- 著者
- 川原 啓史 野田 尚昭 吉村 慎平 大田 健人
- 出版者
- 一般社団法人 日本機械学会
- 雑誌
- M&M材料力学カンファレンス 2008 (ISSN:24242845)
- 巻号頁・発行日
- pp._OS1422-1_-_OS1422-2_, 2008-09-16 (Released:2017-06-19)
自動車用ブレーキホースのかしめ構造の決定は,従来,試作品を実験で評価して行われているが,本研究では,耐久信頼性向上,開発効率向上のため,FEMで定量的に解析する手法を検討した.本稿では,ホースを構成するゴムにへたり(圧縮永久歪)が生じた場合の液漏れに影響するシール性能を考察し,これを基にホースの使用環境温度の違いによるホースの寿命推定を行った.これらの事から,ホースを構成するゴムにへたり(圧縮永久歪)が生じると,シール性能に大きな悪影響を及ぼすことを示した.さらに,寿命推定では,使用環境温度が高くなればなるほど寿命は短くなるということを示唆することができた.
- 著者
- ケビンサニー 岡﨑 三郎 髙桑 脩 松永 久生 船越 裕亮 沖田 耕一
- 出版者
- 一般社団法人 日本機械学会
- 雑誌
- M&M材料力学カンファレンス 2019 (ISSN:24242845)
- 巻号頁・発行日
- pp.OS0319, 2019 (Released:2020-05-25)
Tension-compression fatigue tests were conducted on non-charged and hydrogen-charged additively manufactured Ni-based superalloy 718 to investigate the effect of solute hydrogen on the fatigue strength properties of the material. The surface condition of the specimens was either as-built or mechanically-polished, aiming to clarify the effect of process-induced defects and roughness on the property. Fractographic observations using a scanning electron microscope manifested that process-induced defects existed at the fracture origin of as-built specimens, whereas such defects were not observed in the mechanically-polished specimens. However, both the fatigue life and the fatigue limit of the specimens were neither affected by surface condition nor by hydrogen. The results revealed that (1) the defects were not detrimental to the fatigue strength of the material due to its large defect-size tolerance accounted to its coarse-grained microstructure, based on comparison with previous studies conducted on forged Alloy 718, and (2) hydrogen caused no remarkable influence on both crack growth rate and crack growth threshold of the material.
- 著者
- 井上 貫太郎 鯨井 翔 志澤 一之
- 出版者
- 一般社団法人 日本機械学会
- 雑誌
- M&M材料力学カンファレンス 2016 (ISSN:24242845)
- 巻号頁・発行日
- pp.OS01-15, 2016 (Released:2017-06-19)
In this study, we carry out dynamic recrystallization (DRX) analysis for Mg/LPSO alloys based on dislocation-based-crystal plasticity and multi-phase-field (MPF) models considering change in environmental temperature to reproduce temperature dependence of the strengthening mechanism: the kink deformation of LPSO phase and the grain refinement of α-Mg phase in the vicinity of LPSO phase due to DRX. We introduce some thermal effects into the critical resolved shear stress (CRSS) and the dislocation mobility in dislocation-based crystal plasticity model, and into the nucleation condition in MPF model. The results obtained here show that the grain refinement and work hardening occur depending on environmental temperature through the interaction between deformation and recrystallization.