In deep-hole boring processes, boring bars with a large length-to-diameter ratio are typically employed. However, excessive overhang significantly reduces the boring bar’s stiffness, inducing vibrational effects that severely degrade machining precision and surface quality. To address this, the research objective is to suppress vibrations using a tunable-parameter boring bar. This paper proposes a novel Tunable Dynamic Vibration Absorber (TDVA) boring bar and designs its fundamental parameters. Based on the derived dynamic model, the vibration characteristics of the proposed boring bar are analyzed, revealing the variation in damping performance under different excitation frequencies. By establishing the relationship between TDVA stiffness, damping, and the axial compression of rubber bushings, optimal parameter combinations can be precisely identified for specific excitation frequencies. Ultimately, adjusting the TDVA’s axial compression displacement (0.1–0.5 mm) significantly expands the effective machining frequency range compared to conventional designs while maintaining operational reliability. This study proposes a novel Tunable Dynamic Vibration Absorber (TDVA) that innovatively integrates axial compression to achieve coupled stiffness and damping adjustments, addressing the rigidity–adaptability trade-off in deep-hole boring tools.

In this work, we establish a two-dimensional axisymmetric simulation model to numerically study the impacting behaviors between oil droplets and an immiscible aqueous solution based on the three-phase field method. The numerical model is established by using the commercial software of COMSOL Multiphysics first and then validated by comparing the numerical results with the previous experimental study. The simulation results show that under the impact of oil droplets, a crater will form on the surface of the aqueous solution, which firstly expands and then collapses with the transfer and dissipation of kinetic energy of this three-phase system. As for the droplet, it flattens, spreads, stretches, or immerses on the crater surface and finally achieves an equilibrium state at the gas–liquid interface after experiencing several sinking-bouncing circles. The impacting velocity, fluid density, viscosity, interfacial tension, droplet size, and the property of non-Newtonian fluids all play important roles in the impact between oil droplets and aqueous solution. The conclusions can help to cognize the mechanism of droplet impact on an immiscible fluid and provide useful guidelines for those applications concerning droplet impact.

In deep-hole boring processes, boring bars with a large length-to-diameter ratio are typically employed. However, excessive overhang significantly reduces the boring bar’s stiffness, inducing vibrational effects that severely degrade machining precision and surface quality. To address this, the research objective is to suppress vibrations using a tunable-parameter boring bar. This paper proposes a novel Tunable Dynamic Vibration Absorber (TDVA) boring bar and designs its fundamental parameters. Based on the derived dynamic model, the vibration characteristics of the proposed boring bar are analyzed, revealing the variation in damping performance under different excitation frequencies. By establishing the relationship between TDVA stiffness, damping, and the axial compression of rubber bushings, optimal parameter combinations can be precisely identified for specific excitation frequencies. Ultimately, adjusting the TDVA’s axial compression displacement (0.1–0.5 mm) achieves a 22% expansion in the effective machining frequency range.