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There are two components given with each stress-strain curve. Determine the component that maximise the load carrying capacity and that maximise the elastic deformation per unit applied load.

Is it right for the maximum load carrying capacity to look for the highest yield stress and for the maximum elastic deformation per unit applied load to look for the highest strain at failure?

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  • $\begingroup$ Short answer ... yes and no. Longer answer .. Draw a free-body diagram for the system and relate what is being asked to what is measured in the test. Making this modification to the question will help you appreciate how a complete answer can then be obtained. $\endgroup$ Oct 18 '18 at 16:04
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    $\begingroup$ Is there an image of the strain-stress curves? $\endgroup$
    – user190081
    Oct 18 '18 at 16:32
  • $\begingroup$ It is measured the load and the extension. I don't know what load carrying capacity and elastic deformation per unit applied load mean. What are the relationships between them and load and extension? $\endgroup$
    – SeLa
    Oct 18 '18 at 18:02
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Do you know how a typical stress-strain curve looks like? Take a look at this image: enter image description here

The load carrying capacity is the maximum load an item can carry before a failure occurs. Please note that these curves deal with stresses and not with forces. However, assuming the two components you are examining share the same geometry and are subjected to the same load pattern - you can compare their ultimate strength values. The larger the ultimate strength in this case - the larger the load carrying capacity.

The elastic deformation begins at the origin of graph and ends at the Yield Strength point (as long as the curve is linear). The larger the strain at this point the larger the elastic deformation is.

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  • $\begingroup$ I dont think that we should intermediately assume that that is the shape of the stress-strain curve that OP is talking about, what if OP is talking about the curve for concrete or rubber or cast iron or glass? $\endgroup$
    – user190081
    Oct 18 '18 at 20:14
  • $\begingroup$ Would it actually matter? His question is so basic that the answer is valid for a lot of cases. $\endgroup$ Oct 18 '18 at 20:26
  • $\begingroup$ Of course it matters, first of all this is the engineering stress-strain curve for the specific material, what if we test a brittle material? or viscoelastic ? this curve is not a general curve, young modulus of rubber has a different definition, yielding doesn't occur for all materials. I give you an out, use resiliency. $\endgroup$ Oct 19 '18 at 6:49
  • $\begingroup$ As far as I remember, this site deals with ENGINEERING, not philosophy. Maybe the guy asked about the stress-strain curve of an hydrogen atom during quantum tunnelling process? Most chances are I gave him exactly what he needs in order the understand the simple question he got. Sometimes it seems the guys here pay more attention into grammar mistakes or philosophic/mathematical nuances instead of looking at the full picture. $\endgroup$ Oct 19 '18 at 7:04
  • $\begingroup$ Every engineer who at least attended in material 101, knows the difference between TRUE and ENGINEERING strain-stress curve, your diagram is called ENGINEERING stress-stress curve. This is not about language or grammar, and of course users should emphasise on technicality. I didn't downvote the question just a comment to remind you the diagram is about the specific material as the OP has a general concern. $\endgroup$ Oct 19 '18 at 14:41

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