異材界面における接触熱抵抗の評価

摘要

When jointed portions of structures and machines are subjected to thermal loads, various problems and troubles occur due to the difference in thermal expansion between mating parts. In order to accurately analyze thermal and mechanical behaviors of the joints, the effect of thermal contact resistance must be taken into account. In this paper, thermal contact coefficient, which is the reciprocal of thermal contact resistance, at the interface composed of dissimilar materials is quantitatively measured by infrared thermography. The target materials are common engineering materials such as carbon steel, stainless steel and aluminum alloy. It has been shown that there exits a significant direction effect in thermal contact coefficients when the mating surface is composed of different materials. That is, the magnitude of the coefficient gives larger value when the heat flows from the material with lower thermal conductivity to the one with higher thermal conductivity. Also, the effects of contact pressure and surface roughness are evaluated. An empirical equation to estimate thermal contact coefficient is proposed, which can approximate the experimental values with sufficient accuracy from the engineering point of view.%一般に機械構造物は多数の部品から構成されており，rn熱負荷を受けた場合の熱および力学挙動を高い精度でrn解析するためには，界面における“接触熱抵抗”の影響rnを考慮しなければならない．接触熱抵抗は接触面面圧rnによって大きく変化し，界面を構成する材料の熱伝導rn率，表面あらさや硬度にも大きく影響される．前報rnでは，代表的な工業材料である炭素鋼，ステンレス鋼，rnアルミニウム合金等を対象として，同種材料で構成さrnれる界面における“接触熱伝達率”について，接触面rn面圧，表面あらさ，材料の熱伝導率とピッカース硬度rnの影響を考慮した評価式を提案した．