Materials scienceLesson 2 of 2 in the course Composites and mechanical behaviour

Fracture Mechanics: Crack Growth, Toughness, and Engineering Assessment

5 flashcards · 5 quiz questions · 5 match pairs · 4 fill-in sentences · English

Save course
Lesson progress
0 / 5

Your progress is kept in this browser only.Sign up to save it

Summary

Fracture mechanics studies how cracks initiate and propagate in materials. It helps engineers decide whether flaws in a component are safe, how quickly they might grow, and when inspection or repair is needed.

Manufacturing, machining, forming, and service can leave small flaws inside or on the surface of a component. A flaw does not automatically cause failure: it becomes dangerous when the applied conditions cause it to grow into a crack or make the crack unstable.

All flashcards

What is fracture mechanics?
The field that analyzes crack loading and crack growth, and compares the driving force for propagation with the material's resistance.
Why can a flaw be present without causing immediate failure?
A flaw grows or becomes unstable only when its size, loading, material resistance, and environmental conditions combine to make crack extension possible.
What does the stress intensity factor describe?
It characterizes the crack-tip loading state in linear elastic fracture mechanics, particularly when the plastic zone is small.
What is fatigue crack growth?
Gradual crack extension caused by cyclic or repeated loading; for long cracks, growth is often related to the applied stress-intensity range, ΔKΔK.
Name two questions addressed by damage-tolerant design.
It estimates the maximum permissible crack size and the time needed for a crack to grow to that size, helping establish service life and inspection intervals.

Quiz questions

  1. What does fracture mechanics primarily study?Answer: Crack initiation and propagation in materials.
  2. In ideal linear elasticity, what stress is predicted at the tip of a perfectly sharp crack?Answer: Stress that increases without bound as the tip is approached.
  3. Which symbol commonly denotes the Mode I stress intensity factor in LEFM?Answer: KIK_I
  4. Which loading pattern commonly drives fatigue crack growth?Answer: Repeated or cyclic loading.
  5. How does damage-tolerant design manage flaws in a component?Answer: It assesses permissible flaw sizes and growth life to guide inspection and operation.

Based on the Wikipedia article Fracture mechanics, licensed CC BY-SA 4.0. Adapted into a summary, flashcards and quizzes.

More in Materials science

All Materials science lessons
Materials scienceCeramic Engineering: Processing, Microstructure, Composites, and Applications5 flashcards · 5 quiz questions · 4 gamesPlay free →Materials sciencePolymerization Mechanisms, Heat Control, and Photopolymerization5 flashcards · 5 quiz questions · 4 gamesPlay free →Materials scienceSteel: Composition, Processing, Microstructure, History, and Sustainability5 flashcards · 5 quiz questions · 4 gamesPlay free →Materials sciencePolymer Structure, Synthesis, Properties, and Applications5 flashcards · 5 quiz questions · 4 gamesPlay free →Materials scienceComposite Materials: Structure, Manufacturing, Properties, and Failure5 flashcards · 5 quiz questions · 4 gamesPlay free →