A modified stiffness method considering effects of hole tensile deformation on bolt load distribution in multi-bolt composite joints

Published on Aug 15, 2019in Composites Part B-engineering7.635
· DOI :10.1016/J.COMPOSITESB.2019.05.010
Libin Zhao21
Estimated H-index: 21
(Beihang University),
Ziang Fang3
Estimated H-index: 3
(Beihang University)
+ 2 AuthorsJianyu Zhang25
Estimated H-index: 25
(Chongqing University)
Sources
Abstract
Abstract The bolt holes of multi-bolt composite joints have bearing deformation caused by bolt loads and hole tensile deformation resulted from bypass loads. However, the hole tensile deformation was neglected in the existing stiffness method, because the stiffness formula of laminates without hole was applied for the joined hole laminates, which leads to a relatively rough prediction of the bolt load distribution, especially for the multi-bolt joints with larger numbers of bolts, in which the bypass loads are much bigger than the bearing loads. To improve the accuracy of the existing stiffness method, a modified stiffness method was proposed. In this method, based on the effect mechanism of the hole tensile deformation on the deformation compatibility condition, a concept of an additional stiffness corresponding to the hole tensile deformation and its calculation method were presented to modify the deformation compatibility equation. The bolt-load ratios predicted by the modified method and the existing method were compared with those obtained from FE models. It follows that the modified method possesses higher precision, and the improvement of the prediction accuracy is more conspicuous as the number of the bolts increases. The presented method shows overwhelming advantages over the existing method.
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