You can transfer the Load Displacement Curve to Stresss - Strain Curve and then draw tangent to the stress - strain curve from the original and take the slop of this tangent in order to calculate the E (i.e. Stress/Strain).

Convert load vs displacement data to stress vs strain. The slope of the stress-strain curve will give the Young's Modulus (E). For Poisson's Ratio, you have to collect strain data in other direction also. Alternatively you can find out Modulus of Rigidity (G) and calculate Poisson's Ratio (nu) from the relation between E, G and nu.

As you performed the tensile test by yourself so load cell has given you load and extensometer displacement data....

Measure the diameter and gauge length of specimen.....from dia you can have original area....divide load by this area and you will get engineering stress......displacement is actually change in length so divide it with original length and you will get engineering strain.......plot these and slope of curve is young's modulus.....

for poisson's ratio divide transverse strain to above engineering strain....

Thank You sir for your kind help. 

It depends on your tested materail.

1.secant slope through the initial zero point

2.tangent slope throught some point

3.some methods for special material

Dear Cameron Sir,

This is indeed a good way of calculating the young's modulus of a material. In fact I need a very accurate value. Thank You for your kind help.

Dear Yingying Sir,

I had used Aluminium Alloy (AA 413.0 heat treated samples). I am calculating it by the second method. Basically I am differentiating the stress-strain curve and trying to calculate the value of slope at yield point. 

Dear Cameron Sir,

I can use the publicly listed properties of E and Poisson's ratio from Matweb.com specifically for As-Received Specimen (Non-Heat Treated). But for heat treated sample, the value of Young's Modulus changes (as far as I know). I am using tangent slope method since I am doing non-linear analysis (Bi-linear), for which I need Tangent Modulus and strain hardening exponent (n). Can you please specify me the variation of strain hardening exponent with temperature. I am confused with strain rate dependent constitutive equation which expressed strain hardening exponent (n) as a function of strain rate. The constant used in the equation are found to be strongly dependent on temperature. But it is used for Hadfield Steel. I am not sure whether I can use the same for Aluminium AA 413.0 alloy. Thank You.

Dear Cameron Sir,

I totally agree with you regarding the complication of problem but I think that I got the solution. For calculating strain hardening exponent (n) from the stress strain curve of heat treated samples, I used non-linear curve fitting in inelastic region of the curve and used the equation stress=K*Strain^(n) (Hollomon's equation). It gives the approximate values of strain hardening exponent (n) and strength index (K). 

You can transfer the Load Displacement Curve to Stresss - Strain Curve and then draw tangent to the stress - strain curve from the original and take the slop of this tangent in order to calculate the E (i.e. Stress/Strain).

you can not get the E and Nu from the simple tens'on test data accurately because most of the times these data are not that accurate especially in the elastic region. to get those data, you need to do the test with a tensile machine equipped with extensiometers. it the data obtained with extensiometers can be zoomed enough to read the exact slope of the elastic region. to get hardening index, the plastic region up to 20 % (not more) of the elongation should be implemented. ASTM standard has the full method.

E=(Lo(F2-F1))/(Ao(d2-d1))

Where: Lo = original length (gauge length)

Ao = original cross sectional area

F1 = Force at level 1

F2 = Force at level 2

d1 = displacement or extension at 1

d2 = extension at 2

For definition of the koffitsiyent of Poisson you haven't enough data. Special sensors for measurement of cross deformations of a sample are necessary