- #1
joe465
- 94
- 0
Homework Statement
For each material calculate the cross sectional area in m². Each sample is of rectangular cross section 20mm by 1mm.
Produce Stress and Strain tables for the data.
TEST DATA FOR X
(N) EXTENSION (mm)
1000 0.48
2000 0.60
3000 0.70
4000 0.80
Homework Equations
CSA = Length * Width
mm to m = divide by 1000
Stress = Force / Area
Strain = Extension / original length
The Attempt at a Solution
First convert mm to m by dividing by 1000.
20mm * 1mm = 0.020m * 0.001m = 0.00002m^2
Area = 0.00002m^2
Now i presume because it states all 3 materials have the same cross section they have the same Cross sectional area?
Now for the stress and strain data.
There are more numbers but i have only provided a few for an example.
Stress = Load (N) / Area (m^2)
(N) (mm ext) Stress(N/m^2) Strain (m/m)
1000 0.48 50000000 0.024
2000 0.60 100000000 0.03
3000 0.70 150000000 0.035
4000 0.80 200000000 0.04
The values for stress seems strangely high when compared to another materials values where stress is 70, 100, 150, 200 and 220. (these are pre-given values). When calculating strain i used the length given by the first question 20mm as the original sample length, however underneath the tables for the test data giving the Load and extension data it gives an additional value ''original length of sample X: 375mm''. Which figure should i use, the original sample length as given in question 1 or the additional information?
This baffles me and without knowing which figure to use will affect the rest of the results and observations?
Thanks for any help given in advance,
Joe