Volume 18, Issue 1 (January 1990)
Bending Strength of Gray Cast Iron
An experimental and theoretical study was made on the influence of the dimensions and geometry of cross sections on the bending strength of gray cast iron. The experiments revealed that the bending strength varies with specimen height, with higher bending strengths being recorded for smaller heights. This is explained by a region under the beam surface where the stress exceeds the tensile strength of the material. This overstressed depth is about 3 mm in 20 to 30 mm high beams and smaller in thinner beams.
The geometry dependence of bending strength is caused by non-linearity of the stress-strain curve. Numerical simulation by the fracture criterion with a constant overstressed depth showed that the bending strength of round bars is 10% higher than that of rectangular beams. In T cross sections, the influence of the section geometry is more marked. The experiments agreed well with the calculations.