The issue of coupling the finite element method (FEM) and peridynamics (PD) is a critical concern of widespread attention in PD. In this paper, some essential insights into particle interfaces are presented to address the challenges of coupling PD with FEM and to mitigate surface effects. The interaction consistency between FEM and PD is demonstrated, and then a mechanical invariance of interactions is derived. This mechanical invariance serves as the foundation for an arbitrary switching FEMPD coupling (ASC), which allows for arbitrary switching between the two methods without introducing artificial deviations. Moreover, a strainbased surface effect correction (SBSEC) is developed to rectify surface effects by leveraging the symmetry of the strain tensor. This correction allows for the direct application of FEM boundary conditions onto PD boundary, thereby enhancing the precision of simulation results. The reliability of ASC is validated through quantitative deformation and fracture examples, while the excellent mitigation effect of SBSEC is illustrated. Furthermore, the examples related to composite materials highlight the promising potential of the proposed method for simulating composite materials.

中文翻译：

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对粒子界面的基本见解：从任意切换 FEM-PD 耦合到有效减轻表面效应

有限元法（FEM）和近场动力学（PD）的耦合问题是PD中广泛关注的一个关键问题。本文提出了一些关于粒子界面的重要见解，以解决 PD 与 FEM 耦合的挑战并减轻表面效应。证明了FEM和PD之间相互作用的一致性，然后推导出相互作用的机械不变性。这种机械不变性是任意切换 FEMPD 耦合 (ASC) 的基础，它允许在两种方法之间任意切换，而不会引入人为偏差。此外，还开发了基于应变的表面效应校正（SBSEC），通过利用应变张量的对称性来校正表面效应。这种校正允许将 FEM 边界条件直接应用到 PD 边界上，从而提高模拟结果的精度。通过定量变形和断裂实例验证了ASC的可靠性，同时说明了SBSEC优异的缓解效果。此外，与复合材料相关的例子凸显了所提出的复合材料模拟方法的巨大潜力。