Effective Width of the Free Flange of the Ship’s Wide Beam with an Axis Bend

The strain-stress state (SSS) of a free flange of a constant width of the typical ship thin-walled beam with a break of an axis of I-section at elastic deformation is analyzed. The beam consists of a tapered part and prismatic parts of different heights, adjoining it. In the result of handling of data of SSS there was the methodology created for definition of an effective width and appropriate reduction factor for the dangerous cross section and along tapered part in the wide range of change of geometrical parameters. As investigations showed the behavior of a flange of an inclined/tapered part and in places of its break is complex for the reason of complex warping/deplanation and presence of stress concentrators, with the result that in a flange there is no plane stress state completely realized, necessary for calculation of an effective width after classic method. That’s why for the determination of an effective width of a flange of an inclined part there was used projection of components of SSS into its plane, so that a (quasi-) plane stress state was achieved, suitable for the application of the classic methodology of calculation of an effective width. As a result, the effective width depends on five independent parameters: width and thickness of a flange; angle of inclination of a tapered part; fillet radius in the place of transition from little height of a web to a tapered part; relation of heights of little and larger webs. Determination of an effective width took place considering only shear lag, without taking into account of buckling of a flange and web; there is excluded the influence of flexure component caused by local bending of flange platting by the way of definition of components of SSS at its middle surface. Also there is presented the verification of the Suslov formula assigned for the dangerous cross section of the investigated beam in the narrow range of changeable geometric parameters.