Test study and numerical simulation on shear performance of bolted connections of magnesium alloy plates

To promote the structural application of lightweight magnesium alloys, this study systematically investigates the room-temperature shear behavior of bolted magnesium alloy plate connections. Through the monotonic tensile testing of 13 double-shear specimens, the influences of plate thickness, bolt diameter, and pre-tightening torque were comprehensively evaluated. The experimental results reveal three primary failure modes: bolt shear failure, mixed failure, and net-section tensile failure of the core plate. Quantitative analysis indicated that increasing the bolt diameter and plate thickness from 6 mm to 12 mm improved the ultimate bearing capacity by up to 111.71% and 113.46%, respectively. Conversely, varying the pre-tightening torque significantly governed the initial stiffness but exhibited negligible effects on the ultimate capacity and failure mode. Furthermore, benchmarking against established international design codes revealed that the Chinese and American codes provide accurate capacity predictions, while the European standard remains overly conservative. Consequently, an empirical material modification factor is proposed, offering a refined theoretical framework for the practical design of magnesium alloy bolted joints.