Finite element modeling of welding processes

By Prof. Swarup Bag | IIT Guwahati

Learners enrolled: 825

The welding process involves complex interaction of several mechanisms. The fundamental understanding relied on basic mechanisms such as heat transfer and/or fluid flow, and associated distortion and residual stress generation including the effect of metallurgical transformation for a welding process is the focus of this course. It helps to develop the numerical model, and makes the foundation for analysis and experimentation for the process. The development of computational models for welding process relies on mathematical expression of the governing mechanism. It helps to design relevant experiments and drives to find the data to be obtained. Mutual understanding between numerical and experimental results leads to better insight of the welding processes that impact on the improvement of existing process and directs to the development of new process. This course emphasized on the development of finite element based numerical model of both fusion and solid state welding processes. The development of FE-based model is presented in a simplified way to understand the subject at elementary level. The broad impact is that the students will be able to develop FE-based heat transfer, fluid flow and stress analysis model of welding process using standard commercial package. However, this course does not intend to cover the learning of the commercial software.

INTENDED AUDIENCE : Bachelor/Master/PhD students having background in Mechanical/Material Science/Metallurgical engineering/ Production Engineering/Manufacturing Technology The faculty of different institutes can attend this course as a part of FDP.

PREREQUISITES : None

INDUSTRIES SUPPORT : None

Summary

Course Status :	Completed
Course Type :	Elective
Language for course content :	English
Duration :	12 weeks
Category :	Mechanical Engineering Advanced Mechanics Manufacturing Processes and Technology Computational Mechanics Materials Joining
Credit Points :	3
Level :	Undergraduate/Postgraduate
Start Date :	18 Jan 2021
End Date :	09 Apr 2021
Enrollment Ends :	01 Feb 2021
Exam Date :	24 Apr 2021 IST

Note: This exam date is subject to change based on seat availability. You can check final exam date on your hall ticket.

Page Visits

Course layout

Week 1-2:Introduction to welding processes
Classification, fusion welding, brazing and soldering, solid state welding processes, advanced welding processes, wire additive manufacturing processes

Week 3-4: Fundamentals of finite element (FE) method
Elastic stress Analysis, Weighted residue technique, Material non-linearity, Heat conduction, Fluid flow, Structure of a FE model, Steps of a FE model,
Introduction FE solver, X-FEM and other interface tracking methods

Week 5: Heat source model in conduction mode welding processes
Representation of heat source, Surface heat source model, Volumetric heat source model, Heat source model for solid state welding, Heat source model for keyhole mode laser and electron beam welding processes

Week 6-7:Application of FEM to model welding processes
Fusion welding: laser, arc, electron beam and resistance spot Solid state welding: Friction, FSW and hybrid FSW Representation of welding processes by governing equations and boundary conditions, Incorporation of heat source, Difference between linear and spot welding, FE formulation, Incorporation of temperature dependent properties, Incorporation of latent heat of melting and solidifications
Demonstration of thermal model development using commercial software

Week 8:FE-based fluid flow model in fusion welding processes
Surface active elements and fluid flow, Allied welding processes, Governing equations and boundary conditions, FE formulation, Solution strategy, Prediction of free surface profile

Week 9:FE-based elastic-plastic stress model of welding processes

Yield criteria, Hardening rule, Flow rule, Material models, FE formulation, Prediction of residual stress and distortion, Solution strategy, Incorporation of phase transformation effect
Demonstration of thermo-mechanical model development using commercial software

Week 10:FE model of metal transfer in welding
Fundamentals of metal transfer in arc welding, FE-based modelling approaches

Week 11: FE model of non-Fourier heat conduction
Ultra short pulse laser welding, Heating of nano-film, lattice distortion

Week 12:FE model of wire-additive manufacturing processes
Fundamentals of wire additive manufacturing processes, Modelling approaches of additive manufacturing, FE formulation, Solution strategy

