Identification and evaluation of uncertainties and errors in dynamic models of casted machine tool components

摘要

When calculating the dynamic properties of machine tools by means of the finite-element-analysis, highly correlated component models are needed for the derivation of an accurate model of the assembled machine tool structure. For casted machine tool components this cannot always be ensured due to the significant geometric and material uncertainties inherent in the casting process. In this paper, a stepwise modelling approach for casted machine tool components is proposed that allows the derivation of highly correlated models in a defined frequency range. Based on the assumption of superposition the uncertainties and errors involved in the modelling process are identified and evaluated by means of strain energy considerations. By applying this approach to a casted machine tool column, the initial frequency deviations for the considered first 15 structural modes of up to 15% from the measured values could be reduced below 3%. Also deeper insight was gained about the influence of the considered uncertainties and errors on the model correlation, as the deviations could be assigned to their sources.