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Title: Virtual fabrication of full size welded steel plate girder specimens
Author: Nezo, Janos
ISNI:       0000 0004 2741 5791
Awarding Body: Heriot-Watt University
Current Institution: Heriot-Watt University
Date of Award: 2011
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The use of virtual experiments of welded steel plate girders are commonplace in modern structural research. One key factor in the success of using such numerical analysis is the availability and reliability of input data including imperfections such as initial deformations and residual stresses. In this research a methodology combining experimental and numerical work is developed in order to use virtually fabricated welded specimens, which include the imperfections as a result of the manufacturing process, in virtual experiments. A series of experiments are performed to calibrate and validate the numerical models. Temperature measurements are conducted in a steel structure factory during the welding of plate girders. The measurement methodology developed combines two types of measurements using an infrared thermometer without disturbing the fabrication process itself. The residual stresses are measured using a modified hole drilling method. Geometrical imperfection measurement results are also available from other related projects. For the numerical simulation of welding a mixed time integration scheme is proposed. For the modelling of the heat source of welding an “equivalent prismatic heat source model” is developed, which is very robust and allows for very simple calibration. Both thermal and thermal stress analyses of the welding process are performed including a large number of parametric studies. The residual stress measurements are also numerically investigated and calibration tables are developed to evaluate the measurements considering inaccuracies in their execution. The fabrication of full size plate girders is simulated. The calculated and measured web deformations are compared and reasonable agreement is found. Finally, to demonstrate and summarise the achievements of this research, a virtual specimen is used in a virtual experiment in which the ultimate behaviour of a plate girder is studied.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available