Version 1.0, August 31, 2001, Copyright, Hugh Jack 1993-2001
· While necking, the cross section at one point decreases, thus increasing the stress. In turn this continues rapidly until fracture.
· The strain hardening of some materials occurs as they are stretched, the Ultimate Tensile Strength increases, but Young's modulus remains the same.
· Each material will have it's own stress-strain curve and these are determined experimentally, and found in abundance in handbooks.
· If a material is brittle, it does not deform much and simply breaks. Or simply the ultimate and rupture strengths are the same.
· Ductile materials deform quite a bit before the ultimate stress, necking typically occurs before rupture.
· The area under the stress strain curve indicates toughness. A larger area under a stress strain curve will make a material that must be extensively deformed before it will fail.
· Creep is an effect that can lead to permanently elongated specimens,
