1. Mechanics of Materials Lab
Lecture 13
Fracture Mechanics
Mechanical Behavior of Materials Section
Jiangyu Li
University of Washington
Jiangyu Li, University of Washington

2. Jiangyu Li, University of Washington
Displacement Mode
Sliding mode
Opening mode
Tearing mode
Jiangyu Li, University of Washington

3. Jiangyu Li, University of Washington
Stress Distribution
Jiangyu Li, University of Washington

4. Jiangyu Li, University of Washington
Plane Stress/Strain
Plane Stress:
Thin
Poisson Contraction
Plane Strain:
Thick
Constrained in z direction:
Jiangyu Li, University of Washington

5. Stress Intensity Factor: Tension
Jiangyu Li, University of Washington

6. Jiangyu Li, University of Washington
Example
Edge crack
b=120mm
t=12mm
If a=18mm,
Maximum P with safety factor 3?
If P=100 kN and safety factor is 3,
What is the maximum allowable a?
Jiangyu Li, University of Washington

7. Stress Intensity Factor: Bending
Jiangyu Li, University of Washington

8. Stress Intensity Factor: Circumferential Crack-
Jiangyu Li, University of Washington

9. Stress Intensity Factor
Jiangyu Li, University of Washington

10. Jiangyu Li, University of Washington
Energy Release Rate
Jiangyu Li, University of Washington

11. Jiangyu Li, University of Washington
Superposition
Jiangyu Li, University of Washington

12. Jiangyu Li, University of Washington
Superposition
Jiangyu Li, University of Washington

13. Jiangyu Li, University of Washington
Assignment
Mechanical Behavior of Materials
8.6, 8.11
Jiangyu Li, University of Washington