True stress, true strain and work hardening

In this video I introduce true stress and true strain which we can then use in the strain hardening equation to quantify the relationship between the load and the resulting elongation in a sample loaded beyond the yield strength, but prior to necking.

[@Laserman232]

But why is it called the strain hardening equation? It was not explained in this video, however I will try my best to explain for others watching and wondering... In the region of plastic deformation, dislocations move around at the atomic level by slip. Common dislocations occur has edge dislocations, screw dislocations, mixed dislocations. The dislocations that a metal for example is able to experience effects how much it can deform plastically. There are many contributing factors to this, such as grain size, temperature, %cold work and others. However one thing that should be said is as the metal plastically deforms, grains begin to disalign. This creates diffuculty for dislocations to move through the metal. These difficulties in dislocations moving is what makes a metal deform less which therefore makes it stronger. By doing this, you're decreasing the ductility, however you're increasing tensile strength, yield strength and hardness. Many times this is done purposely in processes like cold working or precipitation hardening. So getting back to the original question, in this plastic region, the metal is being hardened because of the increase is dislocations in the crystal. Further ways of hardening to decrease dislocation movement is by introducing interstitial atoms (for example: alloying), these atoms create stress in the crystal such as tension and compression which prevent dislocations from moving through. The same can be said for substitutional atoms.

[@劉育豪-f8q]

He is error Strain hardening eq is about dislocation density. This is called Hollwon’s eq

Typing error in 5:37. Integration gives \varepsion_T=\ln (l_i) - \ln (l_0) which can be simplified in to the final formula which is in red box in 6:01.

[@nurathamer9265]

I need problem and solution about true and engineering stress strain

[@abduld1937]

Thanks for these online videos! I was just going through these, and I noticed that at 5:40 I think you made an integration mistake. It should be ln(l_i) - ln(l_0) because the antiderivative of 1/x is ln(x) + C. After FTC part 2, it simplifies to ln(l_i/l_0) by logarithm properties.

[@selfmotivationselection9877]

+Scott Ramsay hello nicely explained but at uts is that true strain which is equal to exp. coefficient or engg. straim???

[@SharinganUser4tw]

hi, i come converting from engineering to true strain stress but my curve has still a negative slope is this possible or am i doing anythign wrong? (my curve is a concrete stress strain tention curve )

[@ozencanmoglu8668]

why we dont use F/Ɛ diagram.Is it not usefull ?

[@Raju-we6ow]

Sir, what is the relation between true strain and engineering strain for compression? I used the same expression i.e. True strain = ln(1+Ec), but the value is coming negative. So is there any other formula or we should just write the negative value of strain.

[@aman2426]

Always the Indian Guy starting his comment with "Sir". Come out of the 1850's please.

[@vishank7]

@@aman2426 This is called manners btw. Come out of your egoistic self will ya?

[@AhmadHalawan]

who is scott Ramsay?

[@ShazNoman]

kzbin.info/www/bejne/pou3iICYi6iSjrM

[@connorfitzgerald640]

I like Scott Ramsay

[@AnmolSharma-jk1pg]

laugh less and teach more

[@sharshabillian]

Shut up shoarma

[@alxsotoa]

Or maybe go read a book

[@vishank7]

@Anmol Sharma Get a life dude.