Modeling post-process indenting using the discrete element method for particle density control in additively manufactured dampers

Laser powder bed fusion (LPBF), a technology within additive manufacturing, has demonstrated a remarkable ability to fabricate uniquely complex parts. One unique ability of LPBF is the integration of particle dampers by leaving areas of a part unfused during the manufacturing process. Particle dampers made in this way are fully integrated into the component and require no extra weight or materials. These attributes make them both cost- and production-effective. Previous work has indicated that changing the packing density of these particles by indenting the damper space can alter the qualities of the particle dampers, allowing for specific frequencies to be targeted. In this study, we propose using the discrete element method to model the effects of changing particle packing density in a particle damper created using LPBF. The discrete element method model can study the particles within the damper in greater detail and potentially gain more information than an experimental analysis. In this work, we model a 0.2×0.8×0.15 mm pocket containing approximately 1,300 particles. To simulate an indent compacting the particles, a sphere is created outside the pocket and moved partially into the pocket, reducing the available space for the particles. To validate the effectiveness of the models, we conduct multiple simulations with varying particle packing densities by altering the size and depth of the indent in the simulated pocket space. We then compare the pocket displacement over time across models under the vibrations and compare these results to experimentally obtained damping quality factors. Our findings suggest that the discrete element method model can demonstrate the effects of changing particle packing density in a particle damper by creating an indent in the damper space.