The ring-rolling process was first developed in the UK in the mid nineteenth century and is still widely used as the preferred method of forming seamless rings for many aerospace and automotive applications, as well as for producing railway wheels and tyres. This thesis describes the development of a finite element based mathematical model that can be used to simulate the process. The model has been developed with the intention of practical application within railway wheel manufacturer Adtranz New Wheel Products Division. A detailed review of previous research on the process is presented. The key observation from that review is that all attempts at modelling ring rolling have suffered from severe run time difficulties which are predominantly due to lack of constraint and the large number of increments required to complete a simulation. Based on this fact the focus of development activities has been on identifying ways in which the simulation can be run in realistic time frames. The usefulness of a simplified 2D method is assessed, with the conclusion that while some beneficial information might be gained by such an approach, 3D simulation is the only way of fully representing material deformation during the process. Attempts at improving run time of 3D modelling have focused on two main areas. Firstly an efficient arbitrary Lagrangian Eulerian finite element flow formulation has been adopted. This gives the advantages of allowing mesh density to be concentrated on roll gap regions, and removing some of the convergence problems associated with frequent contact changes. Secondly the issue of solution of the discretised flow formulation equations is examined in some detail. A range of well known solution methods are considered as potential ways of improving on direct methods, with limited success. Significant potential benefits are found to result however from a new approach, the successive preconditioned conjugate gradient method. This method, together with tests of its effectiveness, is described in some detail. The resulting model is tested against experimental work performed by previous authors. Attempts to integrate the work into Adtranz are also described. These have included consideration of usability and management issues, and illustrative case studies.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:616283 |
| Date | January 1999 |
| Creators | Ward, Michael James |
| Publisher | University of Manchester |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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