The modulus of toughness it the area under the stress-strain curve. A high modulus of toughness represents a material that can absorb a large amount of energy before failing. For example you would want material for a bumper to have a large modulus of toughness so it can absorb large impacts rather than transfering the energy to the passengers. Thanks for trying to help anyways,
What's up Dylan-
4 more days until I am a professional bum.
if you are looking for modulus of elasticity data, listen to dylan. If you are interested in toughness which basicly is the materials ability to deform instead of shatter, you should probably look at impact strength. There are a bunch of different test methods so make sure you compare apples to apples. If you are interested in how the metal responds when there is a crack, then you can look at fracture toughness. All these properties are on matweb.
In metalurgy there are a lot of people that are not metalurgists that are experts in a certain field. Most of the time these people have bastardised the terms to the point it is difficult for someone outside that field to understand what they mean. Modulus of toughness is something like that. To a metalurgist modulus means the slope of a line on a graph. Toughness would be represented on a stress strain curve as an area, so I don't see how there could be a modulus of toughness with "correct" terminology. That does not mean the term isn't used somewhere in a specific industry. If it is, I would like to learn.
In my consulting buisness I make a lot of money translating what the weldors say into what the metalurgists can understand.
Oops You were too fast for me.
That is sometimes refered to as energy absorbtion. I just checked and it is not on Matweb. The only time I have had to use energy absorbtion was in positioning the equivalency of a composite safety device to a steel device for a race car. I don't think it is a good number to look at from a design perspective and it is not easy to find in tables. You might look at some of the other toughness numbers I mentioned in the other post. The reason is the stress strain curve is generated by loading the specimen slowly in a tensile test machine. In the Charpy test, a machine swings a big hammer down through a part breaking it in half. They measure how far the hammer swings back up. This loads the part fast. Some materials act significantly differently at high strain rates, and instead of elongating like they do in the tensile test they just snap like a brittle material. I hope that helps some.
Basically I need the data for a paper I'm writing in my materials class and I spoke with my professor and he recommended that I include Modulus of Toughness data. Since he's the one that's going to be giving me a grade I guess I better listen. I realize that the Modulus of Toughness is more of a theoretical value since it can change drastically depending on loading conditions but at the same time if he tells me to include something I should probably do it.
Thanks for your help Gordon,
They had my picture on the dart board in the aculty office when I was in college, so I wont give you any advice on how to deal with your professor. I have never heard that phrase before and I am surprised it came from someone in academia. Who's your prof and out of what school?
"Modulus of Toughness
The work done on a unit volume of material as a simple tensile force is gradually increased from zero to the value causing rupture is de fined as the Modulus of Toughness. This may be calculated as the entire area under the stress-strain curve from the origin to rupture. Toughness of a material is its ability to absorb energy in the plastic range of the material."
I’ve often looked at things from an energy per unit volume perspective before also, but not usually to the point of rupture, although like you said for things like bumpers that would be cool. We often look at the area under the curve to an endurance limit stress value especially in spring design.
I’m sure you could come up with an equation for “energy per unit volume to rupture” as a function of “modulus, yield strength, ultimate strength and elongation” that would be pretty close. And these values are all really easy to find.
A real rough approximation without taking in to account 2% offset or the specific shape of the curve in the plastic range would be
½(Sy^2/E) + ((Sy+Su)/2)*elongation
I just scratched that out in a couple of minutes so let me know if it’s close to the values you find or just totally wrong?<br +>
Gordon was on the faculty dart board because he proved a lot of professors wrong when we were in school.
It’s good to see you on this board Gordon!