Books and references

1. S Kalpakjian and S R Schmid: Manufacturing Engineering and Technology, 7th Ed., Pearson, 2018.

2. O P Gupta, Finite and Boundary Element Methods in Engineering, 1st Edition, Oxford & IBH Publishing, 1999.

3. O C Zienkiewicz, The Finite Element Method, 4th Edition, Tata McGraw Hill, 1991.

4. J N Reddy: An Introduction to the Finite Element Method, 3rd Eds., Tata McGraw Hill, 2006.

5. J. A. Goldak and A. Mehdi, Computational Welding Mechanics, Springer, NY, 2005.

6. M-K Besharati-Givi and P. Asadi: Advances in Friction-Stir Welding and Processing, Woodhead Publishing Limited, 2014

7. J. Norrish: Advanced Welding Processes, Woodhead publishing, 2006

8. C Lakshmana Rao and Abhijit P Deshpande: Modelling of Engineering Materials, Ane Books Pvt. Ltd., New Delhi, India, 2010.

9. S. Bag and A. De: Computational models for GTA and laser welding processes, Lap-Lambert Academic Publishing Co. Ltd., Germany, ISBN 978-3-659-42994-1, 2013.

Instructor bio

Prof. Swarup Bag

IIT Guwahati

The broad area of instructor is teaching and research interest of materials and manufacturing processes through computational models using finite element method and experiments. The instructor completed his Ph.D on “Development of bi-directional heat transfer and fluid flow model for reliable design of GTA and laser welding processes” from Indian Institute of Technology Bombay. Later he has worked at the Center for Material Forming (CEMEF), MINES Paris Tech, France in Metallurgy, Structure and Rheology (MSR) group. Soon after post-doctoral research experience, he joined in the Department of Mechanical Engineering, Indian Institute of Technology Guwahati as a faculty member. His primary area of research is fundamental process modeling of welding and joining technologies, optimization of manufacturing processes and recrystallization in metal forming processes. Dr. Bag has published about 56 journal papers, 45 Conference papers, and 18 book chapters related to welding and joining processes. He is the author of the book ‘Computational models for GTA and laser welding processes’ and recipient of ‘Royal Arc Award 2009’ from Indian Institute of Welding for the best PhD thesis in welding. The instructor is involved in teaching the subjects like ‘Physics of Manufacturing Processes’, ‘Engineering Materials’, ‘Advanced Welding Processes’, ‘Mechanical Behavior of Materials’, ‘Solidification Processes’ and ‘Manufacturing Technology’ at IIT Guwahati. The subjects broadly covers the fundamentals of manufacturing processes, mechanical metallurgy, theory of plasticity, heat transfer in manufacturing processes, crystallography, dislocation mechanism, phase transformation and solidification.

Course certificate

The course is free to enroll and learn from. But if you want a certificate, you have to register and write the proctored exam conducted by us in person at any of the designated exam centres.
The exam is optional for a fee of Rs 1000/- (Rupees one thousand only).
Date and Time of Exams: 24 April 2021 Morning session 9am to 12 noon; Afternoon Session 2pm to 5pm.
Registration url: Announcements will be made when the registration form is open for registrations.
The online registration form has to be filled and the certification exam fee needs to be paid. More details will be made available when the exam registration form is published. If there are any changes, it will be mentioned then.
Please check the form for more details on the cities where the exams will be held, the conditions you agree to when you fill the form etc.

CRITERIA TO GET A CERTIFICATE

Average assignment score = 25% of average of best 8 assignments out of the total 12 assignments given in the course.
Exam score = 75% of the proctored certification exam score out of 100

Final score = Average assignment score + Exam score

YOU WILL BE ELIGIBLE FOR A CERTIFICATE ONLY IF AVERAGE ASSIGNMENT SCORE >=10/25 AND EXAM SCORE >= 30/75. If one of the 2 criteria is not met, you will not get the certificate even if the Final score >= 40/100.

Certificate will have your name, photograph and the score in the final exam with the breakup.It will have the logos of NPTEL and IIT Guwahati .It will be e-verifiable at nptel.ac.in/noc.

Only the e-certificate will be made available. Hard copies will not be dispatched.

Once again, thanks for your interest in our online courses and certification. Happy learning.

- NPTEL team

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