Fatigue life assessment using Miner's Rule - YouTube Engineering Academy
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- เผยแพร่เมื่อ 1 ต.ค. 2024
- In this video you learn everything you need to know about fatigue life assessment! You learn how fatigue failures look like, what influences the service life time of loaded parts and bearings and how the service life curve of those elements can be characterized.
Afterwards is shown how operation with a single load or with a load spectrum results to fatigue damage accumulation and how the occurring damage and the remaining service life can be calculated using Miner’s Rule. At the end, a special consideration of how damage with a tress amplitude below the fatigue endurable stress can be considered by using the Miner modified and Miner elementary hypothesis.
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This methodology of fatigue analysis is a history and useless for real material and for practical applications. S-N curve is a key source of wrong results of analysis.
I can understand, that S-N curves can be challenging to apply due to their statistical dispersion, as they don't provide precise results but probabilities. However, claiming that they are outdated and a source of wrong results is not accurate. They are still state-of-the-art!
@fdta2536 In your opinion, which calculation method is currently considered to provide "correct" results?
Your videos are very good. Can you make a video on how to get to the simplified load cycles (N1, N2, N3, etc. and Sigma1, Sigma2, Sigma3, etc.) from the stresses measured in real life?
Your Videos are easy to understand , but many are on german , along with german language , translate your videos to english also
Excellent!!
Amazing !!
But, i don't know which of bearing you are talking about ? And also, the force F on the bearing is horizontal vertical or total ?
Please if you could clarify those points
Thank you for your question, I try to clarify it. The video talks about roller bearing fatigue in general. No matter if you have a ball bearing, a cylindrical roller bearing or a tapered roller bearing, the fatigue can be calculated according to this method. The force F is the dynamic equivalent bearing load P_eq, that is calculated in general from the radial load F_r and the axial load F_a according to: P_eq = X * F_r + Y * F_a. Depending from the load an inner stress level occurs that I called sigma. Every load level sigma_x has a corresponding lifetime L_x
The criterion of correctness of fatigue analysis results is only: the results of virtual analysis directly correlate with physical test results without statistic optimization. Most correct calculation method is based on the Kinetic Theory Strength of Materials.We can prove by demo test.
The disclosing of nature of the real materials and its behavior under loading made possible to conduct any strength analysis without simulations (Miner’s Rule, S-N curve, RainFlow) and traditional software development. It is possible by unique method of KTSM testing instead ASTM durability test. It is a tool for numerous engineering tasks solution, related with strength and reliability assessment of the real materials without any results’ dispersion. “Ask material” method.
Thank you for understanding.
sehr schön! gibt es das gleiche Video auf deutsch? es wär sehr hilfreich!
Es gibt ein Video zur Schadensakkumulation bei Wälzlagern, das die gezeigten Prinzipien auf Deutsch darstellt: th-cam.com/video/SRrjnsYlW7g/w-d-xo.html
@@abraxas596 vielen Dank für die Antwort! Das Video habe ich mir entdeckt.
Unglaublich gut erläutert! Mach weiter.
can we use it for hydrodynamic bearring too?
No, hydrodynamic journal bearings are calculated totally different. There should be no finite lifetime of a correctly designed journal bearing!
Is Li same as Ni on the miner equation
Li is not the same as Ni: Li is the lifetime on stress level i, Ni is the number of stressing load cycles on that level.