In this paper, a computational atomistic-continuum multiscale framework is presented for the simulation of the nano-powder compaction process using a cone-cap plasticity model. The atomistic representative volume element (RVE) comprises of nano-powder particles that is used to perform the molecular dynamics analysis in order to capture the mechanical behavior of nano-powder material. The periodic boundary condition is applied over the atomistic RVE to satisfy the inter-scale kinematic compatibility, and the stress tensor is derived according to the inter-scale energetic consistency principals from the nanoscale at each material point of the powder component. A multiscale framework is performed using the constitutive law of the coarse-scale domain enhanced by the molecular dynamics results of the fine-scale domain. The coarse-scale constitutive law is conformed to the cone-cap plasticity model as a robust and capable constitutive relation in modeling the powder compaction process, in which the cap plasticity parameters are determined using the data derived from the molecular dynamics simulations. The mechanical response of nano-powder particles within the RVE is obtained from the confining pressure test and true-triaxial test, where a sensitivity analysis is accomplished on the computed parameters of the cone-cap plasticity model. The enhanced cap plasticity model is then employed to simulate various industrial nano-powder components that illustrates the performance and efficiency of the proposed multiscale computational homogenization method.

在本文中，提出了一种计算原子连续体多尺度框架，用于使用锥盖塑性模型模拟纳米粉末压实过程。原子代表体积元素 (RVE) 由纳米粉末颗粒组成，用于执行分子动力学分析以捕获纳米粉末材料的机械行为。周期性边界条件应用于原子 RVE 以满足尺度间运动学相容性，应力张量根据粉末组分每个材料点的纳米尺度的尺度间能量一致性原则导出。使用由细尺度域的分子动力学结果增强的粗尺度域的本构定律来执行多尺度框架。粗尺度本构定律符合锥帽塑性模型，作为粉末压实过程建模中稳健且有效的本构关系，其中帽塑性参数是使用分子动力学模拟得出的数据确定的。RVE 内纳米粉末颗粒的机械响应是通过围压测试和真三轴测试获得的，其中对锥帽塑性模型的计算参数进行了灵敏度分析。然后采用增强的帽塑性模型来模拟各种工业纳米粉末成分，说明所提出的多尺度计算均质化方法的性能和效率。