Effect of the cutout in the flange ring on mechanical behaviors of bolted joints

Bolted flanged joints designed based on present available engineering design rules can't be effective lightweight structures. There is non-uniform stress distribution in the flange ring under the operation load. Cutouts in the ring may improve structural efficiency. Three dimensional nonlinear finite element analyses were used as tools to ensure the effect of cutout on mechanical behaviors of flanged joints. Totally four flanged joints, three with cutouts and one without, were analyzed to get detailed stress and displacement. The results show that the cutout has obvious effect on joints. The stiffness of the flange ring decreases with cutouts and the bending and rotation displacement of the flange increase. Contact opening displacement at the joint interface and bending stress in the flange fillet also increase. The cutoff volume is the major reason for those variations. Contact stress variation between flange faces is also changed with cutouts.