Don't understand what the problem wants.

[Physics_wiz]

Ok, this problem is from my Intermediate Mechanics of Materials class. Given are two tables for a specimen of medium-carbon steel with initial diameter 0.503 in and gauge length 2 in. The two tables are labeled "Elastic State" and "Plastic State".

The first table gives the Load vs. Elongation...Load ranging from 1,000 lbf to 9,200 lbf and Elongation ranging from 0.0004 into 0.0089 in.

The second table gives load vs. Area. Load ranging from 8,800 lbf to 14,800 lbf and Area ranging from 0.1984 in^2 to 0.1077 in^2.

The question is to plot the engineering stress-strain diagram using two scales for the unit strain (epsilon), one from zero to about 0.02 in/in and the other from zero to maximum strain.

I don't understand what it means by the bold part. Also, how can I plot stress vs strain for the plastic part if I only have the change in area...I don't have the elongation so I can't find strain.

Any help would be appreciated.

PS. Should I be posting this in the Engineering section instead?

 

[Gelsamel Epsilon]

I think it's asking you to plot a graph where the first part is in a separate scale to the 2nd, so that the graph is easier to look at. The first scale should be used from 0 to 0.02in and the next from there on.

It's so that a squiggly graph that goes all over the place is changed into a curve or a straight line with just multiple scales.

I've only done the first bit of Stress-strain so I don't have any idea how you would actually go about this question.

 

[quicknote]

As a scientist, my suggestion would be to first clarify any confusion with your instructor or classmates on the specific problem and what is expected of you. It is important to fully understand the problem before attempting to solve it.

In terms of plotting the engineering stress-strain diagram, you can use the information from both tables to create the plot. The first table gives you the load and elongation values, which can be used to calculate the strain using the formula strain = elongation/original length. The second table gives you the load and area values, which can be used to calculate the stress using the formula stress = load/area.

To plot the diagram, you can use two different scales for the strain, one from zero to about 0.02 in/in and the other from zero to the maximum strain. This will allow you to accurately represent the changes in strain over the range of values provided in the tables.

As for the plastic state, you can use the information from the second table to plot the stress-strain diagram for this phase. While you do not have the elongation values, you can still calculate the strain using the change in area and the original length. This will give you an idea of the behavior of the material in the plastic state.

In conclusion, it is important to have a clear understanding of the problem and to use all the information provided to accurately plot the engineering stress-strain diagram. If you are still unsure, it may be helpful to seek assistance from your instructor or classmates. And yes, posting this question in the Engineering section may also provide helpful insights and perspectives.