A virtual material-based static modeling and parameter identification method for a BT40 spindle-holder taper joint

The static characteristics of a taper joint interface play a key role in the static behavior of the entire spindle system of a machine tool. In this study, a method of modeling a taper joint and identifying its parameters is proposed to describe the static behavior of a taper joint. First, a static model is constructed based on a virtual material layer and equilibrium functions established to identify the unknown parameters of the virtual material. Then, an experimental method is introduced to acquire joint interface data for parameter identification based on a designed spindle-holder characteristic test system. In particular, a BT40 taper joint holder is studied taking into account the pre-force at the end of the holder. The study results show that the static stiffness increased initially with the growth in the pre-force and became relatively stable after reaching a value which could be explained by its microstructure. According to the simulation results, the effectiveness of the proposed virtual material modeling method, compared with previous methods, are discussed. The estimated parameters are informative for the design and manufacture of the spindle.