A study on energy dissipation in additively manufactured beams with powder-filled cavities: experimental characterization and modeling directions.
Speaker
Roy van den Putte
About this event
The increasing performance demands of high-performance mechatronic systems require structures that combine low mass, high stiffness, and damping. Additive manufacturing, particularly Laser Powder Bed Fusion (LPBF), enables the integration of powder-filled cavities that can provide passive damping without additional components. However, the underlying energy dissipation mechanism is not yet sufficiently understood. This thesis investigates the modal damping behavior of LPBF-manufactured beam specimens containing powder-filled cavities. Force-amplitude-controlled stepped-sine excitations and frequency response function measurements were used to experimentally characterize the nonlinear, force-amplitude-dependent damping. Specimens with varying cavity heights and positions were investigated. In addition, finite element analysis was performed to determine the strain distribution around the cavities. The experiments showed that damping increases with excitation force amplitude and approaches a constant value at high amplitudes. Cavity position along the beam length was identified as the most influential design parameter, with maximum damping occurring near regions of maximum modal strain. Higher cavities also increased damping by extending into regions of enhanced strain. Comparison with an empty cavity confirmed that the damping originates from the enclosed powder. The results support a friction-based energy dissipation mechanism caused by interactions between powder particles and the cavity walls. Based on these findings, a numerical modeling approach combining FE structural dynamics with friction models such as the Iwan or Jenkins model is proposed.
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