Material, relationship between "E" and yield strength
Material, relationship between "E" and yield strength
(OP)
I am working on a plastics problem where there are a variety of formulations with a varitety of strength properties. I can see that when the material Modulus of Elasticity, E increases the yield strength does as well, and vice versa. Is there a real realationship here? If I get a range of E values and a range of yield values is it correct to assume that there is a linear relationship between the max and min values of each.
Thanks
EngForm78
Thanks
EngForm78





RE: Material, relationship between "E" and yield strength
do you mean the yield stress?
If yes, as far as I know, there is no such relationship.
Alex
RE: Material, relationship between "E" and yield strength
good57morning@netzero.com
RE: Material, relationship between "E" and yield strength
i think engform78 was asking is the a relationship between yield stress and E; rather than stress = E*strain.
as mihaiupb notes, there isn't. different "flavours" of Al (2024, 7075) have the same E, but different yields.
RE: Material, relationship between "E" and yield strength
It is just a coincidence and there is no linear relationship. For a lot of metals, the stronger they are, the stiffer they are.
A simple exception is Titanium which is not very stiff compared to steel but is stronger than many steels. Titanium is not, however stronger than the strongest steels.
RE: Material, relationship between "E" and yield strength
I'm sure if you narrow the material down sufficiently, you can get some sort of relationship. For example, I think ACI has a formula for E vs. fc' for concrete. If you were just varying one component of the plastic, you could probably do something similar.
I seem to recall from long ago that E with plastics was also time dependent, which would further complicate matters.