Finite Element Analysis of the Stiffness of a Plug-in Device Connection with a Modified Stiffener

Abstract

Modular steel construction offers significant advantages in fabrication efficiency, installation speed, and structural adaptability; however, the performance of inter-module connections remains a critical concern, particularly under lateral loading conditions. This study aimed to evaluate the mechanical behavior and stiffness characteristics of a modified plug-in device connection incorporating a U-shaped stiffener with bolted stiffener-to-column connections. The research employed finite element analysis using ANSYS Mechanical. Numerical models were first validated against previous experimental studies using two reference connections, SC1 and SC2, before analyzing the modified model, SC_Mod. The validation results showed differences of 7% and 9% between the numerical and experimental results, confirming the acceptable accuracy of the developed models. The SC_Mod connection achieved an initial translational stiffness of 21,500.46 kN/m and rotational stiffness of 26,739.38 kNm/rad. Compared with SC1, the translational and rotational stiffness increased by 243% and 163%, respectively, while increases of 127% and 82% were observed relative to SC2. The modified connection reached a maximum load of 633.5 kN, with yielding occurring at approximately 22.6 mm deformation and failure occurring at 120.39 mm. These findings demonstrated that the bolted U-shaped stiffener configuration substantially improved connection stiffness, load transfer capacity, ductility, and constructability, making it a promising alternative for steel modular building connections while preserving the practical advantages of modular construction systems.