PSI - Issue 37

Jesús Toribio et al. / Procedia Structural Integrity 37 (2022) 1037–1042 Jesús Toribio / Procedia Structural Integrity 00 (2021) 000 – 000

1042

6

SC ( a / b =0.2)

s / s 0 = 0) s / s 0 = 1/2) s / s 0 = 1) s / s 0 = 0) s / s 0 = 1/2) s / s 0 =1)

Y = 0.968 – 0.581 ( a / d ) + 5.786 ( a / d ) 2 Y = 0.838 + 0.027 ( a / d ) + 0.071 ( a / d ) 2 Y = 0.634 + 0.082 ( a / d ) + 0.429 ( a / d ) 2 Y = 0.778 – 0.569 ( a / d ) + 3.107 ( a / d ) 2 Y = 1.056 – 0.349 ( a / d ) + 0.714 ( a / d ) 2 Y = 1.292 – 1.101 ( a / d ) + 2.786 ( a / d ) 2

C ( a / b =1)

where Y is the dimensionless SIF defined in eq. (2). 5. Conclusions 1. The stress intensity factor solution for a cracked bolt subjected to remote tension loading was obtained for various crack shapes and crack depths, at different crack points. 2. Two improvements were introduced into the computation in order to increase the accuracy of the results: the displacement of the quarter -point nodes (normal plane) and the shifting of the adjacent nodes (crack line). 3. A polynomial second order interpolation was carried out with the numerical results, to provide analytical expressions to be used in fatigue life prediction. 4. The K -values for tension loading are higher at the crack center of shallow cracks and the crack surface of circular cracks. 6. In Memoriam: A Tribute to Juan de la Cierva The paper is a heartfelt tribute to the memory of the prominent Spanish engineer Juan de la Cierva, inventor of “autogiro”, the predecessor of modern helicopter. References Astiz, M.A., Elices, M.., 1980. On the application of the stiffness derivative method to two and three-dimensional fracture problems. Proceedings 2nd International Conference Numerical Methods on Fracture Mechanics, pp. 93-106. James, L.A., Mills, W.J., 1988. Review and synthesis of stress intensity factor solutions applicable to cracks in bolts. Engineering Fracture Mechanics 30, 641. Mackay, T.L, Alperin, B.J., 1985. Stress intensity factors for fatigue cracking in high-strength bolts. Engineering Fracture Mechanics 21, 391. Nord, K.J., Chung, T.J., 1986. Fracture and surface flaws in smooth and threaded round bars. International Journal of Fracture 30, 47. Reibaldi, G.G., 1984. Stress intensity factor solutions for a cracked bolt. Advances in Fracture Research (Fracture 84), Vol. 2, pp. 1177-1183. Springfield; C.W., Jung, H.Y., 1988. Investigation of stress concentration factor-stress intensity factor interaction for flaws in filleted rods. Engineering Fracture Mechanics 31, 135-144.