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Sequentially Cold Forming Simulation of
Complex Shaped Heavy Plates
23.04.2013 © 2013 UNIVERSITY ROSTOCK | FACULTY OF MECHANICAL ENGINEERING AND MARINE TECHNOLOGY
Authors:
Steffen Garke, Ralf Tschullik, Patrick Kaeding
(Chair of Ship Structures – University of Rostock)
Agenda
• University of Rostock
• Chair of Ship Structure
• Problem Definition
• Process Analysis
• Process Simulation
• Results
• Conclusion
• Prospects
• Question and Answers
• References
2 © 2013 UNIVERSITY ROSTOCK | FACULTY OF MECHANICAL ENGINEERING AND MARINE TECHNOLOGY 23.04.2013
funded by:
3 © 2013 UNIVERSITY ROSTOCK | FACULTY OF MECHANICAL ENGINEERING AND MARINE TECHNOLOGY 23.04.2013
funded by:
University of Rostock
Facts:
• oldest university in the Baltic Sea region (founded 1419)
• 9 faculties (+ one central interdisciplinary faculty)
• 5.000 employees + 15.000 students
Figure 2: Research – Third-party funds (in million Euro) (1) Figure 1: Students – distribution to the faculties (1)
4 © 2013 UNIVERSITY ROSTOCK | FACULTY OF MECHANICAL ENGINEERING AND MARINE TECHNOLOGY 23.04.2013
funded by:
Chair of Ship Structures
Main tasks:
• numerical methods for ship and offshore
structural design
• marine steel constructions
• material science for ship and offshore structures
• production and outfitting
Research Project:
• GrundVorm (Numerical Study for a New Thick
Plate Forming Process)
• heavy plates multidimensional curved
• variable in thickness
• superposition of forming and rolling
5 © 2013 UNIVERSITY ROSTOCK | FACULTY OF MECHANICAL ENGINEERING AND MARINE TECHNOLOGY 23.04.2013
funded by:
Problem Definition
• heavy steel plates
• thickness: 4 mm – 100 mm
• marine technology, wind turbines
• production quality requirements increase
• deformed manually
• optimized hull-forms, complex shaped plates
• one-of-a-kind productions
• flexible production process necessary
• time consuming
• several hundreds of steps
• machine and tool-changing necessary
• quality related to worker
Figure 3: flow dynamics around a bulb bow (2)
Figure 4: worker during forming process (3)
6 © 2013 UNIVERSITY ROSTOCK | FACULTY OF MECHANICAL ENGINEERING AND MARINE TECHNOLOGY 23.04.2013
funded by:
• enlargement of heavy plates applications
• e.g. offshore components
• repeating structures
• efficient and profitable manufacturing
automation of existing process Figure 5: rotor blade of an offshore wind turbine (4)
Needs:
• process-analysis
• physical understanding
• accurate simulations
Figure 6: forming-process (3)
Problem Definition - Purpose
7 © 2013 UNIVERSITY ROSTOCK | FACULTY OF MECHANICAL ENGINEERING AND MARINE TECHNOLOGY 23.04.2013
funded by:
Figure 7: fore ship bulb bow (3)
Gaussian curvature:
→ developable surface
K = k1
k2
=1
r1
1
r2
= 0
Figure 8: extracted plate (3)
here: K ≠ 0
Stretch Forming!
Process Analysis - Beginning
• exemplary plate
• part of an existing fore ship
• complex shaped
• not developable surface
• local material stretching necessary
8 © 2013 UNIVERSITY ROSTOCK | FACULTY OF MECHANICAL ENGINEERING AND MARINE TECHNOLOGY 23.04.2013
funded by:
Process Analysis - Workflow
Figure 9: workflow forming process (3)
• totally 1.477 steps
• experiment duration 3 days
• shape controlling
• laser scanning
Figure 10: shape control with templates (3)
automation without changing
process impossible!
9 © 2013 UNIVERSITY ROSTOCK | FACULTY OF MECHANICAL ENGINEERING AND MARINE TECHNOLOGY 23.04.2013
funded by:
Process Simulation
Figure 11: force-time diagram (3)
challenges:
• accurate simulation model
• smaller validation experiments
• scaled ship building press (1:4)
• one step deformation
• expected high computation time
• explicit solution (RADIOSS)
• solid elements (3 over plate thickness)
• real-time (1,7 seconds per stroke)
• unknown position of next tool contact → stop simulation after every stroke → save
element state → find next position → move and rotate tool → restart simulation → …
automated sequential calculation necessary!
