Micro-particle impact is a problem of solid mechanics that is common in many applications. To address this problem, a new soft-particle DEM model of micro-particle impact is proposed, which incorporates adhesive, elastoplastic and microslip behaviors. The normal force model is developed as two contiguous loading stages: the elastic stage and the elastoplastic stage in which the transition is from the elastic deformation to fully plastic deformation. Most innovative in unloading, the normal force model is also evolved into two contiguous stages: unloading under elastic loading and unloading under elastoplastic loading in which it combines Hertz elastic model and Mesarovic-Johnson plastic model. The normal force model is further assumed as the one-way coupling with pressure-based Maw tangential model with the micro-slip behavior. Further model validations are performed by employing the experimental results in literatures. The validation results indicate that model predictions agree with the experimental data, and are demonstrated to be incredibly accurate than other models, particularly for restitution coefficients and critical sticking velocity. Furthermore we can find that the smaller size particle has a longer period of nonlinear loading, while the larger size particle has a longer period of linear loading. For tangential restitution coefficient at the small incident angle, a down trend may be due to the oscillation of the tangential force.

微粒撞击是许多应用中常见的固体力学问题。为了解决这个问题，提出了一种新的微粒撞击的软微粒DEM模型，该模型结合了粘合，弹塑性和微滑行为。法向力模型被开发为两个连续的加载阶段：弹性阶段和弹塑性阶段，在该阶段，从弹性变形过渡到完全塑性变形。法向力模型在卸荷方面最具创新性，它也演化为两个连续的阶段：弹性荷载下的卸荷和弹塑性荷载下的卸荷，其中结合了Hertz弹性模型和Mesarovic-Johnson塑性模型。法向力模型被进一步假定为具有微滑动特性的基于压力的莫氏切向模型的单向耦合。通过利用文献中的实验结果进行进一步的模型验证。验证结果表明，模型预测与实验数据相符，并且被证明比其他模型准确得多，尤其是在恢复系数和临界黏着速度方面。此外，我们发现较小尺寸的粒子具有较长的非线性加载时间，而较大尺寸的粒子具有较长的线性加载时间。对于小入射角处的切向恢复系数，下降趋势可能是由于切向力的振荡引起的。特别是对于恢复系数和临界黏着速度。此外，我们发现较小尺寸的粒子具有较长的非线性加载时间，而较大尺寸的粒子具有较长的线性加载时间。对于入射角较小的切向恢复系数，下降趋势可能是由于切向力的振荡所致。特别是对于恢复系数和临界黏着速度。此外，我们发现较小尺寸的粒子具有较长的非线性加载时间，而较大尺寸的粒子具有较长的线性加载时间。对于小入射角处的切向恢复系数，下降趋势可能是由于切向力的振荡引起的。