Distribution of shear fragments classified by morphology

Abstract

In studies on metal shell under internal explosive loading, unlike brittle metals, ductile metals usually exhibit shear fracture. Existing literature mostly focuses on slip fracture caused by unidirectional shear fracture, in fact, the shell fractures in the two directions of maximum shear stress, making morphology of the fragments diversified, considering fragment morphology in the distribution may achieve a better description. In previous studies, Poisson mixtures and Weibull mixtures model are only used for fragment distribution statistics as a functional form, and parameters (weight coefficient and distribution modulus) in the function lack physical process description. In this paper, an experimental study on the fragmentation of 50SiMnVB steel shell under TNT internal explosive loading was carried out. Through the observation and analysis of recovered fragments, the shear fragments with cross-sections of parallelogram, right-angled trapezoid, and isosceles right-angled triangle are divided into three types: A, B, and C. According to “A-type fragments created by the parallel through-the-thickness fractures, B-type and C-type fragments created by interaction of intersecting fractures,” the morphological parameters of fragments in the distribution model were derived, including fragment size (width, length, thickness, mass, etc.), shape parameters, and weight coefficient. Weibull mixture distribution model is used to describe the distribution of the total fragments, whereas Weibull distribution is used to describe the distribution of each type of fragment. Through the comparison of theoretical calculations and experimental data, the applicability of the theoretical model in the field of “shear fracture of ductile steel shell under internal explosive loading” is verified.