pulsation that excites the tubing or the compressor low frequency vibration that transfers energy to the cabinet base plate and tubing. The compressor low frequency vibration is a function of the mechanism loads and the gas pressure that acts on the piston and it is modulated by its running frequency and harmonics. Besides, at low frequencies, the compressor behaves as a rigid body assembled on isolators or grommets which link the compressor to the cabinet base plate. If one knows these rigid body natural frequencies, itâ€™s possible to optimize the refrigerator project, providing a better acoustic performance for manufacturers and final customers. Based on this context, this paper aims to present a study of the compressor grommets, usually made in rubber. First of all, an investigation about the materials is carried out using a technique with a single degree-of-freedom system. In a second time, an analysis of the static behavior of an isolator using the rubber properties is done. Finally, a numerical model to predict the modal behavior of a compressor assembled on a rigid base is created and validated experimentally.