This thesis presents a theoretical and experimental investigation into the modelling of the electro-fusion process, applied to welding polymer pipes. The theoretical background of the transient heat transfer between the fitting and pipe, including variable interface thermal resistance and involving consecutive changes of phase (melting and re-solidification) and the problem of the thermo-mechanical induced stresses in the joint, are fully discussed. Three 2D axisymmetric models of the EFW process, with different degrees of complexity, have been developed, refined and validated by comparison with experimental data: a finite element coupled model, with both temperature and displacement degrees of freedom, and two sequential heat transfer models, finite element and finite difference based. The effect of the melt movement into the fitting-pipe initial clearance is discussed and has been modelled by a 'virtual material movement' method. For the sequential models a 'gap evolution model' has been developed to describe the closure of the initial fitting-pipe gap through the process. Results from the simulations of the electro-fusion welding process performed using all three models, which give an exceptionally good insight into the temperature, displacement and stress fields within the joint, are fully discussed and validated through comparison with experimental data.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:574642 |
| Date | January 1995 |
| Creators | Rosala, George Florin |
| Publisher | University of Bradford |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
Page generated in 0.0019 seconds