In this lecture, damage mechanics and fracture mechanics (fatigue life estimation, creep life estimation) for structural design
will be learned along case studies.
- Understand fracture mechanics and its necessity, and perform strength calculations using them.
- Understand the high-temperature deformation of a material from the viewpoint of material science and calculate the strength (lifetime calculation) of the material using constitutive equations.
- Understand the fatigue of materials and calculate the life of structures from crack propagation characteristics and fatigue life constitutive equation
| Class schedule | HW assignments (Including preparation and review of the class.) | Amount of Time Required | |
|---|---|---|---|
| 1. | Explanation of deformation and fracture phenomena of materials and class schedule ・ Liberty ship brittle fracture accident |
See syllabus | 190minutes |
| 2. | Ideal strength of material and strength of material including defect ・ Ideal strength of material ・ Energy conditions for rapid failure ・ Stress intensity factor, critical stress intensity factor ・ Demonstration on index of adhesive strength using fracture toughness |
Preparation p1 of textbook and handouts | 100minutes |
| Review the energy conditions of rapid failure. | 90minutes | ||
| 3. | Failure mechanism ・ Microscopic mechanism of rapid fracture (cleavage fracture) ・ Example of cleavage fracture (fracture of steel at low temperature, polymer) ・ Microscopic mechanism of rapid fracture (ductile tearing) ・ Example of ductile tearing (metal fracture at room temperature) |
Preparation p64-72 of textbook and handouts | 100minutes |
| Review on microscopic mechanism of destruction. | 90minutes | ||
| 4. | Fracture mechanics parameters and their measurements ・ Small-scale Yielding ・ Fracture toughness test (standard compact tension test, etc.) |
Preparation p85-100 of textbook and handouts | 100minutes |
| Review to better understand small-scale yielding | 90minutes | ||
| 5. | Accident due to rapid failure and case studies ・ Rapid failure of pressure tank ・ Safety design method for pressure equipment using the leak before break |
Preparation p102-113 of textbook and handouts | 190minutes |
| 6. | Fatigue fracture ・ Classification of fatigue fracture ・ Fatigue behavior of crack-free members ・ High cycle fatigue ・ Low cycle fatigue ・ Life calculation using high cycle fatigue life law |
Preparation p195-203 of textbook and handouts | 100minutes |
| Review on life calculation using high cycle fatigue life law | 90minutes | ||
| 7. | Fatigue behavior of cracked members ・ Crack growth and Paris law ・ Crack growth test method ・ Prediction of fatigue life using fracture behavior and crack growth law of pre-cracked material ・ Examples of accidents on aircraft |
Preparation p185-194 of textbook and handouts | 100minutes |
| Review on fatigue life calculation using Paris law | 90minutes | ||
| 8. | Creep and creep rupture ・ Definition of high and low temperature ・ Creep test and creep curve ・ Stress dependence of creep strength |
Preparation p185-194 of textbook and handouts | 100minutes |
| Review on stress dependence of creep strength | 90minutes | ||
| 9. | Temperature dependence of high temperature strength and stress relaxation ・ Temperature dependence of strain rate ・ Arrhenius law ・ Stress relaxation and creep ・ Example of tightening bolts for turbine generator casing |
Preparation p114-121 of textbook and handouts | 100minutes |
| Review on examples of tightening bolts for turbine generator casing | 90minutes | ||
| 10. | Kinetics of diffusion ・ Fick's law ・ Diffusion in solids (atomic energy and diffusion, frequency) ・ Diffusion mechanism (lattice diffusion, grain boundary diffusion, dislocation core diffusion) |
Preparation p143-150 of textbook and handouts | 100minutes |
| Review on diffusion in solids | 90minutes | ||
| 11. | Creep mechanism ・ Creep mechanism and constitutive equation ・ Dislocation creep ・ Diffusion creep (viscous creep) ・ Deformation mechanism diagram |
Preparation p160-162 of textbook and handouts | 100minutes |
| Review on creep constitutive equation | 90minutes | ||
| 12. | Creep damage and creep rupture ・ Constitutive equation of rupture life ・ Prediction of creep life by parameter method (Larson-Miller parameter, Orr-Sherby-Dorn parameter, Manson-Harferd parameter, Manson-Brown parameter) |
Preparation p162-164 of textbook and handouts | 100minutes |
| Review on prediction of creep life by parameter method | 90minutes | ||
| 13. | Creep (viscoelasticity) of resin material ・ Stress-strain curve of polymer ・ Relationship between polymer Young's modulus and temperature ・ Mechanical model of viscoelastic material (Kelvin-Voigt model, generalized Maxwell model) ・ Time-temperature conversion rule |
Preparation p165-169 of textbook and handouts | 100minutes |
| Review on generalized Maxwell model | 90minutes | ||
| 14. | Final exam and its commentary | Review all handouts | 180minutes |
| Total. | - | - | 2650minutes |
| Practice Problem | Final exam | Total. | |
|---|---|---|---|
| 1. | 10% | 20% | 30% |
| 2. | 10% | 25% | 35% |
| 3. | 10% | 25% | 35% |
| Total. | 30% | 70% | - |
Exercises 30 points, final exam 70 points. More than 60 points to pass.
- Course that cultivates a basic self-management skills
| Work experience | Work experience and relevance to the course content if applicatable |
|---|---|
| Applicatable | Lecture of fracture of mechanics is given Based on the practical experience of reliability calculation for design and manufacture of ships and bridges. |
Last modified : Tue Mar 24 04:10:51 JST 2020