Examination arrangement

Course content

Fatigue failure and fracture often occur in various branches of engineering being one of the main reasons of unexpected termination of anticipated service lives of mechanical components. This leads to unfortunate catastrophic structural failures resulting in loss of lives and in excessive costs. The theory behind fatigue and fracture mechanics enables the analysis of structural integrity of engineering components and helps preventing the occurrence of structural failure. Fatigue and fracture mechanics as a scientific discipline has enabled scientists and engineers to speak the same language when dealing with the design and manufacturing of mechanical components and structures.

This course deals with fundamental and technical issues associate with designing and maintaining structures that are subjected to static and cyclic mechanical loading. Students will be taught the principles of fatigue and fracture mechanics and methodologies to evaluate material’s resistance to these failures by mechanical testing, addressing the questions on how fatigue behavior is characterized, how failure due to fatigue and fracture is predicted, and ultimately how this behavior is linked to the microstructure of the material and also the design of the component. An introduction on key applications of fracture mechanics and fatigue design in industry including failure analysis, design against failure, fatigue life estimation and experimental procedures for damage detection will also be provided in the course.

Learning outcome

Knowledge:

• Knowledge of basic fatigue and fracture mechanics theories and their physical failure mechanisms.
• Understanding of the application of fatigue and fracture mechanics to specific engineering problems.
• Detailed knowledge of experimental and FE-based numerical tools for evaluating the failure due to fatigue and fracture in materials and structures.
• Methodology for designing against fatigue.

Skills:

• Capability to use traditional and numerical methods for designing mechanical components against fatigue.
• Capability to use crack-growth analysis for load bearing and fatigue life assessment of mechanical components containing cracks, crack-like defects and geometrical complexities (also known as notch).

General competence:

To be able to evaluate fatigue damage and resistance against fracture and to design machines and structures against fatigue and fracture failure and to predict the expected life of components in service.

Learning methods and activities

Lectures: Both presentations and blackboard are used in parallel for teaching. Some lectures can be performed "digitally". Teaching materials are provided through Blackboard. The purchase of textbooks is not necessary for the successful completion of this course though it is encouraged for additional learning. Self-made notes during the lectures are encouraged since the lectures include the material and discussion which are hardly available in textbooks.

FE modelling training: The students are taught the basic knowledge and operation of FE analysis, as well as how to use ABAQUS as the selected FE program, as an effective tool to analyze fracture and fatigue life.

Compulsory assignments

• Exercises
• FE project

Further on evaluation

Written exam (100%) forms the basis for evaluation in the course. The lectures and exercises are in English when students who do not speak Norwegian take the course. If the teaching is given in English, the examination papers will be given in English only. In this case the students also must reply in English. Non-programmable scientific calculators, which are not listed among the "specific basic calculators", and calculators having no access to the Internet can be allowed for the exam upon approval from the course coordinator.

Compulsory assignments: Exercises and FE project (see below). Compulsory activities from previous semesters may be approved by the department.

Exercises: Eight assignments will be given during the course. Seven approved of total eight assignments are required to qualify for the exam.

FE project: The FE project is in form of numerical modelling tasks based on the given lectures in the course and should be performed by the students individually and delivered in form of written report of the modelling process and presentation of results and most importantly discussions. The delivered reports will then be evaluated after the defined deadline. The submitted assignments after the defined deadline will not be graded and approved. Approval of FE project is required to qualify for the exam.

For a re-take of an examination, all assessments during the course must be re-taken. If there is a re-sit examination, the examination form may be changed from written to oral.

Recommended previous knowledge

The students must have access to a windows compatible laptop powerful enough to run CAE software packages.

Knowledge equivalent to TMM4100 Materials Technology and TMM4140 Mechanical behavior of materials. Previous knowledge in Finite Element analysis with commercial CAE software packages is an advantage.

Course materials

Main: N. Dowling " Mechanical Behavior of Materials", Pearson Prentice Hall, 2007 (or later). Optional: T. L. Anderson: Fracture Mechanics. Fundamentals and Applications, CRC Press, 2004. Ralph I. Stephens, Ali Fatemi, Robert R. Stephens, Henry O. Fuchs "Metal Fatigue in Engineering", 2nd Edition 2000 Wiley. S. Suresh, "Fatigue of Materials" (2d edition) Cambridge University Press, 1998. Radaj, Dieter, Vormwald, Michael "Advanced Methods of Fatigue Assessment", Springer 2013

Credit reductions