Abstract: Constant frequency air-conditioners usually vibrate violently on shutdown, leading to excess pipe stress. In this paper, modal analysis is conducted on pipe system in air-conditioner by experiment and simulation. Natural frequency and modal shape are obtained. Structure of pipe system is optimized in order that the natural frequency of pipe system is far different from the natural frequency of the compressor. The results show that the solution reduces pipe stress on shutdown and improves the quality of the product.

Key words: Pipe design, Pipe stress on shutdown, Modal analysis, Finite element simulation