Experimental Study on Fatigue Performance of M60 High-Strength Bolts with a Huge Diameter under Constant Amplitude Applied in Bolt–Sphere Joints of Grid Structures

Abstract

The high-strength bolts’ fatigue is critical for the bolt–sphere joints of grid structures under the action of suspended cranes. High-strength bolts with a huge diameter are used more commonly when the span of grid structures and the burden of suspended cranes increase. However, few works have explored the fatigue performance of high-strength bolts with a huge diameter in bolt–sphere joints of grid structures. Thus, this paper examines M60 high-strength bolts with a huge diameter used in the bolt–sphere joints of grid structures. To this end, an AMSLER fatigue testing machine performed fatigue tests on 27 specimens under constant amplitude. The stress–fatigue life (S–N) curve was obtained by regression analysis and the corresponding constant-amplitude fatigue design method was established. The test results were compared with those of high-strength bolts in other specifications. The results showed that the M60 high-strength bolt has a higher fatigue strength. Furthermore, scanning electron microscopy (SEM) analyzed the macroscopic and microscopic fatigue fracture of the specimens, and the mechanism of the fatigue failure was examined. Our findings provide important experimental data for revising relevant Chinese and international codes and promote the application of high-strength bolts with a huge diameter used in the bolt–sphere joints of grid structures with suspended cranes. This study could fill the gap of fatigue performance data of high-strength bolts in different specifications for bolt–sphere joint grid structures, and provide a basis for further studies.

Axial Compression Bearing Capacity of Bolted Drum-Shaped Spherical Shell Joints: Experimental and Numerical Analysis

“…On the fatigue front, Tian et al [11] analyzed the rod element's ultra-low-cycle fatigue performance in a grid structure with BSJs, paving the way for understanding fatigue behavior under cyclic loading. Extending the fatigue analysis to high-cycle regimes, Xu et al [12], Qiu et al [13], and Zhou et al [14] each explored the high-cycle fatigue performance of M20, M30, and M60 high-strength BSJs, respectively, charting the corresponding S-N curves to illustrate the fatigue life of these joints. These assorted investigations not only broaden the understanding of BSJs' mechanical behavior under various conditions but also contribute to optimizing their design and application in engineering projects.…”

Comprehensive Fatigue Analysis and Practical Design Methodology for Weld Toes in the Sphere of Welded Hollow Spherical Joints in Grid Structures

“…For example, Qiu et al [8,9] conducted fatigue tests under constant and variable amplitude conditions on M30 high-strength bolts used in spatial grids, deriving the corresponding fatigue S-N curves. Moreover, to comprehensively investigate the fatigue performance of BSJs, fatigue tests were carried out on M20, M39, and M60 high-strength bolts [10][11][12].…”

Experimental Study on Variable-Amplitude Fatigue Performance of M60 High-Strength Bolts of Grid Structures with Bolted Spherical Joints

“…In addition, Yang [13], Qiu [14], and Zhou [15,16] conducted constant-amplitude fatigue tests on M20, M30, M39, and M60 high-strength bolts of grid structures with bolted spherical joints to study their fatigue performance. They obtained the corresponding stressfatigue life (S-N) curves.…”