Experimental study on the effect of shape of bolt and nut on fatigue strength for bolted joint

2018 International Conference on Material Strength and Applied Mechanics

材料科学;力学

Matsunari, T.^1 ; Oda, K.^2 ; Tsutsumi, N.^2 ; Yakushiji, T.^3 ; Noda, N.A.^4 ; Sano, Y.^4

Graduate School of Engineering, Oita University, 700 Dannoharu, Oita

870-1192, Japan^1

Division of Mechanical Engineering, Oita University, 700 Dannoharu, Oita

870-1192, Japan^2

National Institute of Technology, Oita College, 1666 Maki, Oita

870-0152, Japan^3

Mechanical Engineering Department, Kyushu Institute of Technology, 1-1 Sensui-cho, Tobata-ku, Kitakyushu-shi

804-8550, Japan^4

关键词: Curvature radii;    Effect of curvature;    Fatigue experiments;    Fatigue strength;    Initiation and propagation;    Pitch differences;    Stress amplitudes;    Stress-controlled fatigue;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/372/1/012016/pdf
DOI  :  10.1088/1757-899X/372/1/012016

来源: IOP

【 摘 要 】

In this study, the effect of curvature radius of the thread bottom and the pitch difference between of M16 bolt and nut on fatigue strength for bolted joint is considered experimentally. The M16 bolt-nut specimens having the two kinds of thread bottom radii and the pitch differences are prepared. The S-N curves for bolted specimens with different thread shapes are obtained by the stress-controlled fatigue test (stress ratio R>0). The experimental results are compared and discussed in terms of stress analysis. The finite element method is used to make a simulation of the fatigue experiment and the mean stress and stress amplitude at each thread bottom of bolt are analysed. It is found that the initiation and propagation of crack are changed by introducing the pitch difference of α=15 μm from the crack observation in cross section of the bolt specimens after the experiment. Furthermore, the fatigue life can be extended by increasing curvature radius of thread bottom and introducing the pitch difference.