i have initial and final gauge length and diameter and also have max load. Now i have to draw stress strain diagram. I know how to draw that graph but i a not provided with failure load or yield load so i am not sure how to graph. We had performed experiment and data was given by lecturer which had only one load data that is max load, no other points. Appreciate any help. Thanx in advance

Stress equals load divided by cross sectional area of test sample.

Strain equals [(Final length)-(Initial Lelngth)]/(Initial Length)

Since you have only one data point, all you can plot is the stress (y axis) and strain (x axis) corresponding to breakage or yielding.

At loads less than the failure load, there should have been a linear relationship between stress and strain, with a slope equal to Young's modulus for the material. However, you say that you have no data points in this regime.

Reading this article may help you:
http://en.wikipedia.org/wiki/Stress%E2%80%93strain_curve

Thnx drwl but i knw the fomulas but i dnt knw hw to plot a graph wen juz max load is given.

You can plot one point. That is all. If you were not told how much the sample stretched, you cannot even plot that.

To draw a stress-strain diagram without the yield load or failure load, you can use the given maximum load and the initial dimensions of the specimen.

Here's how you can proceed:

1. Calculate the cross-sectional area: Use the initial diameter to calculate the cross-sectional area of the specimen using the formula A = (π/4) * d^2, where A is the area and d is the diameter.

2. Calculate the engineering stress: Divide the maximum load by the cross-sectional area calculated in step 1. The formula for engineering stress is σ = Fmax / A, where σ is the stress and Fmax is the maximum load.

3. Calculate the engineering strain: Use the initial and final gauge lengths to calculate the change in length (ΔL). The engineering strain is then calculated as ε = ΔL / L0, where ε is the strain, ΔL is the change in length, and L0 is the initial gauge length.

4. Plot the data points: Plot the engineering stress on the vertical axis and the engineering strain on the horizontal axis. Use the calculated values from steps 2 and 3 to plot a single data point on the graph.

Keep in mind that without additional data points, the resulting stress-strain diagram will only show a single point, representing the material's behavior at the maximum load. It will not provide information about yield, failure, or any other characteristic points on the graph.

Note: This procedure assumes that the material behaves in a linear-elastic manner. If the material exhibits plastic deformation or shows other non-linear behavior, additional data points and information would be required to accurately construct the stress-strain diagram.