FöRFATTARE
Nilsson, Annika

DATUM
2000-12-18

INSTITUTION
Maskinteknik / Datorstödd maskinkonstruktion

SAMMANFATTNING
This thesis consists of seven papers. All deal with the modelling and simulation of metal working processes. The aim of the research has been to increase understanding of this kind of process by studying specific problems and making models. The processes that have been studied are hot rolling, bending and ironing. In this work experimental, numerical and empirical modelling is used.

In Paper 1 the springback in V-die bending was calculated using the finite element method. Springback was calculated for sheets of steel and aluminium with different thickness. The results were compared to experiments.

Paper 2 analyse an ironing process where friction and clearance distance were parameters of major importance for the outcome of the process. The sensitivity of the real process was confirmed in the FE simulation.

Paper 3 and Paper 4 concern unplanned asymmetric rolling. In paper 3 it was shown that many parameters influence front-end bending in plate. The main contribution with this paper is that the problem is studied using experimental design and the developed model shows the interacting parameters. Paper 4 studies strip tracking in a mill when the conditions in the roll gap vary over the strip width. The results show that it is important to regard the mill and the roll behaviour in the FE-model.

Paper 5 and paper 6 show the application of neural networks in rolling mills. In paper 5 a neural network based on temperature simulations is developed for the set-up of a finishing train. It is shown that a neural network trained on simulations can reproduce the results accurately. The neural network became considerably faster than the original physically based model. In Paper 6 a neural network is used for the force prediction in a plate mill. Different combinations of input data was tested for the model the results show that it is beneficial to include physically based data into the neural model and that the best model is obtained when the network is fed with data from the previous pass (adapted).

In the last paper the flatness in plate and strips is studied with the finite element method, a comparison was made between two different FE codes.

ISSN 1402-1544 / ISRN LTU-DT--00/41--SE / NR 2000:41