Rovnání hutního materiálu tříbodovým ohybem s využitím analytického a numerického řešení

Abstract

The submitted thesis deals with the straightening of billets especially with square cross section using three-point bending. At beginning, state-of-the-art is presented. Followed by methodology of straightness evaluation and the criteria of straightness parameters are defined. Two possibilities of analytical approach are presented for the deflection calculation of the sleeve. The first one is based on geometrical properties of deformed idealized beam middle axis and the assumption that relationship for total deflection to plastic deflection for specific material is known. The second approach uses the analytical method using momentum equations and ideally elastic-plastic material. The results from both approaches are compared with the numerical solution obtained by finite element method. New add-on application was created to enable easier workflow for data evaluation from the working process of the straightening of billets. Further, another add-on application was created which enables to run the full straightening process simulation using the finite element method following data postprocessing. Particular finite element studies have been performed within the work on task of straightening of billets. First of all, the overall process of straightening has been simulated. The results have been compared with the measurement and it proves the straightening algorithm functionality. The so-called ‘boost factor’ was found to streamline the straightening process. Above mentioned ‘boost factor’ is mainly used for billets that have an excessive input straightness deviation from especially for billets in shape of bow. Moreover, the redistribution study was performed from one stroke approach to two strokes approach, which is realized especially as a prevention of the breaking of billet. Finally, finite element analysis with 3D model with consideration of supports physical shape has been performed. Obtained results from simplified model analyses considering supporting elements only as boundary as well as full 3D model including supporting shape has been compared. At the end, the analysis using 3D shape including worn out supports has been performed.