Particle dampers represent a simple yet effective means to reduce unwanted oscillations when attached to structural components. Powder bed fusion additive manufacturing of metals allows to integrate particle inclusions of arbitrary shape, size and spatial distribution directly into bulk material, giving rise to novel metamaterials with controllable dissipation without the need for additional external damping devices. At present, however, it is not well understood how the degree of dissipation is influenced by the properties of the enclosed powder packing. In the present work, a two-way coupled discrete element - finite element model is proposed allowing for the first time to consistently describe the interaction between oscillating deformable structures and enclosed powder packings. As fundamental test case, the free oscillations of a hollow cantilever beam filled with various powder packings differing in packing density, particle size, and surface properties are considered to systematically study these factors of influence. Critically, it is found that the damping characteristics strongly depend on the packing density of the enclosed powder and that an optimal packing density exists at which the dissipation is maximized. Moreover, it is found that the influence of (absolute) particle size on dissipation is rather small. First-order analytical models for different deformation modes of such powder cavities are derived to shed light on this observation.

翻译：颗粒阻尼器是一种简单而有效的方法，可在附加于结构部件时减少不必要的振动。金属粉末床熔融增材制造技术能够将任意形状、尺寸和空间分布的颗粒内含物直接集成到块体材料中，从而产生新型超材料，无需额外外部阻尼装置即可实现可控耗散。然而，目前尚不清楚封闭粉末堆积的特性如何影响耗散程度。本研究提出了一种双向耦合的离散元-有限元模型，首次能够一致地描述可变形振荡结构与封闭粉末堆积之间的相互作用。作为基本测试案例，考虑了填充有不同堆积密度、颗粒尺寸和表面性质的粉末堆积的空心悬臂梁的自由振荡，以系统研究这些影响因素。关键的是，发现阻尼特性强烈依赖于封闭粉末的堆积密度，并且存在一个使耗散最大化的最优堆积密度。此外，发现（绝对）颗粒尺寸对耗散的影响较小。推导了此类粉末空腔不同变形模式的一阶解析模型，以阐明这一观察结果。