Purpose <p>Bandgap-tunable metamaterials have attracted considerable interest because of their potential use in sensing and logic manipulation. This paper introduces a novel single-beam honeycomb metamaterial (SBHM) design based on a honeycomb structure.</p> Methods <p>A dynamic model of the SBHM is developed, and the frequency response is computed using the spectral element method (SEM). The accuracy of the SEM is confirmed through comparisons with finite element method (FEM) results and band structure analysis. Additionally, a bandgap-tunable SBHM incorporating adaptive external excitation is designed. The shape, frequency response, and bandgap characteristics of the bandgap-tunable SBHM are analyzed using SEM and band structure analysis.</p> Results <p>Findings show that the SBHM structure exhibits a wide Bragg bandgap, with frequency response closely matching the band structure analysis, confirming its strong vibration attenuation capability. Notably, the bandgap-tunable SBHM can deform under varying loads, allowing adjustment of both bandgap width and position. The structure also shows three distinct bandgap shifts when external forces change.</p> Conclusions <p>This adaptability in bandgap control makes the bandgap-tunable SBHM a promising candidate for practical applications. This research offers a valuable framework for designing bandgap-tunable elastic metamaterial beams, improving their tunability, and controlling elastic wave propagation.</p>