| CODE | MME4004 | ||||||||||||
| TITLE | Mechanics of Material Failure | ||||||||||||
| UM LEVEL | 04 - Years 4, 5 in Modular UG or PG Cert Course | ||||||||||||
| ECTS CREDITS | 5 | ||||||||||||
| DEPARTMENT | Metallurgy and Materials Engineering | ||||||||||||
| DESCRIPTION | The study-unit presents the basic terminology and parameters which dictate the material response to deformation and ultimately the resistance to ductile or brittle failure. A detailed analysis of how different crystallographic structures affect the mechanical properties is given. This is followed by a description of the principal plastic deformation mechanisms such as slip, twinning and dislocation motion and interaction. Principles of ductile and brittle fracture are then introduced. These are correlated with microscopic features observable during fractographic studies. The classical theory of fracture mechanics is presented, including the effect of stress concentrations and the relevant mathematical stress models. Griffith's and Irwin's energetic and stress intensity approach is explained. Local crack tip plasticity and the concept of fracture toughness is also explained. These are related to material aspects including permanent slip bands, work hardening and surface treatments. Fatigue failure from initiation to progression, and fatigue life estimation methods are discussed in some depth. The variables affecting fatigue behaviour and material susceptibility are presented. Testing techniques are also explained. Furthermore, methods used for the technical analysis of material and component failures are discussed together with practical tools such as non destructive techniques commonly employed on site. Finally, high temperature deformation and material failure - creep is discussed. The different stages are outlines and experimental methods for life prediction are explained. Study-Unit Aims: To provide a comprehensive introduction to material deformation and failure underlying the differences in material response to static and dynamic loading at low and relatively high temperatures (exceeding a third of materials melting temperature). The study-unit aims to provide the students both familiarity with material failure modes and the necessary tools to understand flaws in material and product design. This includes experimental and mathematical models needed to predict the life of a material under load. Furthermore, the study-unit is designed to enable students to understand the effect of manufacturing processing, material processing routes and environmental operating conditions on failure of materials. Learning Outcomes: 1. Knowledge & Understanding: By the end of the study-unit the student will be able to: 1. understand and describe the important material characteristics which dictate its elastic, plastic deformation and its ultimate failure mode; 2. comprehend the most important concepts related to fracture mechanics and particularly LEFM; 3. understand the principles of crack growth and propagation; 4. explain the effects of increased temperature, in addition to load, on the deformation of materials - particularly on the movement of dislocations; 5. understand the basic material fatigue mechanisms. 2. Skills: By the end of the study-unit the student will be able to: 1. explain and predict the behaviour of a material depending on its basic characteristics, s uch as crystal structure, bonding type, texture etc; 2. calculate the life of a material under multiple/complex and variable stresses; 3. read creep deformation mechanism-maps for high temperature application of materials; 4. design tests for the evaluation of creep and fatigue resistance; 5. recognise failure types and use relevant techniques to determine cause of failure; 6. select suitable non-destructive testing techniques for quality control and failure preventi on. Main Text/s and any supplementary readings: Main Texts: [1] Physical Metallurgy Principles - R. Abbaschian, L. Abbaschian, R. Ree d-Hill (Nelson Engineering; 4th edition). [2] Principles of Fracture Mechanics - R. J. Sanford (Prentice Hall, 2003). Supplementary Readings: [3] Fatigue Testing and Analysis: Theory and Practice - Y. Lee, J. Pan, R. Hathaway, M. Barkey (Elsevier Butterworth-Heinemann, 2004). [4] Problems of fracture mechanics and fatigue: a solution guide - E. E. G doutos, C. A. Rodopoulos, J. R. Yates, (Kluwer Academic, 2003). [5] The Theory of Materials Failure, R.M. Christensen(Oxford University, 2016) (Submitted for acquisition). |
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| STUDY-UNIT TYPE | Lecture, Independent Study & Tutorial | ||||||||||||
| METHOD OF ASSESSMENT |
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| LECTURER/S | Stephen Abela |
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The University makes every effort to ensure that the published Courses Plans, Programmes of Study and Study-Unit information are complete and up-to-date at the time of publication. The University reserves the right to make changes in case errors are detected after publication.
The availability of optional units may be subject to timetabling constraints. Units not attracting a sufficient number of registrations may be withdrawn without notice. It should be noted that all the information in the description above applies to study-units available during the academic year 2024/5. It may be subject to change in subsequent years. |
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