When designing a machine or structure, in order to ensure its structural integrity, it is necessary to assume a crack generated during in-service and the initial defect in the structure material. In the case flaw is detected during operation, it is necessary to assess the integrity of the machines and structures by fracture mechanics methods. After reviewing the basics of fracture mechanics in this course, structural integrity assessment methods used in various engineering fields will be introduced . In the course, students will learn, for example, stress intensity factor, the crack tip plastic zone, fracture toughness, fracture resistance, Dugdale model, J integral, failure assessment diagram, fatigue cracks, stress corrosion cracking, safe life design, fail-safe design, damage tolerant design e.t.c..
In the first class, past failure accidents will be recalled and review the knowledge of engineering materials that engineers learned from the accidents. Starting with the second class, fracture mechanics parameters, the stress intensity factor, J integral, fracture toughness, and the failure assessment diagram required for structural integrity assessment will be introduced. A concept of structural integrity assurance of machine / structure in both the designing phase and the in-service phase are explained.
By the end of this course, students will be able to have the basic knowledge of fracture mechanics necessary for structural integrity assessment. Students also understand basic concept of structural integrity assurance of machine / structure in both the design phase and the in-service phase of them.
|✔ Applicable||How instructors' work experience benefits the course|
|In this lecture, the method of structural integrity evaluation for high-pressure vessels is introduced partially based on instructor's experience in the development of high pressure gas equipment for space use.|
Stress intensity factor, crack tip plastic zone, fracture toughness, fracture resistance, Dugdale model, J integral, failure assessment diagram, fatigue cracks, stress corrosion cracking, safe life design, fail-safe design, damage tolerant design
|✔ Specialist skills||Intercultural skills||Communication skills||Critical thinking skills||✔ Practical and/or problem-solving skills|
The class is designed to be taught in lecture style. Students are expected work on the homework related to the lecture after every class.
|Course schedule||Required learning|
|Class 1||The flow of the structural integrity assessment. Fracture assessment based on stress||The flow of the structural integrity evaluation assessment for the cracked-materials will be introduced.Fracture assessment based on stress is explained.|
|Class 2||Stress intensity factor and fracture assessment based on the factor||The concept of stress intensity factor (SIF) and the method of calculating the factor using SIF handbook will be introduced. Fracture assessment based on SIF and its applicable conditions are explained.|
|Class 3||Time dependent fracture||Crack growth evaluation for fatigue and stress corrosion cracking (SCC) based on stress intensity factor will be described.|
|Class 4||The design concept for the time-dependent fracture||Safe life design, fail-safe design and damage-tolerant design for time-dependent fracture will be introduced.|
|Class 5||J-integral||As stress intensity factor is invalid for non-linear fracture mechanics, fracture mechanics parameter, J-integral, used for non-linear fracture mechanics will be introduced.|
|Class 6||Fracture assessment based on J-integral and CTOD||Fracture assessment based on J-integral and its applicable conditions are explained. Concept of crack tip opening displacement (CTOD) and fracture assessment based on CTOD is also explained.|
|Class 7||Fracture assessment using failure assessment diagram (FAD), Examples of structural integrity evaluation||Fracture assessment using a failure assessment diagram (two-parameter method) will be explained. Structural integrity assessment results for piping with stress corrosion cracking will be introduced for an example.|
To enhance effective learning, students are encouraged to spend approximately 100 minutes preparing for class and another 100 minutes reviewing class content afterwards (including assignments) for each class.
They should do so by referring to textbooks and other course material.
No textbook is required.
Janssen, Michael et. al., Fracture Mechanics. London and New York: Spon Press; ISBN-13: 978-0415346221
Kobayashi, Hideo. Fracture Mechanics. Tokyo: Kyoritsu Shuppan; ISBN-13: 978-4320081000 (Japanese)
Kobayashi, Hideo. Structural integrity evaluation handbook. Tokyo: Kyoritsu Shuppan; ISBN-13: 978-4320081536 (Japanese)
Kobayashi, Hideo. Failure accident. Tokyo: Kyoritsu Shuppan; ISBN-13: 978-4320071650 (Japanese)
Level of understanding on the concept of structural integrity assessment and basis of fracture mechanics.
Final report 60%, exercise problems 40%.
Students must have knowledge of Fracture of Materials（MEC.C331.E）.