How to Plot a Stress-Strain Graph for Steel Sheet?

[ipocoyo]

Homework Statement

The maximum proposed stress of their new design is 670MPa. You have measured the tensile strength of pieces of their steel, using an appropriate "standard" to guide you. (What does this even mean?) The load vs displacement graph is given. The steel sheet is 3mm thick. The width of the sample is 12.5mm and the gauge length sample is 50mm. Plot the stress strain graph.

Homework Equations

mm load, N
7.52E-03 1.32E+03
1.69E-02 3.30E+03
2.61E-02 4.85E+03
3.68E-02 6.53E+03
5.02E-02 8.48E+03
6.34E-02 1.05E+04
7.74E-02 1.25E+04
9.42E-02 1.44E+04
1.04E-01 1.63E+04
1.13E-01 1.81E+04
1.27E-01 1.98E+04
1.44E-01 2.14E+04
1.80E-01 2.27E+04
4.48E-01 2.34E+04
8.10E-01 2.40E+04
1.13E+00 2.47E+04
1.47E+00 2.52E+04
1.80E+00 2.57E+04
2.16E+00 2.62E+04
2.50E+00 2.65E+04
2.81E+00 2.69E+04
3.09E+00 2.75E+04
3.42E+00 2.80E+04
3.76E+00 2.83E+04
4.18E+00 2.80E+04
4.63E+00 2.74E+04
5.12E+00 2.72E+04
5.47E+00 2.67E+04
5.71E+00 2.59E+04
5.71E+00 2.49E+04
5.71E+00 2.37E+04
5.70E+00 2.21E+04
5.30E+00 2.03E+04

The Attempt at a Solution

How do I find the stress for each load? I know that it is F/A, but I thought this only applied to rods and not a metal sheet? Or am i allowed to use 12.5x5 as the cross sectional area?

 

[Chestermiller]

Homework Statement

The maximum proposed stress of their new design is 670MPa. You have measured the tensile strength of pieces of their steel, using an appropriate "standard" to guide you. (What does this even mean?) The load vs displacement graph is given. The steel sheet is 3mm thick. The width of the sample is 12.5mm and the gauge length sample is 50mm. Plot the stress strain graph.

Homework Equations

mm load, N
7.52E-03 1.32E+03
1.69E-02 3.30E+03
2.61E-02 4.85E+03
3.68E-02 6.53E+03
5.02E-02 8.48E+03
6.34E-02 1.05E+04
7.74E-02 1.25E+04
9.42E-02 1.44E+04
1.04E-01 1.63E+04
1.13E-01 1.81E+04
1.27E-01 1.98E+04
1.44E-01 2.14E+04
1.80E-01 2.27E+04
4.48E-01 2.34E+04
8.10E-01 2.40E+04
1.13E+00 2.47E+04
1.47E+00 2.52E+04
1.80E+00 2.57E+04
2.16E+00 2.62E+04
2.50E+00 2.65E+04
2.81E+00 2.69E+04
3.09E+00 2.75E+04
3.42E+00 2.80E+04
3.76E+00 2.83E+04
4.18E+00 2.80E+04
4.63E+00 2.74E+04
5.12E+00 2.72E+04
5.47E+00 2.67E+04
5.71E+00 2.59E+04
5.71E+00 2.49E+04
5.71E+00 2.37E+04
5.70E+00 2.21E+04
5.30E+00 2.03E+04

The Attempt at a Solution

How do I find the stress for each load? I know that it is F/A, but I thought this only applied to rods and not a metal sheet? Or am i allowed to use 12.5x5 as the cross sectional area?

Yes, you are, although it should be 12.5x3. What made you think that it only applies to a rod?

It certainly applies to a sheet if the thickness and width are small compared to the gauge length.

Chet

 

[ipocoyo]

Yes, you are, although it should be 12.5x3. What made you think that it only applies to a rod?

It certainly applies to a sheet if the thickness and width are small compared to the gauge length.

Chet

Thank you for clearing up the confusion!