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.
SD2420 Advanced design of welded structures 6.0 credits

Information per course offering
Information for Autumn 2025 Start 25 Aug 2025 programme students
- Course location
KTH Campus
- Duration
- 25 Aug 2025 - 24 Oct 2025
- Periods
- P1 (6.0 hp)
- Pace of study
50%
- Application code
51524
- Form of study
Normal Daytime
- Language of instruction
English
- Course memo
- Course memo is not published
- Number of places
Places are not limited
- Target group
Open for: All Master of Science in Engineering in 3rd year, all Master programmes as long as it can be included in your programme.
- Planned modular schedule
- [object Object]
- Schedule
- Schedule is not published
- Part of programme
Contact
Course syllabus as PDF
Please note: all information from the Course syllabus is available on this page in an accessible format.
Course syllabus SD2420 (Spring 2022–)Content and learning outcomes
Course contents
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:
- Chose method for fatigue life assessment with reasonable accuracy for different types of welded jonits and structures.
- Understand the effects of welding residual stress on the strucutral integrity.
- Understand the influence of different types of weld defects and discontinuities on the the fatigue strength of welded jonits.
- Choose appropriate analysis method and perform fatigue life assessment of complex welded structures.
- Chose relevant post weld improvment techniques for different welded applications.
- Use weld quality systems.
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
Literature
Examination and completion
If the course is discontinued, students may request to be examined during the following two academic years.
Grading scale
Examination
- 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.
Examiner
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.