絶縁用封止材として使われるエポキシ樹脂硬化反応の解析第2報 エポキシ樹脂の粘弾性構成則と界面完全接着モデルによる応力―ひずみ解析
Analysis of Curing Reaction for Epoxy Resin Used for Electrical InsulatorsPart II Stress-Strain Analysis with a Viscoelastic Constitutive Relationship for Epoxy Resin Using a Full Adhesion Interface Model
福永守高・山田敏郎・蒲生正浩・加納重義
Fukunaga, Moritaka / Yamada, Toshiro / Gamou, Masahiro / Kanoh, Shigeyoshi
A kinetic analysis of the curing reaction between an epoxide (Epikote 828) and a carbonic acid anhydride (HN-2200) using a finite element analysis with a coupled matrix has been previously reported. Shrinkage of the epoxy resin during the cure creates an internal stress. Both the reaction rate and the material constitutive relationships have great influence on the internal stress. Although stress relaxation reduces the internal stress, it has not been taken into account in the previous work. In order to introduce the effects of stress relaxation of the epoxy resin in the finite element analysis, the relaxation modulus was obtained from complex modulus measurements made on a dynamic mechanical analyzer. The relaxation modulus was expressed as a Prony series. The influence of stress relaxation on reducing the internal stress of the epoxy resin was estimated with this relaxation modulus. The Maximum equivalent stress after stress relaxation was one-fiftieth that without the stress relaxation. Experimental results showed good agreement with those of numerical analysis without mean normal stress relaxation when the epoxy resin was put between metal parts. This indicated that the mean normal stress relaxation of epoxy resin is negligible.
Key words: Epoxy resin / Viscoelasticity / Dynamic viscoelasticity / Prony series / Finite element analysis