The Effect of Inclined U-Notch Geometry on Mode Ratio (KII/KI) under Mixed Mode (I + II) Loading

Document Type: Persian

Author

Abstract

In inclined U-notches, the mixed mode (I + II) loading occurs and the mode ratio can be increased by varying the notch angle. In this paper, the effect of the inclined U-notch geometry, i.e. the notch depth, the notch angle, the notch root radius, and the position of the notch with respect to supports, on the mode ratio (KII/KI) have been studied. Three-point bending and plane strain condition have been considered in this study. Finite element results using ANSYS have shown that the mode ratio increases by increasing the notch root radius. Also, it has been found that the mode ratio decreases by increasing the distance of the notch from the supports, and by increasing the notch angle. However, it is seen that the notch depth has complicated effect on the mode ratio. The variation of the mode ratio with respect to the notch depth has a relative maximum and a relative minimum.

Keywords


[1]     Gómez F.J., Elices M., Berto F., Lazzarin P., Local strain energy to assess the static failure of U-notches in plates under mixed mode loading, International Journal of Fracture, Vol. 145, 2007, pp. 29-45.

[2]     Gómez F.J., Elices M., Berto F., Lazzarin P., Fracture of V-notched specimens under mixed mode (I + II) loading in brittle materials, International Journal of Fracture, Vol. 159, 2009, pp. 121-135.

[3]     Ayatollahi M.R., Torabi A.R., A criterion for brittle fracture in U-notched components under mixed mode loading, Engineering Fracture Mechanics, Vol. 76, 2009, pp. 1883-1896.

[4]     Lazzarin P., Filippi S., A generalized stress intensity factor to be applied to rounded V-shaped notches, International Journal of Solids and Structues, Vol. 43, 2006, pp. 2461-2478.

[5]     Zappalorto M., Berto F., Lazzarin P., Practical expressions for the notch stress concentration factors of round bars under torsion, International Journal of Fatigue, Vol. 33, 2011, pp. 382-395.

[6]     Taghizadeh K., Berto F., Barati E., Local strain energy density applied to martensitic steel plates weakened by U-notches under mixed mode loading, Theoretical and Applied Fracture Mechanics, Vol. 59, 2012, pp. 21-28.

[7]     Torabi A.R., Fakoor M., Pirhadi E., Fracture analysis of U-notched disc-type graphite specimens under mixed mode loading, International Journal of Solids and Structures, Vol. 51, 2014, pp. 1287-1298.

[8]     Berto F., Lazzarin P., Gómez F.J., Elices M., Fracture assessment of U-notches under mixed mode loading: two procedures based on the 'equivalent local mode I' concept, International Journal of Fracture, Vol. 148, 2007, pp. 415-433.

[9]     Gomez F.J., Elices M., Berto F., Lazzarin P., Fracture of U-notched specimens under mixed mode: Experimental results and numerical predictions, Engineering Fracture Mechanics, Vol. 76, 2009, pp. 236-249.

[10] Berto F., Ayatollahi M.R., Fracture assessment of Brazilian disc specimens weakened by blunt V-notches under mixed mode loading by means of local energy, Materials and Design, Vol. 32, 2011, pp. 2858-2869.

[11]  Begini M., Benedetti M., Fontanari V., Monelli BD., Stress intensity factors of inclined kinked edge cracks: A simplified approach, Engineering Fracture Mechanics, Vol. 81, 2012, pp. 120-129.

[12] Niu L.S., Shi H.J., Robin C., Pluvinage G., Elastic and elastic-plastic fields on circular rings containing a V-notch under inclined loads, Engineering Fracture Mechanics, Vol. 68, 2001, pp. 949-962.