A method to select the finite element models for the structural analysis of machine tools

This paper presents a method to select the finite element models for the structural systems of machine tools. The method based on the analysis of modelling results obtained for three different machine tools using the different variants of models. Performed numerical experiments have been shown that the most accurate model is one that involves modelling of feed drives and joints. Increased computational costs, however, may reduce applicability of the model. It was found that the elimination of the feed drives from the numerical model of a machine tool increases the error of modelling (up to 25 %) when static analysis performed. The results of modal and harmonic analysis are more stable to changes introduced to the numerical model of a machine tool, as the error of calculated parameters does not exceed 10 %. Moreover, it was found that the numerical models, which include preloaded joints with stiffness more than 16000 N/μm, are different a little from the models with ideal contact. Thus, it was shown that the use of the machine tool's numerical model without non-ideal contact and feed drives is more preferable if the acceptable error of modelling does not exceed of 25 %.