The effect of electron beam incidence angle on the dynamic fracture of metal rings and cylinders

This work investigated how the incidence angle of the electron beam affects the dynamic fracture of metallic cylinder shell. Cylinder shell made of steel was blazed with electron beam and cut into ring and cylinder specimens. Flash X-ray radiography was used to register the fracture of the ring specimen. Fragments from the cylinder specimens under internal explosive loading were recovered and analyzed by SEM, and the fragment mass distribution was derived by statistical analysis. When the incident angle alpha of the electron beam was 0 degrees, the fracture of the metal ring was along the normal direction of the outer surface. When alpha was 30 degrees and 45 degrees, the fracture of the metal ring was oblique. The distributions of recovered fragments were similar regardless of alpha. The fracture of the metallic cylinder shell under explosive loading was well controlled at all alpha. The recovered fragments from the cylinder specimen with alpha = 30 degrees or 45 degrees had an oblique quadrangular prism shape, whose the length was 30% larger than the fragments from the cylinder specimen with alpha = 0 degrees. The fracture near the outer side of the cylinder specimen was along the melting region of the electron beam. The fracture mode of the cylinder specimen was tension-shear mixed fracture when alpha = 0 degrees but shear fracture when alpha = 30 degrees or 45 degrees.