(中南工業(yè)大學(xué)力學(xué)開放實驗室， 長沙 410083瑞典皇家工學(xué)院固體力學(xué)系， 斯德哥爾摩 10044， 瑞典
)
摘 要: 滾珠軸承接觸點附近的高壓剪應(yīng)力是引起軸承疲勞破壞的原因。 為獲得高強度鋼在壓剪疲勞加載下的斷裂性態(tài)， 通過軸向裂紋薄壁圓筒的壓剪疲勞加載試驗， 研究了這類材料的疲勞破壞規(guī)律。 結(jié)果表明， 復(fù)合疲勞加載時門檻值對壓應(yīng)力分量并不敏感， 但對擴散速率和臨界擴展角卻有明顯影響。 裂紋擴展速率隨壓應(yīng)力增加而提高， 裂紋較快達到失穩(wěn)； 裂紋擴散角則隨壓應(yīng)力增加而減小， 疲勞裂紋將向有利于Ⅰ型斷裂的方向擴展。 這表明軸承滾道內(nèi)， 任何平行于壓應(yīng)力的缺陷、 微裂紋都將是十分危險的。
關(guān)鍵字: 疲勞斷裂 門檻值 應(yīng)力強度因子 裂紋擴展速率
HIGH STRENGTH STEEL SUBJECTED TO
COMPRESSIVE SHEAR LOADING
（Opening Laboratory of Mechanics, Central South University of Technology, Changsha 410083, P. R. China
Department of Solid Mechanics, The Royal Institute of Technology, Stockholm 10044, Sweden
）
Abstract:High compressive-shear stress beneath the contact point of ball bearing is the main reason for its fatigue failure. In order to obtain the knowledge of compressive-shear fatigue crack growth, thin-wall tube specimens with axial crack are used in the experiments. The specimens are loaded by a cyclic torque combined with different axial compressive stresses. The results show that fatigue crack growth rate and cracking angle are greatly affected by compressive stresses, the crack growth rate increases while cracking angle decreases with the increasing of compressive stresses. The threshold value seems insensative to compressive stresses. The results also show that fatigue crack growth tends to mode Ⅰ fracture and become unstable at higher compressive stresses, which reveals that any microcracks or faults parallel to compressive stress are the most dangerous under fatigue loading.
Key words: fatigue fracture threshold value stress intensity factor crack growth rate
