Shot peening has been widely used in processing various components since it can bring in residual compressive stress and effectively refine the grain size of impacted area. To simulate grain refinement induced by shot peening, the dislocation density-based model has recently been introduced, however, the existing time integration algorithm is not stable and usually leads to divergent solutions in iterations. In this paper, a novel time integration algorithm is proposed for the dislocation density-based model. Based upon the algorithm, numerical studies on multi-shot AISI4340 steel are carried out with different coverages, velocities, shot diameters, and peening angles. It is shown that the method converges faster than the two-level iteration method, and the predicted dislocation cell structure sizes after shooting are consistent with experimental results. Besides that, increasing coverage can refine the size of a dislocation cell, which is closely dependent on the shot diameter, impact velocity, and angle. Thus, to achieve the desired grain size or the depth of refinement, it is necessary to take the shot diameter and velocity into account simultaneously.

中文翻译：

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使用新颖的时间积分算法基于位错密度模型模拟喷丸

喷丸强化可以带来残余压应力并有效细化受影响区域的晶粒尺寸，因此被广泛应用于各种零件的加工。为了模拟喷丸引起的晶粒细化，最近引入了基于位错密度的模型，然而，现有的时间积分算法不稳定，通常会导致迭代中的解发散。本文针对基于位错密度的模型提出了一种新颖的时间积分算法。基于该算法，对不同覆盖范围、速度、弹丸直径和喷丸角度的多弹AISI4340钢进行了数值研究。结果表明，该方法比二级迭代方法收敛速度更快，并且预测的射击后位错单元结构尺寸与实验结果一致。除此之外，增加覆盖范围可以细化位错单元的尺寸，这与弹丸直径、冲击速度和角度密切相关。因此，为了达到所需的晶粒尺寸或细化深度，必须同时考虑弹丸直径和速度。