喷丸强化在改善螺栓抗疲劳性能中的应用

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The bolt used in compressor often causes fatigue failure under dynamic load. By the finite element software ABAQUS,2D bolt model and 3D bolt model for single shot-peening process were built. The results of 2D model analysis show that the stress concentration value at the first thread of bolt and nut meshing is the greatest, where the fatigue failure is easy to occur; The stress concentration value at the transition section of bolt shaft and end is the minimum. The analysis results correspond with the real situation. Through 3D shot-peening model analysis of bolt, the real bolt stress and strain values under different load were calculated, and the stress concentration value of different bolt sections and fatigue life value were obtained. By the comparison of the fatigue life before and after shot-peening processing, the results show that after shot-peening processing, the anti-fatigue property of bolts is improved. So it is feasible to improve the anti-fatigue property of bolts by shot-peening processing, and the possibility of seal connection is enhanced.压缩机用螺栓在动载荷作用下，常常会产生疲劳失效破坏。应用有限元软件ABAQUS建立螺栓的二维模型和单个弹丸撞击螺栓的三维有限元模型。螺栓的二维模型模拟分析表明，在螺母与螺栓旋合的第一扣处的应力集中系数最大，该处最易出现疲劳破坏，而螺栓杆与螺栓头过渡处的应力集中系数最小，模拟分析结果和螺栓疲劳破坏的实际情况完全相符。采用三维喷丸模型模拟分析得到螺栓在不同载荷作用下单元的实际应力应变值，求出相应的螺栓疲劳寿命。通过对比螺栓喷丸前后的疲劳寿命，发现喷丸处理后螺栓疲劳寿命得到了很大提高，表明利用喷丸工艺提高螺栓的疲劳性能是可行的，提高了密封连接的可靠性。