Experimental based coupling of substructures for vibration analysis of machine tools

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The dynamic behavior of machine-tools determines their accuracy and performance. The modification of machine-structures lying within the force flux or the variation of the position of the machine-axis changes the dynamic behavior of the machine at the Tool Center Point. Since such design modifications occur frequently, machine-tool manufacturers try to predict the dynamic behavior of the modified system. The currently implemented methods require an elaborate simulation of the complete machine and its comparison with measurements of a physical prototype.The goal of this research proposal is the development of a method for predicting the effect of structural modifications on machine dynamics using experimental data. Experimental substructure-coupling offers an efficient solution, where the modified structure is described analytically and the unchanged base-structure is described experimentally.In the 1st funding period, coupling-equations for frequency-based substructure-coupling were extended for machine-tools. The procedure for analytical model-building was optimized and implemented in a software-framework, such that simple structures could be modeled accurately without comparison with measurements. This method was successfully implemented for two test-cases (prediction of position-dependent dynamics and design of passive damping systems).However, the developed method necessitates the disassembly of components in order to measure the coupling-points. For this, substructure-decoupling enables the identification of coupling-point properties without disassembly. Hence, methods for modal and frequency-based substructure-decoupling for application in machine-tools will be developed in the 2nd funding period. Apart from the identification, the experimental determination of coupling-point properties is a further goal. Finally, the developed methods will be validated for different applications in machine-tools.