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| Author(s): |
Roseli Noriko Suzuki Fassani
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Faculdade de Engenharia Mecânica |
| Defense date: | 2001-02-19 |
| Examining board members: |
Osvair Vidal Trevisan;
Marcelo Moreira Ganzarolli;
Sérgio Tonini Button;
Celio Taniguchi;
Claudio Shyinti Kiminami
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| Advisor: | Roseana da Exaltação Trevisan; Osvair Vidal Trevisan |
| Abstract | |
In multiple pass welding process, the material undergoes fast cycles of heating and cooling. Materials subjected to phase changes may undergo microstructural modifications, resulting in alterations in their mechanical properties. The knowledge of the thermal cycle for a specific position gives important informations about the peak temperature and the cooling rate, which indicate possible phase changes in the weldment. In this work, analytical and numerical models were developed for onedimensional and two-dimensional transient heat flow, and also for two-dimensional and three-dimensional steady-state heat flow. The distributed heat source and heat loss were taken into account in the analytical models. Besides convective and radiative heat losses, the change of physical properties with temperature was studied in the numerical models. The main contribution of this work was to provide original analytical solutions for the multipass welding process, in accordance with the heat flow and the mentioned topics. The thermal cycles provided by the analytical solutions were checked against the thermal cycles simulated by the numerical solutions. In one-dimensional transient and two-dimensional steady-state heat flow, the analytical and numerical thermal cycles were compared with those obtained in a experimental setup. The agreement between analytical, numerical and experimental results shows the validity of the proposed analytical models. The advantage of these models is that the influence of the welding parameters, material and plate thickness on the thermal cycle may be assessed in a confident and straightforward manner (AU) | |