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SD2420 Advanced design of welded structures 6.0 credits

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Headings with content from the Course syllabus SD2420 (Spring 2022–) are denoted with an asterisk ( )

Content and learning outcomes

Course contents

This course discuss different advanced methods for fatigue design of welded structures; nominal stress method, hot spot (geometric/structural) stress method, effective notch stress method and applied linear elastic fracture mechanics (LEFM). Infleunce of different factors that effect the fatigue life and breakdown is discussed, such as; stress concentrations, weld defects, welding residual stresses, multiaxial stress states, etc. Different post weld improvement techniques in order to increase the weld quality and the fatigue strength of welded structures is duscussed. Different weld class systems in order to assure the weld quality of welded jonits in the design and  during production is discussed and compared. Different design codes, guidelines for practice and reccomendations for welded jonits are discussed, e.g. IIW:s "recommendations for fatigue design of welded jonits and components". Evaluation and fatigue design of welded structures using FEM is treated regarding; boundary conditions, accuracy, non-linearity, sub-modelling techniques, 3D effects. Different state-of-the art applied fracture mechanical softwares for prediction of the fatigue life of welded jonits is presented, discussed and utilized.

Intended learning outcomes

In order to guarantee the strength of a welded structures different design codes have been developed during the last 30 years and have been applicable within the manufacturing industry with low accuracy and precision. As the finite element analysis is nowadays a widley used tool new developed design codes are applicable with better accuracy and precision. After the course the student should be able to:

  1. Chose method for fatigue life assessment with reasonable accuracy for different types of welded jonits and structures.
  2. Understand the effects of welding residual stress on the strucutral integrity.
  3. Understand the influence of different types of weld defects and discontinuities on the the fatigue strength of welded jonits.
  4. Choose appropriate analysis method and perform fatigue life assessment of complex welded structures.
  5. Chose relevant post weld improvment techniques for different welded applications.
  6. Use weld quality systems. 

Course disposition

No information inserted

Literature and preparations

Specific prerequisites

FEM, Linear elastic fracture mechanics (LEFM) and basic knowledge in solid mechanics, material mechanics and fatigue.

English B / English 6

Recommended prerequisites

No information inserted


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Examination and completion

If the course is discontinued, students may request to be examined during the following two academic years.

Grading scale

P, F


  • BER1 - Assignment 1, 2.0 credits, grading scale: P, F
  • BER2 - Assignment 2, 2.0 credits, grading scale: P, F
  • LAB1 - Labs and assignments, 2.0 credits, grading scale: P, F

Based on recommendation from KTH’s coordinator for disabilities, the examiner will decide how to adapt an examination for students with documented disability.

The examiner may apply another examination format when re-examining individual students.

Grading scale P/F

Other requirements for final grade

LAB1 - 3 computerlabs/excercises on fatigue design and FEM. Examination by handing in lab report.

BER1 - 1 extensive home assignment on fatigue design of a welded structure. Examination; handed in report.

BER2 - 1 extensive home assignment and case study on fatigue design of a welded structure. Examination; handed in report.

Opportunity to complete the requirements via supplementary examination

No information inserted

Opportunity to raise an approved grade via renewed examination

No information inserted


Ethical approach

  • All members of a group are responsible for the group's work.
  • In any assessment, every student shall honestly disclose any help received and sources used.
  • In an oral assessment, every student shall be able to present and answer questions about the entire assignment and solution.

Further information

Course web

Further information about the course can be found on the Course web at the link below. Information on the Course web will later be moved to this site.

Course web SD2420

Offered by

Main field of study

This course does not belong to any Main field of study.

Education cycle

Second cycle

Add-on studies

No information inserted


Zuheir Barsoum,