You're right, there could be something happening in microscale that will cause such behaviour.
Of course in composites the story can be completely different than in other materials
For now, I'll stick to use the reversed loading curve, with "Goodman like" mean stress correction suggested by...
Hi rb1957
maybe the data is saying that plastics are susceptible to fatigue in compression ?
According to curve from my initial post, material is suspectible to fatigue in compression, for higher stresses than for tensile or alternating load
or that alternating stress sign is more critical...
I agree that plastics will behave differently, however I would not expect totally inverse relation - where tensile mean stress is going to improve the lifetime
To support my feeling I'm attaching an article where several polymers (PC, PP, ABS) have been tested at different R ratios and each of...
Hello
I've recently started to deal with fatigue analysis of plastic components.
I found some strange relationship innthe fatigue curves - where the S-N curve coming from the 0-max (pulsating tensile) cycle is higher than the curve from the alternating one (compression-tension). Looking to the...
