【作者】 王强；

【导师】 杨庆祥； 高玉魁；

【作者基本信息】 燕山大学 ， 材料学， 2006， 硕士

【摘要】 本文研究了不同喷丸工艺对高强度钢试样喷丸后残余应力场的影响,并采用有限元法对喷丸后产生的残余应力场进行了数值模拟。用X3000型X射线仪测定残余应力,并使用电解抛光法逐层测定残余应力的分布。同时,利用X射线衍射仪对喷丸前后试样晶体结构进行分析,测量了试样表面显微硬度沿层深分布,并对试样组织形貌进行了观察。用ANSYS软件建立有限元模型,通过调整弹丸速度、弹性模量和直径大小进行喷丸过程的模拟分析。随着喷丸时间的增加,最大残余压应力深度和强化深度增大,表面残余压应力减小;和小直径弹丸相比,使用大直径弹丸喷丸产生的强化深度较大;随着喷丸强度的增大,最大残余压应力、强化深度增加;采用玻璃丸或陶瓷丸进行二次喷丸提高了试样表面残余压应力。喷丸后高强度钢试样表面位错数量增加;试样表面显微硬度提高。用ANSYS软件建立有限元模型模拟喷丸过程,在模型中考虑了试样的各种参数,获得了不同喷丸参数下残余应力场的变化规律。模拟结果与实验结果较相符,证明了模型的可参考性,取得了比较好的结果。更多还原

【Abstract】 The effect of different shot-peening regimes on residual stress fields of the high strength steel was investigated and simulated by using a finite element method.By employing the X3000 X-ray diffraction stress analyzer and the electrochemical polishing method, the residual stress of the high strength steel along the shot-peened layer was determined layer by layer. Buy using X-ray diffraction analyzer, the crystal structure of specimen after shot-peening was analyzed. Meanwhile, the micro-hardness distribution along the shot-peened layer was determined, and the microstructure of the high strength steel was also observed. A model was proposed by using a finite element method and it was simulated by employing different velocities, rigidities and diameters of shots. The experimental results indicate that, with increasing of the shot-peening time, both depths of maximal compressive residual stress and shot-peened layer are increased, while, the value of surface compressive residual stress is decreased. The depth of shot-peened layer is strongly affected by the diameters of shot and the value of residual stress is improved when the diameter of shot is increased. With the increasing of the shot-peening intensity, the maximal compressive residual stress and depth of shot-peened layer are improved. The surface compressive residual stress is increased after secondary shot-peening by using glass or ceramic shot.After shot-peening, both the number of dislocation and micro-hardness increase.The finite element model of shot-peening was established by the software ANSYS. In this model, a few important parameters were considered and different results of residual stress fields were obtained. The simulated results are agreed to the experimental one therefore, this model is effective and can be employed to predict the residual stress fields of shot-peened specimens.更多还原