Great explanation again, thank you :) Just one question, I guess you didn't mention but I was wondering about the effect of the Crack Closure Phenomenon on fatigue life, does it increase it or decrease it?
Why is largest tolerable surface flaw a0? Shouldn't the largest tolerable flaw be critical crack length since it is the point where failure occurs thus being the largest distance till failure?
You have a great point. The problem question should be, What is the acceptable initial crack size for the material to withstand the indicated load conditions for ten years? With this statement, the answer is logical.
If the largest intial flaw was the critical crack length, it would not survive the required number of cycles, instead experiencing brittle failure quite quickly. a0 is the surface flaw when N=0, so grows with every cycle, eventually reaching ac when the required number of cycles is reached.
Great work!
Great explanation again, thank you :) Just one question, I guess you didn't mention but I was wondering about the effect of the Crack Closure Phenomenon on fatigue life, does it increase it or decrease it?
I'm not an expert, I would assume it would increase fatigue life though. It's effectively reducing the stress by applying a closing stress.
@@TaylorSparks I was also thinking like that, but I wanted to confirm it with you, thank you a lot :)
Can you do a problem like this when the cycles aren't given but we still need to find the final crack length?
Good idea. I could probably prepare one of those
@@TaylorSparks that would be so helpful; thank you!
Sir can u tell me how y equals to 1.12 came
in the case of small surface crack Y is equal to 1.12
The stress intensity factor for the edge crack is: KI=1.12σ(aπ)^0.5
Thank you, Diego.
Why is largest tolerable surface flaw a0? Shouldn't the largest tolerable flaw be critical crack length since it is the point where failure occurs thus being the largest distance till failure?
You have a great point. The problem question should be, What is the acceptable initial crack size for the material to withstand the indicated load conditions for ten years? With this statement, the answer is logical.
If the largest intial flaw was the critical crack length, it would not survive the required number of cycles, instead experiencing brittle failure quite quickly. a0 is the surface flaw when N=0, so grows with every cycle, eventually reaching ac when the required number of cycles is reached.
where can i get values of fatigue crack growth properties of other materials ?
Literature. Articles on specific alloys or handbooks like CRC might have summaries if multiple materials