Interfacial micromechanics study on contact modeling for bolted joints

Abstract

Bolted joints represent the discontinuity of the assembled structures, so their contact characteristics contribute significantly to the overall static and dynamic performances of the mechanical system. For the multi-scale geometrical properties of contacting surfaces, an interfacial micromechanics modeling method is proposed to predict contact characteristics using the fractal theory. Meanwhile, the interaction effect caused by the successive tightening of multiple bolts is incorporated into the contact analysis, which characterizes the residual preload of bolts to improve the contact load model. Three contact models for the bolted joint are examined by combining the interfacial micromechanics model with the transfer matrix method for multi-body systems, the finite element method, and the virtual material method. A comparison with the experimental data of a dumbbell-shaped bolted structure is conducted to validate the contact models and estimate their practicality and accuracy. The models show their advantages and drawbacks, which depend on the complexity of the bolted structure, the requirements of computational efficiency, and the research focus.