Enhancing Damping in MEX ‐Fabricated ABS With Carbon Black: Free‐Decay Analysis, Estimator Fusion, and Mechanical Trade‐Offs

Acrylonitrile–butadiene–styrene (ABS) cantilever beams were reinforced with carbon black (CB) at 0–2 wt% and fabricated by mechanical extrusion (MEX)‐based additive manufacturing to improve vibration damping without compromising strength. Free‐decay responses were processed with three complementary estimators—logarithmic decrement (time domain), half‐power bandwidth (frequency domain), and an envelope‐fit that provides an analytic standard error—and the per‐run damping ratios were fused by precision (inverse‐variance) weighting to obtain a single with 68% confidence intervals. Composition‐level results show a clear optimum at 0.3 wt% CB, where the fused damping ratio increased from 5.81 × 10 −3 (pure ABS) to 7.75 × 10 −3 (≈+33%), while the ultimate tensile strength rose from 9.83 to 18.12 MPa (≈+84%). At 1 wt%, the damping remained elevated but strength decreased; at 2 wt% both metrics declined, consistent with agglomeration observed in scanning electron microscope images. A strength–damping Pareto view highlights 0.3 wt% as a practical composition window for balanced performance in MEX ABS/CB parts. The workflow—multi‐estimator analysis with uncertainty‐aware fusion—provides reproducible damping estimates from short free‐decay records and can be applied to other printed polymers and fillers.