Until recently, most finite element analysis (FEA) applications undertaken by design engineers were limited to linear analysis which provides an acceptable approximation of real-life characteristics for most problems. However, occasionally more challenging problems arise that call for a nonlinear approach. In this webinar, you will hear about real-world nonlinear applications and case studies associated with Comsol’s and MSC Software’s customers. Viewers of this webinar will learn: – How nonlinearities in engineering systems arise from several sources including: – Material properties including multi-physics behavior – Geometry variations that involve large deformations and strains – Boundary conditions that could be continuously changing affecting the response

1. Real World
Nonlinear Mechanical
Applications

2. Before We Start
This webinar will be available afterwards at
designworldonline.com & email
Q&A at the end of the presentation
Hashtag for this webinar: #DWwebinar

3. Moderator
Presenters
Laura Carrabine
David Kan
Srinivas Reddy
Design World
COMSOL
MSC Software

4. Real World Nonlinear Mechanical
Applications
Srinivas Reddy
February 29, 2012

5. Product Development Challenges
Can I build it?
Can I test it?
Is it durable?
Will it perform to spec?
Is it crashworthy?
Will it fail?
Is it safe?
Why did it fail?

6. CAE to Improve Product Performance
Sports equipment
Brake disk
Shearing/Tearing
Seal analysis
Bolt Loading
Pipe impact

7. CAE to Optimize Manufacturing Processes
Superplastic Forming
Riveting
Glass Forming
Forming
Cutting
Extrusion

8. Nature is Nonlinear
F
Load
Linear
Behavior
Nonlinear
Behavior
F
u
u
Displacement
s
Stress
Linear
Behavior
Nonlinear
Behavior
F
F
Yield Pt.
Strain
e

9. Sources of Nonlinearities
• Materials
o Metals, plastics, elastomers, powder metals,
shape memory
• Deformation
o Buckling, folding
• Boundary conditions and loads
o Contact, loads changing with deformation
• Multi-physics
o Temperature effects, electromagnetics

10. Challenges of Nonlinear Analysis
• Material modeling
• Large deformation,
distortions and rotations
• Contact
• Performance
• Robustness

11. Material Modeling
•
•
•
•
•
•
•
•
•
•
Metals
Plastics
Rubbers
Shape memory alloys
Composites
Glass
Concrete
Powder materials
Other non-metallic materials
Customizable behavior
Aluminum Can Pull
Tab
Plastic Bottle
Composite Materials
Rubber Tire with
Metal Rims

12. Material Failure
• Metals
o Ductile damage
• Elastomers
o Material weakening
• Composites
Crack Propagation
Fatigue crack growth
o Delamination
• Crack propagation
• Concrete
o Brittle failure, crushing
Gear failure
Delamination

13. Extreme Deformations
• Element formulations
• Appropriate stress/strain
measures
• Automatic local remeshing
o Mesh refining in high stress/strain
regions
• Automatic global remeshing
o Recreate a new mesh for the
entire part

14. Contact
• General large sliding
contact with friction
• Intuitive and easy set up
• Automatic contact
detection
• Remeshing
• Multi-physics

15. Performance
• Efficient solvers
• Parallel processing
o Excellent scaling
o Shared and distributed memory
~75k Degrees of Freedom
• Domain decomposition method
o Linear scaling
o Benefit from networked desktop systems
o Solver large models
• Better use of hardware
o GPU
MPI
MPI
MPI

16. Case Study: Column Shifter Boot
•
•
•
•
Business:
Automotive supplier
Challenge:
Accelerate the boot development to
satisfy the requirements of OEMs by
evaluating more design variants in less
time
Solution:
Design variants are studied with Marc to
predict the tear areas. For some design
variants the analysis results are verified
with tests
Value:
A boot design that meets the OEMs
requirement was found in less time at
less cost
17

17. Case Study
• Business:
Leading producer of aluminum for
engineered products
•
Challenge:
Avoiding tensile & compressive instability
in formed parts
•
Solution:
Iterative Blank Design using Inverse
Method with Marc
•
Value:
Accurate & efficient prediction of proper
designs for forming operation in less
time
18

18. Summary
• Nonlinear analysis challenges
o
o
o
o
Materials,
Large deformations and distortions
Contact and boundary conditions
Coupling
• Technologies
o
o
o
o
o
Materials models,
Contact modeling ease
Physics simulation
Automatic remeshing
Performance

19. Nonlinear Mechanics in COMSOL
A Multiphysics Perspective
David Kan
COMSOL, Inc.
February 29, 2012

20. The Multiphysics Approach

21. Structural Mechanics Branch

22. Sources of Mechanical Nonlinearity
Geometry
Materials
s
st
Contact
e

23. Geometric Nonlinearity
Small displacement
theory
Green-Lagrange strains

24. Nonlinear Constitutive Laws
s
s
e
Hyperelastic constitutive law
•
•
Rubber
Biological tissues
e
Elasto-plastic constitutive law
•
•
•
Metals
Plastics
Soils and concrete in compression

25. Hyperelastic Materials
Hyperelastic constitutive laws are defined
by the strain energy density, Ws
•
•
•
Neo-Hookean
Mooney-Rivlin
Murnaghan
s
e

26. Elasto-plastic Materials
Elasto-plastic materials are defined by two mechanical
behaviors: elastic and plastic
Nonlinear constitutive laws are defined above the yield
stress
In the plastic regime, there are irreversible strains
s
sy
el
e

27. Contact
Destination
Source
How about
Multiphysics?

28. The Metelli Experience
Hyperelastic material law
Nonlinear geometry
Contact everywhere
Multiphysics

29. Multiphysics and Mechanics
• Creep
• Predefined couplings
o
o
o
o
o
Piezoelectric effects
Acoustic-Structure Interaction
Thermal-Electric-Structural Interaction
Fluid-Structure Interaction
Thermal-Structural Interaction
• General couplings

30. Thank You!

31. Questions?
COMSOL
Design World
Laura Carrabine
lcarrabine@wtwhmedia.com
Phone: 440.234.4531
Twitter: @wtwh_laurac
David Kan
david.kan@comsol.com
Phone: 310.441.4800
Twitter: @COMSOL_Inc
MSC Software
Srinivas Reddy
srinivas.reddy@mscsoftware.com
Phone: 847.776.6740

32. Thank You
 This webinar will be available at designworldonline.com & email
 Tweet with hashtag #DWwebinar
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