冷喷涂中粒子与基体的高速冲击过程

High-velocity impact process between paritcle and substrate in cold spraying

利用非线性动力分析软件LS-DYNA,对冷喷涂中铜粒子与铜基体的碰撞过程进行了3维数值分析。研究沉积粒子与被喷涂基体的变形行为以及影响数值模拟结果的关键因素。数值模拟结果表明:通过3维模型获得的铜粒子与铜基体在碰撞结束后的沉积形貌与实验观察吻合很好,比采用2维模型获得的模拟结果更精确。另外,3维模型的网格尺寸对喷涂粒子的临界速度和粒子的变形行为也有很大影响,随着网格尺寸的减小,粒子的临界速度及扁平率逐渐减小,压缩率逐渐增大,利用插补法获得的网格尺寸为0时的铜粒子临界速度、扁平率及压缩率与实验结果吻合很好。

Copper particle impact behaviors in cold spraying were numerically simulated by using the LS-DYNA program.Some important aspects on the 3D modeling were examined.Effects of the meshing size on particle critical velocity and particle deformation were also investigated.The results show that the contours of the deformed particle obtained by the 3D model are more comparable to the experimental observation than the previous 2D simulated results.The distortion of the solid element at the contact zone in the 3D model is much weaker than the surface element used in the 2D model.Therefore,no steep increase of effective plastic strain of elements can be observed during the impact process.Furthermore,the meshing size also takes an important role in the 3D simulated results.The critical velocity,flattening ratio and compression ratio obtained by extrapolation methods are in good agreement with the experimental results.