Metastructured Drill Pipe and Its Three-Directional Coupled Vibration Damping Mechanism

To address the problem that longitudinal, lateral, and torsional vibrations of drill pipes during oil and gas well drilling, as well as their coupled interactions, are difficult to effectively control, this paper proposes a novel drill pipe structure based on the principle of local resonance--the metastructured drill pipe. Through finite element analysis, this study calculated the band structure, characteristic modal displacement fields, and vibration transmission characteristics under finite periodicity, systematically explaining its bandgap properties. The research results show that the designed locally resonant metastructured drill pipe opens a complete three-directional bandgap in the range of 44.30 Hz to 81.14 Hz, which can effectively suppress the propagation of three types of vibrations, including longitudinal, lateral, and torsional vibrations. Mechanism analysis indicates that this bandgap originates from the simultaneous suppression of the three primary modes of the host shaft by the local resonators, thereby hindering the propagation of the three wave modes, forming a complete bandgap. Further parameter studies show that by adjusting the structural parameters of the local resonators, the position and width of the bandgap can be effectively tuned. The metastructured drill pipe concept proposed in this paper provides a new theoretical approach to address the shortcomings of traditional methods in controlling multi-directional coupled vibrations of drill pipes, offering a new guided solution for drill pipe vibration control under complex downhole conditions in oil wells.