Ergebnisse aus der Produktionstechnik / 18/2023 / Substructuring Methods for Efficient Prediction of Spindle-Holder-Tool Assembly Dynamics

This thesis provides a framework of efficient experimental and analytical substructuring methods for the reliable prediction of spindle-holder-tool assembly dynamics. Specifically, the prediction of the tool tip Frequency Response Functions (FRFs) as well as the tool tip-Spindle Integrated Displacement Sensors (SIDS) transfer functions for a main spindle equipped with contactless displacement sensors. Here, the holder-tool assembly is modelled analytically whereas the spindle substructure is modelled experimentally. For achieving high-quality experimental response models, three important aspects are researched. Firstly, strategies for measurement of displacement-to-force compliances are systematically compared and assessed. Secondly, two new methods for the identification of rotational compliances are proposed based on a modal parameter approach and commercially available rotational accelerometers. Thirdly, an experimental method for obtaining the interface flange-SIDS transfer function matrix and corresponding measurement uncertainty is developed and validated. This is required for prediction the tool tip-SIDS transfer function along with propagated uncertainty bounds. A significant challenge in the analytical response modelling of holder-tool assemblies is that features like joint parameters cannot practically be modeled a priori and require additional reference measurements for their parametrization. This thesis proposes an extended tool model updating approach, where FRFs of the holder-tool assembly measured in an offline, freely constrained state are used for feature parameterization. Using this approach, a priori unknown parameters like joint stiffness and effective diameter of the fluted segment are reliably identified and validated for several different holder-tool assemblies. Furthermore, methods for the accurate beam modelling of various holder features such as balancing holes, tapered segment and holder-inserted tool segment were developed, analyzed and