| The vibration and noise of circular saw has been an important part that pollut the environment. In the past few decades, a lot of investigations were dedicated to these related subjects. A series of technology were grasped that can reduce vibration and noise, including structure improved design, vibration control in the process of cutting, damping circular saw blade etc. The initial purpose of slots and holes was to reduce the compressed thermal stress that is resulted from temperature gradient. Practice shows that slotting and filling materials effective way of reducing vibration and noise. However, because complex mechanical and acoustic problem exist in the progress of vibration of circular saw, the total and systematic researches on vibration and noise of circular saw blade with slots and filling materials have been still rather rare.Up to now, No accurate theory has been used to explain the effect of slot to circular saw blade. It becomes a bottleneck of this type of Saw's innovation. Due to the above reasons, numerical analysis and experimental study have been conducted in this thesis, which stemmed from the mechanism of vibration and noise of circular saw.Through discussing the influence of slot parameters to vibration characteristic of circular saw, optimization method has been provided. The research provides theoretical guidance for relevant blades enterprises. The main work will be concluded as follows:(1) The equation of vibration of circular saw blade without any slot is established in combination with plate kineties theory. Natural frequancy of free vibration on comman circular saw blade are calculated based on MATLAB program. The result compared with FEA. The dynamic characteristic of circular saw blades with radial slots on the outer edge are investigated. The distribution of natural frequency is studied based on small parameter perturbation theory.(2) By taking vibration characteristic circular saw with matrix slots as the research object, which can be divided two categories: radial slots and annular slots. The parameters of slot affecting the performance of saw blade vibration by analyzing were identified which include the location, width, length and number of slots. The effect of slot parameters to natural characteristic is discussed by FEA method. By taking damping loss factor as a vibration damping evaluation, which were calculated based on modal strain energy method.(3) The transient dynamic characteristic of common circular saw and saw blade with filling materials in slots is studied through FEA methods. The vibration response and attenuation history of two circulaw saw are compared. The results of FEA will be verified by hammering experimental.The numbered analog simulation in the progress of cutting on three different circular saw(without any slot, with slots, with filling materials in slots) are conducted by"moving load"technology.The response of circular saw are compared. In order to verify the effectiveness of FEA, cutting experiments are conducted. Through comparing noise power level of different circular saw, mechanism of vibration reduction has been clarified.(4) Based on the charactetistics of propagation in the medium interface of blending wave.Mechanism of vibration and noise reduction on circular saw blades with slots and filling materials was expounded from the view of transmission interruption and dissipation of elastic wave. That study provided new ideas and theoretical basis from the design of circular saw blade.(5) The influence of slot parameters to circular saw's vibration has been discussed. The minimum square sum of vibration velocity of particle on circular saw is taked as the optimization target.Location of slots, length, width, and number of slots, are thought as the design variables. The restriction of the actual blade's limitation of space is the constraint condition. Structural parameters are optimized through data flow analysis based on ANSYS finite element optimization module.The best circular saw that can produce low noise will be obtained.
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