Devising procedures for design and verification calculations of the beam-wall with edge breaks under static and cyclic loads

Abstract

This paper considers a thin-walled steel beam-wall with broken edges, which is part of many structures. The wall of this beam consists of two prismatic parts with a straight transition from a lower wall height to a higher one, forming a broken upper edge together with the edges of the prismatic parts. The bottom straight edge of the wall is attached to the cladding. The beam-wall is affected by static and cyclic nominal loads, which can cause the appearance of elastic-plastic deformations in the stress concentrator. This causes non-fulfillment of static strength and the appearance and growth of fatigue cracks. In the current work, procedures of design and verification calculation of a steel beam-wall with fractured edges at elastic static and cyclic elastic-plastic deformation in the stress concentrator are proposed. The material of the beam is ideal elastic-plastic. Features of the procedures are the possibility of optimal design under conditions of elastic and elastic-plastic deformation, using dependences only for optimal elastic design. A distinctive signature of the procedures is that, through Neiber's formula, elastic-plastic characteristics are not determined by known elastic ones, as usual, but vice versa. According to the established dependences for cyclic elastic-plastic deformations in the concentrator, the theoretical concentration coefficient is determined, which, in turn, is involved in determining the optimal geometric parameters. The procedures give reliable results with nominal symmetrical cyclic loads up to 0.6 of the yield strength. This is because Naber's formula always yields conservative results, causing excess strength. The procedures can be applied separately for stretching-compression and bending, and with their combined action