Theory of Yarn Structure

By Prof. Dipayan Das   |   IIT Delhi
Learners enrolled: 227
This course deals with a system of theoretically derived inherent laws of structures and properties of yarns. Each module of this course is started with definitions, terminologies and fundamental relations. Then, the theoretical models are presented namely from the initial assumptions through the mathematical derivation to the final relations. Such theoretical results are mostly compared with the experimental ones. The topics in this course include basic characteristics of fibers and yarns; relation among yarn count, twist, and diameter; helical model of fibers in yarns; mass irregularity of yarns; radial fiber migration in yarns; yarn shrinkage due to washing; and tensile mechanics of yarns.

INTENDED AUDIENCE  : Interested students
PREREQUISITES : BE/BTech in Textile Technologyl
INDUSTRY SUPPORT : Trident, Arvind, Welspun
Course Status : Completed
Course Type : Elective
Duration : 12 weeks
Category :
  • Textile Engineering
Credit Points : 3
Level : Undergraduate
Start Date : 24 Jan 2022
End Date : 15 Apr 2022
Enrollment Ends : 07 Feb 2022
Exam Date : 24 Apr 2022 IST

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

Page Visits

Course layout

Week 1 : Fiber – The Building block of yarns
Week 2 : Basic characteristics of yarns
Week 3 : Relation among yarn count, twist, and diameter
Week 4 : Helical model of fibers in yarns
Week 5 : Mass irregularity of yarns
Week 6 : Radial fibre migration in yarns
Week 7 : Yarn shrinkage due to washing
Week 8 : Tensile mechanics of yarns - Part I
Week 9 : Tensile mechanics of yarns - Part II
Week 10 : Tensile mechanics of yarns - Part III
Week 11 : Tensile mechanics of yarns - Part IV
Week 12 : Strength-length relation in yarn

Books and references

B. Neckář and D. Das, Theory of Structure and Mechanics of Yarns, Woodhead Publishing India Pvt. Ltd., New Delhi, 2018

Instructor bio

Prof. Dipayan Das

IIT Delhi
Dr. Dipayan Das is currently working as Professor at the Department of Textile Technology of Indian Institute of Technology Delhi. He received PhD from Technical University of Liberec, Czech Republic in 2005. This was followed by a position as post-doc research associate in the NC State University, USA. He joined IIT Delhi as Assistant Professor in 2008. He served as Adjunct Assistant Professor at the Department of Textile Engineering,Chemistry & Science of NC State University from 2008 to 2009. At IIT Delhi, he was promoted to Associate Professor and Professor in 2012 and 2018, respectively. He has taught several courses, including Yarn Manufacturing, Textile Structures, Nonwoven Technology, Design of Experiments and Statistical Techniques, at undergraduate and postgraduate levels. His research interest lies in the areas of Textile Structures, Nonwovens, and Product and Process Optimization. He has published four books, two monographs, and over 130 research articles in scientific journals and conference proceedings. He has guided over 30 theses, leading to various degrees, including PhD and MTech. He is a recipient of the BIRAC-SRISTI GYTI Appreciation Award (2018), IIT Delhi Teaching Excellence Award (2017), and Kusuma Trust Outstanding Young Faculty Fellowship (2008-2013).

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 2022 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.


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 Madras .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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