Structural design and parameter optimization of a vibration absorber for rescue casing-while-drilling rigs

ObjectiveRescue drilling rigs undergo intense vibration at borehole mouths when operating in a confined underground space of coal mines. To address this issue, this study designed a compact multi-directional, passive dynamic vibration absorber, aiming to improve the operational stability and safety of the rigs. MethodsBased on the spring-mass-damping system theory, a stepwise optimization design method was proposed for the longitudinal and transverse dynamic models of the vibration absorber. For the longitudinal vibration model, the particle swarm optimization (PSO) algorithm was applied for multi-objective parameter optimization. In contrast, for the transverse vibration model, the fixed point theory was employed for precise design. This design method enabled the optimal parameter matching of various components under the constraint of limited space. The performance of the designed absorber in multi-dimensional vibration suppression was verified using numerical simulations and engineering tests. ResultsResults from numerical analysis and field tests indicate that the designed absorber can significantly suppress the longitudinal and transverse resonance at borehole mouths for rescue drilling rigs while maintaining a compact structure. Field tests conducted under the set operating conditions (working pressure: 28 MPa; inner pipe rotation speed: 16 r/min; outer pipe rotation speed: 8 r/min) demonstrate that the absorber reduced the transverse and longitudinal vibration amplitudes of the drilling rig by 60% and 51.34%, respectively, confirming its effectiveness in practical engineering applications. ConclusionesThe proposed absorber with a compact structure and reliable performance provides a solution for the vibration control of rescue drilling rigs in a confined space, offering a valuable reference for the vibration reduction design of engineering equipment under similar operating conditions.