Oops.
I think I found a mistake in Harry’s paper.
From Wickapedia "Toughness can be determined by measuring the area (i.e., by taking the integral) underneath the stress-strain curve and its energy of mechanical deformation per unit volume prior to fracture. The explicit mathematical description is:
Energy/volume= the integral from 0 to failure of σ dε
Where ε is strain a σ is stress
Another definition is the ability to absorb mechanical (or kinetic) energy up to failure. The area covered under stress strain curve is called toughness.
If the upper limit of integration up to the yield point is restricted, then the energy absorbed per unit volume is known as the modulus of resilience. Mathematically, the modulus of resilience can be expressed by the product of the square of the yield strain times the Young's modulus divided by two."
The curves shown by Harry are wrong because he assumed the failure stress is equal between the different modulus’s. It is not.
E.G. Do the math and the IM6 the Modulus of resiliance is essentially equal to the S glass. So the lower modulus does not have a theoretical advantage as stated.
Reply With Quote