Experimental Study On Dynamic Characteristics Of Diamond Saw Blades For Noise And Vibration Reduction And Micro-Failure Mechanism

Concrete Cutting process consists of cycle dynamic load, heat stress, fluid dynamics and heat conduction, thus produces strong vibration and deafening noise, and greatly weakens saw blade life and sawing quality. In this paper, dry cutting concrete experiment on diamond saw which is designed by our workgroup and optimized with finite element analysis,and study of typical blade's micro-failure mechanism are carried on.By Real-time dynamic measurement of multi-holes structure sawblades dry cutting three types concrete, the characteristics of cutting force, acoustic emission, noise, and vibration signal were studied and compared with conventional structure saw blade. The results show that AE waveforms is similar to the cutting force waveform, particularly to the vertical cutting force (the main cutting force). Vibration signal waveform is similar to noise signal waveform, which explains that saw-base resonance is the main noise source in sawing process; the distribution of vibration and noise signals in frequency domain is relative to blade rotation speed. With the rotation speed increasing, the distribution of vibration and noise signals in frequency domain is more dispersed. The integrated performance of multi-holes structure saw blade is better than conventional blade. The noise reduction of multi-holes saw blade is notable, which blade B3 is best, B2 follows, then B1 worst. High-speed (26m/s). middle feed speed (600mm/min) and large cut deep (30mm) are most suitable for blade B3,sawing concrete C30. The most suitable cutting condition of blade B2 is high-speed (26m/s), middle feed speed (600mm/min) and normal cut deep (20mm) during sawing concrete C35.By Real-time dynamic measurement of composite structure saw blades dry cutting three types concrete, the characteristics of cutting force, acoustic emission, noise, and vibration signal were studied and compared with conventional structure saw blade. The results show that the integrated performance of composite structure saw blade is better than conventional blade. Composite structure saw blade is not only able to effectively reduce sawing noise, but to improve vibration of cutting process, which blade B8 is best, B9 follows, then B7 worst. Cutting condition of middle-speed (16m/s), middle feed speed (600mm/min) and large cut deep (30mm) is recommended to blade B7 sawing concrete C30. The appropriate cutting condition of blade B8 is high-speed (26m/s), large feed speed (700mm/min) and large cut deep (30mm) in sawing concrete C25. Cutting condition of high-speed (26m/s), low feed speed (400mm/min) and low cut deep (10mm) is becoming to blade B9 sawing concrete C35.The typical failure diamond saw blades surface were observed by means of scanning electronic microscope and zoom stereo microscope, then microstructure failure mechanism of sawblade was analyzed. The results show the main failure form of sawblade is the slot bottom crack. The initial crack patulous direction is vertical to fracture entrance surface, with the continued expansion cracks direction vertical with the main cutting force. There are two types of cracks shape, wave-shaped and straight. The microstructure of sawblade along radial direction is vastly different. After nitriding, saw tooth structure is large different to the core. For cutting temperature reaching about 300℃, process of sawing stone is equivalent to low-temperature annealed to saw blade, the small particles of carbon and nitrogen compounds absorb energy and grows up; Moreover, due to temperature gradient distribution is along with saw radial, the closer to saw tooth the more obvious change of tissue, while saw blade center still retains the original structure.