PSI - Issue 13

Barış Tanrıkulu et al. / Procedia Structural Integrity 13 (2018) 1840 – 1844 Author name / Structural Integrity Procedia 00 (2018) 000–000

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As a result of the torque tension tests, all bolts were broken from the thread region and no fracture was observed in the head region. The thread region of the bolt still plays a critical role in fracture, although increasing the socket depth in the head region has reduced the strength of the head. The Torque-clamp loads obtained as a result of the tests are given in Figure 6 for each socket depth.

Figure 6. Torque-Clamp Load test results

4. Conclusion In this study, effect of socket depth at the head region of M8x1,25 10.9 DIN 912 fasteners was investigated for the sake of weight reduction. Finite element simulations as well as fatigue and torque-tension experiments were obtained. According to experimental tests, fasteners with socket depths determined according to simulations verified to meet the dimensional tolerances were failed from the thread region. Therefore, experimental results suggest that all the socket depths investigated in this study can be used in real applications for weight reduction. Further investigations will be carried out for different metric fasteners and qualities. References Grimsmo, E. L., Aalberg, A., Langseth, M., Clausen, A.H., 2016. Failure modes of bolt and nut assemblies under tensile loading. Journal of Constructional Steel Research, 126, 15-25. Griza, S., Silva, M.E.G.G., Santos, S.V.D., Pizzio, E., Strohaecker, T.R., 2013. The effect of bolt length in the fatigue strength of M24x3 bolt studs. Engineering Failure Analysis, 34, 397-406. Majzoobi, G.H., Farrahi, G.H., Habibi, N., 2005. Experimental evaluation of the effect of thread pitch on fatigue life of bolts. International Journal of Fatigue 27,189-196.