10 © 2013 UNIVERSITY ROSTOCK | FACULTY OF MECHANICAL ENGINEERING AND MARINE TECHNOLOGY 23.04.2013
funded by:
• MATLAB® - Environment
• control forming process
• call HyperMesh (batch)
• call RADIOSS (batch)
• read results
• calculate tool position
Figure 13: work-flow Forming Tool (3)
Figure 12: predefined tool-contact-lines (3)
Process Simulation - Forming Tool
Results
11 © 2013 UNIVERSITY ROSTOCK | FACULTY OF MECHANICAL ENGINEERING AND MARINE TECHNOLOGY 23.04.2013
funded by:
• facts
• 94 forming steps to calculate
• nonlinear material behavior
• sensors (force-controlled-forming)
• contact formulations
• calculation - time → 18 days
• average time per step 4,5 hours
Figure 15: deformation overview (3) Figure 14: start-position (3)
12 © 2013 UNIVERSITY ROSTOCK | FACULTY OF MECHANICAL ENGINEERING AND MARINE TECHNOLOGY 23.04.2013
funded by:
Figure 16: plastic strain – step 37 of 94 (3)
Figure 17: comparison simulation and laser scan (3)
Results - Discussion 1
• Forming-Tool works
• all steps continuous calculated
• expected local permanent deformations
• global deformation follows reality
(comparison with laser scans)
• no quantitative comparison!
13 © 2013 UNIVERSITY ROSTOCK | FACULTY OF MECHANICAL ENGINEERING AND MARINE TECHNOLOGY 23.04.2013
funded by:
Figure 18: comparison simulation and laser scan - full (3)
• laser scan after 25% of forming process
• 300 forming steps in reality
• compressed to 94 simulation steps
Results - Discussion 2
Conclusion
14 © 2013 UNIVERSITY ROSTOCK | FACULTY OF MECHANICAL ENGINEERING AND MARINE TECHNOLOGY 23.04.2013
funded by:
• detailed view inside of forming processes of complex shaped heavy plates
• large documentation of an exemplary plate-forming
• validation experiments
• simulation models
• RADIOSS based Forming-Tool
• basis for an automated forming process
Prospects
15 © 2013 UNIVERSITY ROSTOCK | FACULTY OF MECHANICAL ENGINEERING AND MARINE TECHNOLOGY 23.04.2013
funded by:
• reducing calculation time
• simulation of the whole process
• detailed result comparison
• update the Forming-Tool
• avoid third-party programs
• optimize the tool positioning (→ similar to contact search algorithm)
• reduce to main forming steps
• repeat experiment with calculated data
Questions and Answers
16 © 2013 UNIVERSITY ROSTOCK | FACULTY OF MECHANICAL ENGINEERING AND MARINE TECHNOLOGY 23.04.2013
funded by:
Thank you for your attention!
funded by the ministry of economics, labour and tourism of the German state of Mecklenburg-Vorpommern
References
(1) Kanzler (Head of Administration and Finance/Member of the Board) Support Position
Controlling, “The University in Figures”, Rostock, 2012.
(2) Lindner, H., ”Verifizierung und Validierung von numerischen Schleppversuchen mit
einem frei trimm- und tauchenden Schiffsmodell”, diploma thesis, Faculty of
Mechanical Engineering and Marine Technology – Ship Design, University of Rostock,
Rostock, 2012.
(3) Garke, S., “Numerische Untersuchungen beim Reckprozess von Grobblechen”,
diploma thesis, Faculty of Mechanical and Marine Technology – Ship Structures,
University of Rostock, Rostock, 2012.
(4) Tschullik, R., “Verfahrensentwicklung zur 3D Verformung von Grobblech”, Europatag,
2010.
17 © 2013 UNIVERSITY ROSTOCK | FACULTY OF MECHANICAL ENGINEERING AND MARINE TECHNOLOGY 23.04.2013
funded by: