刻槽试件的应力状态分析及超声拉伸疲劳极限试验研究（英文）
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摘要
为了研究带裂纹工件在超声载荷下的疲劳性能,采用自行研制的超声振动单向拉伸实验装置,对刻槽20#钢进行了拉伸试验研究。设计了两端方板、中间为指数剖面、单侧边开有缺口的试件,对刻槽试件的应力状态进行了理论分析,得出了刻槽截面的正应力分布公式。通过改变工件的槽深t和曲率ρ,得出疲劳极限随刻槽深度的加深而降低,在某一深度时达到最小值,然后随之上升;疲劳极限随刻槽曲率的减小而下降,在某一曲率值时达到最小值,然后随之上升。该试验证明了疲劳极限不仅与应力集中系数有关,还与刻槽深浅、应力梯度和其他参数有关,具体工作还需要进一步研究。
In order to study the fatigue performance of cracked workpiece under ultrasonic loading,the tensile test of notched 20 steel was carried out by self-developed ultrasonic uniaxial tensile test device. The specimen is designed that the both ends are square board,the middle is index profile,and single side opened a gap. The stress state of the notch specimen is theoretically analyzed,and the positive stress distribution formula of the notch groove section was obtained. By changing the notch groove depth t and curvature ρ of the specimen,it is obtained that the fatigue limit decreases with the deepening of the notch groove depth,reaching a minimum at a depth and then rising; the fatigue limit decreases with the decrease of the notch groove curvature,and reaches the minimum at a certain curvature,and then rises. The test shows that the fatigue limit is not only related to the stress concentration coefficient,but also to the depth of the grooves,stress gradient and other parameters,and the present work shows it is necessary to further study in this research field.
In order to study the fatigue performance of cracked workpiece under ultrasonic loading,the tensile test of notched 20 steel was carried out by self-developed ultrasonic uniaxial tensile test device. The specimen is designed that the both ends are square board,the middle is index profile,and single side opened a gap. The stress state of the notch specimen is theoretically analyzed,and the positive stress distribution formula of the notch groove section was obtained. By changing the notch groove depth t and curvature ρ of the specimen,it is obtained that the fatigue limit decreases with the deepening of the notch groove depth,reaching a minimum at a depth and then rising; the fatigue limit decreases with the decrease of the notch groove curvature,and reaches the minimum at a certain curvature,and then rises. The test shows that the fatigue limit is not only related to the stress concentration coefficient,but also to the depth of the grooves,stress gradient and other parameters,and the present work shows it is necessary to further study in this research field.
引文
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[2]TONG Jinglin,ZHAO Bo,BIAN Pingyan.Study on Fracture Mechanism of Ceramics under Ultrasonic Tension[J].Journal of Synthetic Crystals,2014,43(8):2132-2137.
[3]HE Bailin,YU Yingxia,et al.Effect of Ultrasonic Impact on Surface Structure and Fatigue Properties of Welded Cross Joint of Bogie[J].Transactions of the China Welding Institution,2013,34(8):51-54.
[4]REN Xuechong,CHEN Liqin,et al.Effects of Surface Ultrasonic Rolling Processing on Fatigue Properties of Axle Steel used on High Speed Train[J].Journal of Materials Engineering,2015,43(12):1-5.
[5]ZHANG Liaoyuan,SU Junjin,et al.Study on Mechanical Properties of Diamond Wire Saw under Ultrasonic Tension[J].Diamond&Abrasives Engineering,2017,37(4):41-43.
[6]CHENG Xueli,TIAN Changliu.Study on the Crack Extension Properties under Ultrasonic Vibration Uniaxial Tensile Load[J].Advanced Materials Research,2012,538-541:1751-1754.
[7]QIN Jun.Study on Mechanical Property of 20 Steel under Ultrasonic Vibration Simple Tension[D].Jiaozuo:Henan Polytechnic University,2007.
[8]Study on the Mechanical Behaviors and Damage Mechanisms of Alloys under Ultrasonic Fatigueloading[D].France:CNAM Paris France,1991.
[9]WIELKE B,SLANZL S.The Distribution of Plastic During21 k Hz Fatigue of Copper Samples[J].Ultrasonics,1976(3):227-231.
[10]ZANDMAN F.Photoelastic coating analyse stress[J].Prod Engng,1961,32(36):278-280.
[11]MAUNSELL F G.Stress in a Notched Plate under Tension[J].Phil Mag,1938,7(21):187-193.
[12]NEPPIRAS E A.Metal fatigue at high frequency[J].Proc Phys Soc,1977(1):67-70.