Bead on Plate Simulations

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• Bead on Plate Simulations
• Colin Elcoate - Frazer Nash Consultancy Ltd
• for British Energy Generation Ltd
• (on behalf of the Industry Management Committee)
• FEAT TUG 9th May 2002

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Bead on Plate Simulations

• Contents
• Background
• FEAT Models
• Moving torch
• Lumped approach
• Comparisons
• Problems encountered
• Further/Current Developments (2002/2003)
• Conclusion

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Bead on Plate Simulations

• Contents
• Background
• FEAT Models
• Moving torch
• Lumped approach
• Comparisons
• Problems encountered
• Further/Current Developments (2002/2003)
• Conclusion

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Bead on Plate Simulations

• Background
• Accurate prediction of residual stresses in
  repair welds
• Axisymmetric and 3D shell models (ABAQUS) did not
  give very good comparison with experiment
• Initial FEAT analyse by RMS under VORSAC
• Demonstrated excellent potential
• Work continued through IMC, BEGL and NPOWER

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Bead on Plate Simulations

• Contents
• Background
• FEAT Models
• Moving torch
• Lumped approach
• Comparisons
• Problems encountered
• Further/Current Developments (2002/2003)
• Conclusion

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Bead on Plate Simulations
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Bead on Plate Simulations
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Bead on Plate Simulations

• Contents
• Background
• FEAT Models
• Moving torch
• Lumped approach
• Comparisons
• Problems encountered
• Further/Current Developments (2002/2003)
• Conclusion

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Bead on Plate Simulations

• Moving Torch
• Ellipsoidal distribution
• 70 efficiency - ratio of heat entering the work
  piece to the electrical heat input (typically
  66-85)
• Sensible predicted fusion boundary

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Bead on Plate Simulations
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Bead on Plate Simulations

• Contents
• Background
• FEAT Models
• Moving torch
• Lumped approach
• Comparisons
• Problems encountered
• Further/Current Developments (2002/2003)
• Conclusion

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Bead on Plate Simulations

• Lumped Approach
• 70 efficiency - ratio of heat entering the work
  piece to the electrical heat input
• Heat deposition representative of moving torch -
  only changes in time and z (along the bead)
• Predicted fusion boundary deeper than equivalent
  moving torch simulation

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Bead on Plate Simulations
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Bead on Plate Simulations
Lumped model heat deposition normalised power
factor
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Bead on Plate Simulations
Lumped model non-dimensional transient heat
deposition
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Bead on Plate Simulations
Moving Torch
Lumped Approach
Comparison of fusion boundary at mid-length of
bead
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Bead on Plate Simulations
Comparison of fusion boundary at mid-length of
bead
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Bead on Plate Simulations
Macro-graph along the bead
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Bead on Plate Simulations

• Contents
• Background
• FEAT Models
• Moving torch
• Lumped approach
• Comparisons
• Problems encountered
• Further/Current Developments (2002/2003)
• Conclusion

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Bead on Plate Simulations

• Comparison
• Comparisons carried out between the FEAT moving
  torch and lumped approaches
• Comparison of the moving torch analysis against
  published numerical results (different material)
  gave good comparison of stress distribution

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Bead on Plate Simulations
Torch
Moving Torch
Lumped Approach
Comparison of parent plate top surface
longitudinal stress
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Bead on Plate Simulations
Torch
Moving Torch
Lumped Approach
Comparison of parent plate bottom surface
longitudinal stress
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Bead on Plate Simulations
Torch
Moving Torch
Lumped Approach
Comparison of parent plate top surface transverse
stress
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Bead on Plate Simulations
Torch
Moving Torch
Lumped Approach
Comparison of parent plate bottom surface
transverse stress
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Bead on Plate Simulations
Moving Torch
Lumped Approach
Comparison of longitudinal stress at mid-length
cross section
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Bead on Plate Simulations
Moving Torch
Lumped Approach
Comparison of longitudinal stress on symmetry
plane
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Bead on Plate Simulations
Moving Torch
Lumped Approach
Comparison of transverse stress at mid-length
cross section
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Bead on Plate Simulations
Moving Torch
Lumped Approach
Comparison of transverse stress on symmetry plane
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Bead on Plate Simulations
Stress comparison at 2mm below top plate surface
along longitudinal plate axis
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Bead on Plate Simulations
Stress comparison at 2mm above bottom plate
surface along longitudinal plate axis
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Bead on Plate Simulations

• Contents
• Background
• FEAT Models
• Moving torch
• Lumped approach
• Comparisons
• Problems encountered
• Further/Current Developments (2002/2003)
• Conclusion

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Bead on Plate Simulations

• Problems Encountered
• Annealing (molten strain)
• Plasticity algorithm robustness

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Bead on Plate Simulations

• Contents
• Background
• FEAT Models
• Moving torch
• Lumped approach
• Comparisons
• Problems encountered
• Further/Current Developments (2002/2003)
• Conclusion

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Bead on Plate Simulations

• Further/Current Developments
• NPOWER/BEGL funded repair weld simulation
• FEAT/ABAQUS hybrid
• ABAQUS 6.2 Annealing feature
• Include creep and reheat cracking
• Bead on plate simulations very good
• Repair weld ongoing (lumped)

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Bead on Plate Simulations

• Contents
• Background
• FEAT Models
• Moving torch
• Lumped approach
• Comparisons
• Problems encountered
• Further/Current Developments (2002/2003)
• Conclusion

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Bead on Plate Simulations

• Conclusions
• Work ongoing to provide BEGL with a robust
  simulation tool for repair welds
• Improved hardware and software provides
  manageable run times
• Hybrid approach currently adopted with FEAT doing
  all the hard work