FROM ONE NOTCH TO A BRANCHING CRACK
Fracture mechanics from Griffith’s energy balance to branching cracks
A fine scratch can make a glass rod break far below the stress its atomic bonds could hold, because a crack grows whenever the energy it releases pays for the new surfaces. Start with that balance, then follow the crack as it grows stably, runs away, chooses a path and, at high speed, splits.
Sharp cracks · Chapters 1–4
When a crack can grow
Balance released elastic energy against the cost of new surface, measure it from a compliance curve, decide whether growth stays under control, then read the same criterion from the stress near the tip.
Start with the energy balance →Cracks as fields · Chapters 5–8
How a crack chooses its path
Replace the sharp crack by a damage band, predict when a notch starts to crack and test the prediction, then follow fast cracks into branching and disorder.
Start with the damage band →Eight chapters, with examples and experiments
01 L1
Why a crack needs energy to grow
Why does a scratched glass rod break at a stress far below what its atomic bonds could hold?
Read and try →02 L2
Find the energy release rate from a compliance curve
How can a record of load and displacement tell you how much energy a crack releases as it grows?
Read and try →03 L2
When a growing crack stays under control
Why does the same crack creep forward in one test and run through the specimen in another?
Read and try →04 L2
Stress near a crack tip and the stress intensity factor
If the stress at a sharp tip is infinite, what number tells you how close the crack is to growing?
Read and try →05 L3
Model a crack as a narrow band of damage
How can a computer let a crack choose its own path, without a rule for where the tip should go?
Read and try →06 L3
Predict when a notch starts to crack, then test the prediction
Can a sharp-crack energy release rate, computed separately, predict when a phase-field notch begins to crack?
Read and try →07 L4
Fast cracks and branching in a dynamic phase-field model
Why does a crack that runs fast enough stop travelling as a single straight line?
Read and try →08 L4
How frozen disorder roughens a fast crack path
If every piece of a material is a little different, how much does that move a fast crack off its straight line?
Read and try →