THE METHOD OF SELECTION THE SOLID FINITE ELEMENT MODELS OF LOAD-BEARING SYSTEMS OF MACHINE TOOLS WHEN PERFORMING ENGINEERING ANALYSIS

Abstract

The paper presents a methodology for the selection of a solid finite element models for load-bearing systems of machine tools. The technique is based on the analysis of the results of computer simulation of different models of load-bearing systems of three machines with different layouts. The variability of the models is determined taking into account the traction devices and joints in the conjunctions. The traditional approach for modeling the non-ideal joint in the form of elastic elements set is used, despite the fact that modern CAE systems for modeling non-ideal contact in mates offer special contact finite elements. The conducted computational experiments demonstrate that the most accurate model is obtained by using models of traction devices and joints. In this case, the computational model requires significant computational resources. It is found that the exception of the design model of the bearing system of the machine traction devices can lead to an increased modeling error in static problems up to 25 %. The results of modal and dynamic calculations are more resistant to changes in the design model of the machine, as the error of the design parameters does not exceed 10 %. In addition, the computational models of tightened joint, with a stiffness of more than N/m, are not much different from models with ideal contact. It is shown that with an acceptable 25% modeling error, it is preferable to use a computational model of the load-bearing system without taking into account the non-ideal contact and traction devices