Sequentially Cold Forming Simulation of Complex Shaped Heavy Plates

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:


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)


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


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)


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


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


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!


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!


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


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)


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!


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


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


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


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.


funded by: