New estimation method for formability of stampable sheet part by frequency analysis of AE

1997 Fiscal Year Final Research Report Summary

• Project/Area Number: 07650143
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 機械工作・生産工学
• Research Institution: Osaka University
• Principal Investigator: FUJIWARA Junsuke Faculty of Engineering, Osaka University, Associate Professor, 工学部, 助教授 (60116093)
• Co-Investigator(Kenkyū-buntansha): HANASAKI Shinsaku Faculty of Engineering, Osaka Univ., Professor, 工学部, 教授 (50029097)
• Project Period (FY): 1995 – 1997
• Keywords: Stampable sheet / Heating flow molding / Molding processing / AE / Formability / Frequency analysis

Research Abstract

In bending fracture of Polypropylene stampable sheet, it is possible to recognize the difference of fracture mechanism by frequency analysis of AE wave. In bending fracture of PET stampablie sheets which have different coupling agents of glass fibers, the difference of the interface bonding was investigated by this new method. Moreover, in order to investigate the effectiveness of this method, other composites, that is to say, unidirectional reinforced molded parts with Polyallelate fiber (AF), Aramid fiber (KF), Glass fiber (GF), and Carbon fiber (CF) were examined. The main results obtained are as follows : (1) The mouled part whose coupling agent was the binder for epoxy resin showed good interface bonding, and there was little interface debonding. (2) The molded parts whose coupling agent was the binder for unsaturated polyester and polypropylene, showed a lot of interface debonding. (3) The bending strength of CFRP was highest and GFRP was also rather high. The bending strength of KFRP was half of CFRP and GERP.The bending strength of AFRP was lowest. The elastic modulus of CFRP was highest. The elastic modulus of AFRP was lowest. As compared with the elastic modulus of Epoxy resin, these composites had high elastic modulus. (4) As AFRP and KFRP were reinforced with ductile fracture fibers, the cross section became small because of necking in the middle of the bending fracture. Before the maximum load, the gradient of the load-displacement curve became gentle because of the interface debonding. (5) As CFRP and GFRP were reinforced with brittle fracture fibers, the compressive fracture occurred in the vicinity of the maximum load and the fracture became active.