Characteristics of resonance sound in a circular saw enclosure

Several studies have been conducted to reduce the idling noise of circular saws because the sound level is extremely high and harms the environment. However, conventional noise suppression technology only controls the vibrations of the circular saw itself, whereas idling noise can be generated when the air inside the enclosure is resonant. In this study, the relationship between the rotational speeds of the circular saw blade and the frequencies of the resonance sound when the circular saw blade is running idle in an enclosure was examined. Additionally, the sound pressure modes and frequencies of the air in the enclosure were analyzed using the finite element method of acoustic analysis. The results showed that resonance sound was generated only when the circular saw blade was enclosed. The frequencies of the resonance sound generated by a circular saw blade made of acrylic plastic were the same as those generated by a steel saw blade. The resonance sound was generated regardless of the outer diameter of the circular saw blade. The peak resonant frequencies formed a step-like line during the analysis in which the rotational speed of the saw blade was steadily increased.