Outer Fiber Stress Factor
For rectangular specimens in a 4-point bend test:
Outer fiber stress factor = (width * thickness2)/(1.5 *(1 - load span/ support span) * (support span))
For rectangular specimens in a 3-point bend test:
Outer fiber stress factor = (width * thickness2)/(1.5 *(support span))
For cylindrical specimens in a 4-point bend test:
Outer fiber stress factor = (ð * diameter3)/(8 *(1 - load span/support span) * (support span))
For cylindrical specimens in a 3-point bend test:
Outer fiber stress factor = (ð * diameter3)/(8 *(support span))
