喷丸强化残余应力场三维数值仿真分析

建立了喷丸强化三维有限元模型，实现了喷丸强化处理残余应力场的数值仿真。根据显式动力分析各种能量变化过程，确定了显式分析求解时间选择方法；研究了喷丸速度、弹丸直径、入射角度及摩擦力等因素对喷丸残余应力场影响的一般规律，并与现有相关文献试验结论进行对比；分析了单次和多次冲击下材料内部的残余应力场分布及塑性应变分布特点；建立了不同数目的多丸粒喷丸强化三维有限元模型，研究不同覆盖率对残余应力场分布的影响规律。数值分析结果表明，喷丸速度、弹丸大小、入射角度对残余应力场分布有显著影响。冲击次数对残余应力幅值影响小，但等效塑性应变增加明显。喷丸覆盖率的增加会显著改变残余应力场，并使残余应力场分布更加均匀，但残余压应力幅值与喷丸覆盖率没有必然相关性。

Three-dimensional Numerical Simulation of Residual Stress Field for Shot-peening

This investigation is devoted to the modeling and simulation of the residual stress field resulting from the shot-peening process, in which the finite element method was employed. The history of energies during explicit dynamic analysis is discussed and the solution time for explicit analysis is analyzed by shock wave theory. For the single shot impact model, the study examines the effect of shot velocity,shot size, incident angle and interfacial friction and the comparison was made with the published experimental results. Furthermore, the effect on the residual stress field and equivalent plastic strain on the target plate of the shot-peening frequency was studied. The influence of coverage ratio on the residual stresses field is investigated by conduct dynamic elasto-plastic finite element analysis of the process using a realistic multiple impingement model. The analysis results indicate that shot and target parameters play the important role on the quality of the treatment. The residual stresses are not significantly affected by the peening frequency, but the equivalent plastic strain increases with the peening frequency. The residual stress distribution are highly dependent on multiplicity. A uniform state of stress was achieved with the increase of the coverage ratio.