What's the difference between inelastic and plastic? 1

[Alaazaki]

Hello,

Is there a difference between inelastic and plastic, I know that they are the same literally but i ask if they have a different definition in structural analysis.

 

[rn14]

btrueblood, it just depends on how pedantic you would like to be. At what point would you say a beam is "truly" inelastic? For that matter when would you deem it "truly" elastic? I don't believe any materials with which contemporary structural engineers work with can be said to have no residual (permanent) deformation after a load has been removed but it is reasonable to say it is elastic because those deformations are essentially zero where a structural engineer is concerned. Conversely, I believe it is reasonable to say inelastic when a beam has exceeded first yield and begins to take on permanent deformations which are large enough to concern a structural engineer. My point is that plastic hinging in the extent to which I mentioned it (context) is not a complex issue and doesn't need to be further convoluted with unnecessarily complex language.
Going back to my initial point of context... These details typically are of no consequence to a structural engineer but if you are a material scientist they probably are. It does not mean one is all of a sudden wrong. Its a matter of scale really.