New estimationof moldability of stampable sheet molded part by frequency analysis of AE wave.

1993 Fiscal Year Final Research Report Summary

• Project/Area Number: 04650111
• Research Category: Grant-in-Aid for General Scientific Research (C)
• Allocation Type: Single-year Grants
• Research Field: 機械工作
• Research Institution: Osaka University
• Principal Investigator: FUJIWARA Junsuke Osaka University, Mechanical Engineering, Asso. Professor, 工学部, 助教授 (60116093)
• Co-Investigator(Kenkyū-buntansha): HANASAKI Shinsaku Osaka University, Mechanical Engineering, Professor, 工学部, 教授 (50029097)
• Project Period (FY): 1992 – 1993
• Keywords: Stampable sheet / Heat flow molding / Molding processing / AE / Moldability / Fraquency analysis

Research Abstract

The strength of fiber reinforced plastic is affected by molding conditions and has wide dispersion. New method was developed with AE on order to estimate the moldability of stampable sheet. The stampable sheet used in this study is composed of polypropylene resin and chopped strand glass fiber. The virious stampable sheets, which had four kinds of glass fiber length, four kinds of fiber content and four kinds of fiber dispersion, were prepared. Thespecimens were molded form these molding materials and were investigated in order to clarify the fracture mechanism in detail. An AE sensor was attached on a test piece with wax. The forty AE waves were measured during one bending test. Then, these AE waves were analyzed with FFT, and each power spectrum was calculated. Consequently the characteristic frequency corresponding to the each frcture states were revealed. That is to say, it is considered that the frequency of 85kHz is generated in the fracture of a glass fiber, the frequency of 65kHz is generated in the fracture of martix (PP), the frequency of 105kHz is generated in the pull-out of a glass fiber from the natrix with slip, the frequency of 135kHz is geverated in the pull-out of a glass fiber from a glass fiber bundle and the frequency of 160kHz is generated in the interface debonding of a glass fiber from the matrix. In order to clarify the relation between the fracture and the frequency, micro tensile test in SEM was carried out. It was clear that the frequency around 135kHz was generated in the pull-oout of a glass fiber from a glass fiber bundle and the frequency around 105kHz was generated in the interface debonding of a glass fiber from the matrix.