【摘要】 对螺纹根部进行超声滚压强化，可引入有益的残余压应力，这对提升螺纹件疲劳寿命至关重要。但因螺纹根部圆弧尺寸较小，测量其残余应力场分布存在较大难度。为深入探究超声滚压对螺纹根部R区表层残余应力场的影响，通过试验确定了34CrNiMo6合金钢的Johnson-Cook(J-C)本构及损伤模型参数，建立了具有螺纹升角的外螺纹根部R区超声滚压仿真模型，采用自制M30×6外螺纹试样对该模型进行了试验验证，并采用该模型仿真分析了不同超声振幅对小规格外螺纹根部R区残余应力的影响。结果表明：螺纹根部R区残余应力随着振幅的增大而增大，但当超声振幅超过16μm时，螺纹牙底两侧出现损伤，且随着振幅增大，损伤越明显，在一定程度上可为试验参数的选取提供参考。更多还原

【Abstract】 Ultrasonic rolling applied to the thread root introduces beneficial residual compressive stress, which is crucial for improving the fatigue life of threaded components. However, measuring the distrution of the residual stress field is challenging due to the small arc radius of the thread root. To further investigate the influence of ultrasonic rolling on the surface residual stress field in the R-zone of threads root, experiments are conducted to determine the Johnson-Cook(J-C) constitutive and damage model parameters of 34CrNiMo6 alloy steel. A finite-element model that takes the helix angle into account is built for the ultrasonic rolling of the root-R zone of external threads. This model is validated using custom-fabricated M30×6 external thread specimens, and is further used to simulate and analyze the effects of different ultrasonic amplitudes on the residual stress within the root-R zone of small-sized external threads. Results show the residual compressive stress in the thread root-R zone increases as the amplitude rises. However, when the ultrasonic amplitude exceeds 16 μm, damage appears on both sides of the thread root, and the severity of the damage increases accordingly. These findings may provide some insight into selecting appropriate experimental parameters.更多还原