Extreme value analysis of ductile fracture surface by dimpled rupture associated with fracture behavior of tensile specimens

The extreme value analysis of the ductile fracture surface by dimpled rupture was performed associated with the fracture behavior of spheroidal graphite cast iron. A wide variation in the sizes of dimples is commonly observed on the ductile fracture surfaces of most materials. A statistical approach should be included to quantify the ductile fracture surfaces and relate them to the fracture behavior of the materials. The distributions of both the maximum dimple sizes in the unit area and the lateral growth factors of maximum dimples were well expressed as largest extreme value distributions for the tensile specimens with various plastic constraint factors. The location parameter, that is, the mode or highest point of the distribution, was directly related to the fracture strain and stress of the tensile specimen. Thus, the fracture behavior of the tensile specimens could be estimated approximately once the location parameter of the distribution is known by fractographic examination. Hence, extreme value analysis could be used as an attractive method for quantitative description of the ductile fracture surfaces correlated with the fracture behavior of spheroidal graphite cast iron.