Estimation of Bulk Density Distribution in Powder Compact with Acoustic Emission

Research Project

Project/Area Number	60550673
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	化学工学
Research Institution	Doshisha University
Principal Investigator	MIWA Shigeo Doshisha University, 工学部, 教授 (40066105)
Co-Investigator(Kenkyū-buntansha)	HIDAKA Jusuke Doshisha University, 工学部, 助教授 (80104602)
Project Period (FY)	1985 – 1986
Project Status	Completed (Fiscal Year 1986)
Budget Amount *help	¥2,000,000 (Direct Cost: ¥2,000,000) Fiscal Year 1986: ¥500,000 (Direct Cost: ¥500,000) Fiscal Year 1985: ¥1,500,000 (Direct Cost: ¥1,500,000)
Keywords	AE count rate / AE cumulative count / Acoustic emission / Powder compact / Shear flow / 剪断崩壊音
Research Abstract	The generating mechanism of sound in shear flow of a granular materials is discussed by applying powder mechanics and acoustic theory. The stress -strain relation in the deformation and flow of granular materials is generally discontinuous. The discontinuous behaviour is one of the fundamental properties of granular materials. In the shear flow, rupture layers are formed periodically in the granular bed. The sound field generated by the formation of rupture layers is estimated on the basis of the model of sound radiation from a piston in an infinite wall. The sound pressure waveform agrees well with the measured one. These results show that the sound parameters closely relate to the formation of rupture layers, and show the feasibility of the instantaneous measurement of bulk density distribution in powder compact by using acoustic emission. Acoustic emission from powder bed is observed during compaction, to obtain the relationship between the parameters of AE and the shear flow in powder compact. The stress-strain relation in powder compaction can be obtained by the measurement of AE cumulative counts, and the correlation is observed between AE count rate and the periodicity of shear flow in powder compaction.