Influence of Strain‐hardening on the Load‐carrying Behaviour of Bearing Type Bolted Connections

Abstract

yield strength ratios fu/fy (e.g. fu/fy > 1.50), which are significantly above common values for conventional structural steels, while at the same time maintaining high ductility.This results in a pronounced hardening behaviour, which can have positive effects in various applications. One such application is in bolted connections, where either the net cross-section weakened by the presence of the bolt hole or the hole bearing resistance becomes decisive in design. In non-prestressed bolted connections, which are very common in building construction and other structures that are primarily loaded by static loads, the majority of the load is transferred through bearing action between the bolt shank and the hole wall. The build-up of the hole bearing resistance is associated with increasing deformations (elongations) of the bolt hole. With the applied load approaching the ultimate bearing resistance, the elongation of the bolt hole becomes considerably large, which can affect the overall performance of the structure.

Process Simulation of Hole Mandrelling in Steel Aircraft Parts

“…During hole mandrelling, the tool, that is, a mandrel, is pushed through the hole with a slightly smaller diameter compared to the tool itself. As a result of plastic deformation, the diameter of the hole increases, the processed metal layer in the hole is hardened and any uneven areas of the surface are levelled so the surface of the hole becomes very smooth [13]. The stress the surface of the hole is subjected to during mandrelling is, in most cases, compressive, which has a favourable effect on the structure of the layer of metal on the surface and the operational properties of that surface.…”