Vibration Noise Study On Diamond Circular Saw Blades With Round Noise Reduction Holes

Diamond circular saw blades have a wide range of applications in cutting granite, marble, crystal, glass, concrete and other materials. But sawing by diamond circular saw blades produces great noise,whose sound power level attains to 110dB and even more. On the saw blade open hole can effectively reduce noise radiation noise, and has been widely used, but the present research is far lagging behind the production requirements, so its study has important theoretical and practical significance.Finite element and boundary element method combined with indirect simulation method to study diamond saw blade special acoustic radiation, and orthogonal noise simulation of open hole effect on the acoustic radiation characteristics of diamond saw. First, finite element model of the diamond saw blade was established. the natural frequency of vibration mode of diamond saw blades was achieved through Lanczos method. Then we calculated the dynamic response of the diamond saw blade under the condition of transverse excitation through modal superposition method. Finally the speed of the diamond saw blade was used as the boundary condition of the acoustic IBEM model to calculate its radiated noise. Results showed that the axial modal of the diamond saw blade was easy to excite and that diamond saw blades were good sound emitters.The acoustic radiation power of diamond saw blade could be more than 110 dB. The pure nodal circular mode shape and multi-nodal circular and less-nodal diameter mode shape of diamond circular saw blades majored in aoustic radiation. The sound radiated power decreased as the nodal diameter increased under certain nodal circular. The radiated sound field distribution of the diamond saw blade possesses symmetry as its structure is axisymmetric. The radiated sound field of pure nodal circular mode shape distributed as evenly semicircular. Nodal circular mainly affected the sound power level while nodal diameter mainly affected the directivity of sound field.noise reduction holes reduced noise in broad band. Noise reduction holes did not necessarily reduce sound radiated power of diamond circular saw blades. Inappropriate noise reduction holes could even increase sound radiated power of diamond circular saw blades. Factors of noise reduction holes on sound radiated power of diamond circular saw blades were:distance between holes and the center; the size of holes;numbers of holes(ranking successively). Noise reduction holes in the corresponding major deformation zone had an good effort on sound radiated power caused by pure nodal circular,while no influence on directivity of sound field.As to multi-nodal circular and less-nodal diameter mode shape, noise reduction holes had a better effort in outer deformation zone and proper size. Noise reduction holes changed the directivity of sound field while made it seem more uniform on the whole.The numerical simulation calculation provides certain reference for taking measures to devise diamond circular saw blades and to deduce circular saw blades noise.It also established the foundation of noise reseach on combined saw and the sandwich saw.