Have a licensed Airframe and Powerplant mechanic inspect it! Or, better yet, have an Authorized Inspector determine if the part needs repair or replacement! Don't fly it until it's been inspected by a licenced, experienced, professional aircraft maintenance person! ===
Crack Propagation === I assume this means you have a crack in the skin of your aircraft. The rate that cracks may grow, wether slow or fast, depends on the hardness of the material and the stress at the leading edge of the crack. Heat-treated and hardened aluminum or steel will be more brittle and therefore the crack will grow faster. High-strength steel, such as on landing gears, may crack but the crack will only grow a few thousandths of an inch before it fails completely.
stress
Lift, Weight, Thrust, Drag, Pressure
Normal stress on parts that occurs over time.
Roberto Ballarini has written: 'The effects of crack surface friction and roughness on crack tip stress fields' -- subject(s): Crack surfaces
yes especially if you are under stress
This depends on the type of window/glass as some glass is thermally treated. However, stress in the glass from contraction/expansion can make a noticeable crack. Heat alone will not crack glass but it will, over time, melt it.
know it's when a crack collides
A crack is caused by tension not compression because tension pulls matter apart while compression pushes matter together
A fatigue crack typically appears as a small, hairline fracture on the surface of the material. It can be perpendicular to the direction of the applied stress and may have a characteristic beach-mark pattern that indicates the progressive growth of the crack over time.
Faulting is caused by stress in the rock layers, the stress can break and crack the rock causing a fault. There are two types of faults a normal fault and a reverse fault.
That depends entirely on the individual airframe and the stress it has absorbed. All military aircraft have stress meters.
Yes but concrete is going to crack if it has too much stress. If it's a decorative column then use a 4000 mix. If it has a load on it you will have to figure how much weight is going to be on it.