How is plastic behaviour in metals simulated and used in practical engineering applications?

What are potential difficulties and challenges in modelling plasticity problems using FE software?

What are the potential errors and limitations of the FE plasticity solutions?

This course gives you practical advice with a minimum of theory.

Metals Material Modelling: Plasticity

The course covers plasticity theories that are widely used to analyse practical engineering applications in metals. Mathematical formulations and equations are intentionally kept to a minimum. Emphasis will be placed on how engineering design incorporates these theories and how the FE method models plasticity. Difficulties encountered by both the FE user and the FE software in modelling plasticity will be highlighted using many examples to demonstrate plastic behaviour and how to assess the accuracy of the FE solutions.

Topics covered include; introducing plasticity, plasticity formulations, computational modelling (dividing the load, iterations, pseudo-time etc), plasticity in engineering design, examples (isotropic, kinematic, multiaxial), and more.

What will you learn?

How plastic behaviour in metals is modelled using FE software
Limitations of FE plasticity modelling
Common FE simulation pitfalls and how to avoid them

Who should attend?

Engineers looking for an insight into the background theory of plasticity
Anyone looking to simulation metal plasticity using FEA
Experienced engineers who need to brush up their plasticity theory

The course is completely code independent.

This is a 3-session online training course, with each session lasting for approximately 2 hours, depending on homework submissions, questions & discussions.

You can attend the sessions live, and/or stream on demand. When you register you will get access to a dedicated course forum where you can contact the tutor with questions, submit homework, download pdfs of course notes and access all session recordings. To get the most out of the course, participation in forum discussions is encouraged.

Questions? Contact us on e-learning@nafems.org

Course Program

Session 1

Introduction to Plasticity

Metals and ductility
Elastic stress-strain relationships
Elastic-plastic behaviour
Laboratory uniaxial tests and stress-strain curves
Yield stress and proof stress
Modelling Nonlinear Material Behaviour

Review of Plasticity formulations

True stress and true strain
Deviatoric and hydrostatic Stress
Yield criteria
Von Mises Yield Surface- A geometric volume
Post-yield behaviour and work hardening
Plastic flow behaviour
Other yield criteria used in FE software
Reversed loading and Hysteresis Loop
Cyclic Loading, shakedown and Ratchetting

Self-test questions (optional homework)- Questions to reinforce the topics covered in the lectures

Session 2

Computational Modelling of Plasticity

Dividing the load into small chunks (increments)
Iterations- checking all is well before proceeding to the next increment
A simple plasticity algorithm
How does the algorithm become more complicated?
Is plasticity really time-independent?
What is pseudo-time?
What happens at very high temperatures?
Can plastic collapse (too much plasticity) be modelled?

Solutions to self-test questions (Full solutions highlighting the key aspects)

Plasticity in Engineering design

Can plasticity be useful in engineering?
Partially controlled plasticity (autofrettage)
Residual stresses
Shot peening
Plasticity around cracks
Plasticity in beams and thick cylinders

More Self-test questions (optional homework)

Session 3

Modelling Plasticity Using FE software

Is it difficult to model plasticity using FE software?
What plasticity data should be input in the FE code?
What are the limitations of FE plasticity models?
What happens after the material reaches the Ultimate Tensile Stress?
What can go wrong in the FE simulation?

Solutions to more self-test questions

FE Plasticity Examples

Isotropic hardening example
Kinematic hardening example
Multiaxial cylinder example
Cyclic loading example
Rigid punch example

Summary of key points, tips and guidelines

Feedback from former e-Learning students:

"Super! Doesn't get better than this. Good idea to start having e-Learning courses."
R.P.
"I'm really happy not to pay a big fraction of my annual training budget to airlines and hotels. A BIG plus to e-learning."
V.G.

PSE

PSE Competencies addressed by this training course

ID	Competence Statement
PLASkn1	For a beam under pure bending sketch the developing stress distribution from first yield, to collapse.
PLASkn2	For a simple steel thick cylinder or sphere under internal pressure, state the location of first yield.
PLASkn7	Sketch a stress-strain curve for an elastic-perfectly plastic and bi-linear hardening material showing elastic and plastic moduli.
PLASco1	Discuss salient features of the inelastic response of metals.
PLASco2	Explain the terms Isotropic Hardening, Kinematic Hardening and Rate Independency.
PLASco3	Discuss the role of the Hydrostatic and Deviatoric Stress Components in yield criteria for isotropic, polycrystalline solids.
PLASco7	Explain the phenomenon of Shakedown and define the term Shakedown Load.
PLASco8	Contrast the terms Ratchetting and Low Cycle Fatigue.
PLASco11	Explain how plastic effects in a Finite Element system are commonly handled as a series of incremental iterative linear analyses
PLASco12	Explain, in general terms, the function of the Mises Flow Rule or Prandtl-Reuss Equations, used in a finite element solver.
PLASco13	Outline how the cumulative and incremental displacements, total strains, elastic strains, elastic stresses and plastic strains are related in the finite element method
PLASco14	Illustrate typical examples of Local Plastic Deformation and Gross Plastic Deformation.
PLASco16	Explain the significance of a Hysteresis Loop in a load/deflection test.
PLASco23	Describe the Bauschinger Effect.
PLASco27	Explain the process of Stress Redistribution.
PLASco28	Describe the process and common purpose of Autofrettage.
PLASap4	Use FEA to illustrate Shakedown for a range of components/structures and actions.
PLASap5	Use FEA to determine the presence of ratchetting for a range of components and actions.
PLASap7	Using standard material data, derive a true stress vs true strain curve to be used for nonlinear analysis.
PLASsy2	Plan a series of simple benchmarks in support of a more complex plasticity analysis.
PLASsy4	Prepare an analysis specification for a nonlinear material analysis, including modelling strategy, highlighting any assumptions relating to geometry, loads, boundary conditions...
PLASev1	Select appropriate solution schemes for non-linear material problems.
PLASev4	Assess the significance of simplifying geometry, material models, mass, loads or boundary conditions, on a non linear material analysis.

Three-Session Online Training Course

2 hours per session
PDH Credits - 6

Attend the live sessions, or view the recordings at your convenience.

Not Available to Attend this Time?

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Please click here to view the FAQ section, or if you need to contact NAFEMS about this course.

Engineering Board PDH Credits

*It is your individual responsibility to check whether these e-learning courses satisfy the criteria set-out by your state engineering board. NAFEMS does not guarantee that your individual board will accept these courses for PDH credit, but we believe that the courses comply with regulations in most US states (except Florida, North Carolina, Louisiana, and New York, where providors are required to be pre-approved)

Special Note(s):

Telephony surcharges may apply for attendees who are located outside of North America, South America and Europe. These surcharges are related to individuals who join the audio portion of the web-meeting by calling in to the provided toll/toll-free teleconferencing lines. We have made a VoIP option available so anyone attending the class can join using a headset (headphones) connected to the computer. There is no associated surcharge to utilize the VoIP option, and is actually encouraged to ensure NAFEMS is able to keep the e-Learning course fees as low as possible. Please send an email to the e-Learning coordinator (e-learning @ nafems.org ) to determine if these surcharges may apply to your specific case.

Just as with a live face-to-face training course, each registration only covers one person. If you plan to register a large group (10+), please send an email to e-learning @ nafems.org in advance for group discounts.

For NAFEMS cancellation and transfer policy, click here.