# Calculating 0.2% proof stress of aluminium

by cmgames
Tags: aluminium, proof, stress
 P: 12 i see your point however i am basing my calculations on what one of my lecturers emailed me~:~ "If, for example, your horizontal axis shows 5.0mm of extension, and you measure this as being say 220mm, it follows that 1mm in reality is represented by 44mm on your axis (220 divided by 5) Now multiply 0.2% of gauge length by 44 to obtain the amount of offset "
P: 2,284
 Quote by cmgames i see your point however i am basing my calculations on what one of my lecturers emailed me~:~ "If, for example, your horizontal axis shows 5.0mm of extension, and you measure this as being say 220mm, it follows that 1mm in reality is represented by 44mm on your axis (220 divided by 5) Now multiply 0.2% of gauge length by 44 to obtain the amount of offset "
I don't see the point in scaling the graph down to a smaller scale. I must be missing something. Sorry I couldn't help more.

CS
 P: 1 i thought the graph should be stress-strain graph? why is it force-elongation graph? is it the same/?
P: 1
 Quote by dewking i thought the graph should be stress-strain graph? why is it force-elongation graph? is it the same/?
Stress is Force/Original Area
Strain is Elongation/Original test piece Length

The two graphs are not the same, but the shapes are identical, as the original area and original length are constant.

But that is a good point, why isn't your graph a Stress-Strain one?

 Related Discussions Mechanical Engineering 6 Special & General Relativity 178 Engineering, Comp Sci, & Technology Homework 3 General Math 31 General Physics 0