Like I said, it is the work done by the sample. The force exerted by the sample on its surroundings is directed toward the sample, and the displacement at the boundary where the work is being done is directed toward the sample. So the work done by the sample is positive. The work done on the sample is negative.KevMilan said:What about the area under the loading curve? Is it the workdone on the sample or by the sample?
Yes. The force we apply and the displacement are in the same direction.KevMilan said:For the area under the loading curve, shouldn't it be the workdone ON the sample?
Because we are the one putting force/stress on it? Could you clarify? Thankyou.
Work done ON the sample, but that area is the sum of the shaded area and the "white" sliver.KevMilan said:What about the area under the loading curve? Is it the workdone on the sample or by the sample?
KevMilan said:One more thing, why is it the workdone BY the sample (not ON)? (Is it because we're not putting any force/tension on the sample when unloading?) Any simple explanation would be very helpful!
We are applying a force on the sample during unloading. But that force is opposite to the displacement so we are doing negative work. If you interpret the dark area as negative, then it represents the work done ON the sample during unloading.KevMilan said:One more thing, why is it the workdone BY the sample (not ON)? (Is it because we're not putting any force/tension on the sample when unloading?)
'On' or 'By' is not necessarily obvious and it's actually a bit anthropomorphic, imo.KevMilan said:One more thing, why is it the workdone BY the sample (not ON)?