TITLE:
Effect of Tightening Torque on a Hybrid Stainless-Steel/Glass-Epoxy Composite Bolted Joint under Tension at Room and Cryogenic Temperature
AUTHORS:
Christian Schmitt, Pawel Lipinski, Arnaud Kremeur, Julien Capelle
KEYWORDS:
Bolted Joint, Glass-Epoxy Composite, Hybrid Steel-Composite, Tightening Torque, Insert, Cryogenic Temperature
JOURNAL NAME:
Engineering,
Vol.17 No.12,
December
31,
2025
ABSTRACT: The aim of this work is to study the behavior of a double-lap hybrid metallic/composite bolted joint under quasi-static tension loading at room temperature (RT) and cryogenic temperature (CT). The bolted joint is composed of two metallic stainless-steel plates and a woven glass-epoxy composite material plate. The area around the fastened hole is reinforced with a hybridization constituted by a succession of metallic stainless-steel foils and composite plies. Three-dimensional finite element analyses have been performed to evaluate the stress state in the bolted joint, especially in the vicinity of the bolt hole and in the hybridization area. The finite element model has taken into consideration the mechanical properties of the involved materials, the effects of contact between the different sheets of the assembly and the pre-stress in the bolt. The influence of the inserts (sleeves) in use around the bolt is studied to define the best geometry of the bolted joint. Three configurations were studied, namely, without a sleeve and with one or two sleeves. Finite element results have shown that the most appropriate design is a bolted joint with one sleeve. For the latter configuration, quasi-static tensile tests have been performed for several clamping force levels. Experimental results showed a moderate influence of the tightening torque on the behavior of the bolted joint, while temperature has a strong effect on the tensile strength, which increases with decreasing temperature. The fracture images showed that, in most cases, the hybrid metal/composite bolted joint failure mode corresponded to the shear-out failure.