Issue 48

P. Dhaka et alii, Frattura ed Integrità Strutturale, 48 (2019) 630-638; DOI: 10.3221/IGF-ESIS.48.60 637 C ONCLUSIONS wo-dimensional finite element analysis was carried out for a flat-with-rounded-edge contact to study the influence of contact geometry on contact tractions. The finite element analysis results were compared with the analytical results and reasonable agreement was found between them. Further, the influence of geometric parameters viz. ‘a’ and ‘R’ was studied. A comparison was also made between finite element analyses carried out using elastic and elasto- plastic material behavior. Following conclusions can be drawn from the present study:  The finite element analysis results give better correlation with analytical results for lower value of a/R ratio.  The effect of ‘a’ is more prominent on contact pressure than varying ‘R’ because of the greater influence of ‘a’ on the contact zone size.  The effect of contact geometry on the contact stresses cannot be quantified using a unified parameter like a/R ratio or contact area under the present loading conditions.  Lesser filleting at the corners is found to be more beneficial as compared to generous fillets because it leads to a decrease in the peak tensile stresses. This is likely to delay the crack initiation and hence, longer fretting fatigue life. Further research is required to determine the extent of filleting which can be applied for a particular contact geometry.  Both elastic and elasto-plastic analysis give identical results and the deviation becomes significant only when the contact geometry starts approaching either non-conformal contact or flat punch with sharp corners.  The elastic analysis overpredicts the contact pressure and peak tensile stresses which is likely to result in a conservative estimate for fretting wear volume and fretting fatigue life. R EFERENCES [1] Papanikos, P., Meguid, S.A., Stjepanovic, Z. (1998). Three-dimensional nonlinear finite element analysis of dovetail joints in aero-engine discs, Finite Elem. Anal. Des., 29(3–4), pp. 173–186, DOI: 10.1016/S0168-874X(98)00008-0. [2] Söderberg, A., Andersson, S. (2009). Simulation of wear and contact pressure distribution at the pad-to-rotor interface in a disc brake using general purpose finite element analysis software, 267, pp. 2243–2251, DOI: 10.1016/j.wear.2009.09.004. [3] Bitter, T., Khan, I., Marriott, T., Lovelady, E., Verdonschot, N., Janssen, D. (2018). Finite element wear prediction using adaptive meshing at the modular taper interface of hip implants, J. Mech. Behav. Biomed. Mater., 77(May 2017), pp. 616–623, DOI: 10.1016/j.jmbbm.2017.10.032. [4] Cruzado, A., Urchegui, M.A., Gómez, X. (2012). Finite element modeling and experimental validation of fretting wear scars in thin steel wires, Wear, 289, pp. 26–38, DOI: 10.1016/j.wear.2012.04.018. [5] Kim, H.K., Lee, Y.H., Lee, K.H. (2008). On the geometry of the fuel rod supports concerning a fretting wear failure, Nucl. Eng. Des., 238(12), pp. 3321–3330, DOI: 10.1016/j.nucengdes.2008.08.010. [6] Shinde, D.U. (2008). Wear simulation of electric contacts subjected to vibrations, Auburn University. [7] Hills, D.A. (1994). Mechanics of fretting fatigue, 175, pp. 107–113. [8] Fouvry, S., Paulin, C., Deyber, S. (2009). Impact of contact size and complex gross-partial slip conditions on Ti-6Al- 4V/Ti-6Al-4V fretting wear, Tribol. Int., 42(3), pp. 461–474, DOI: 10.1016/j.triboint.2008.08.005. [9] Ciavarella, M., Hills, D.A., Monno, G. (1998). The influence of rounded edges on indentation by a flat punch, Inst. Mech. Engrs., 212, pp. 319-328. [10] Ciavarella, M., Demelio, G. (2001). A review of analytical aspects of fretting fatigue, with extension to damage parameters, and application to dovetail joints, Intnl. J. Solids and Structures, 38, pp. 1791-1811. [11] Ciavarella, M., Macina, G. (2003). New results for the fretting-induced stress concentration on Hertzian and at rounded contacts, 45, pp. 449–467, DOI: 10.1016/S0020-7403(03)00061-4. [12] Warmuth, A.R., Pearson, S.R., Shipway, P.H., Sun, W. (2013). The effect of contact geometry on fretting wear rates and mechanisms for a high strength steel, Wear, 301(1–2), pp. 491–500, DOI: 10.1016/j.wear.2013.01.018. [13] Juoksukangas, J., Lehtovaara, A., Mäntylä, A. (2013). The effect of contact edge geometry on fretting fatigue behavior in complete contacts, Wear, 308(1–2), pp. 206–212, DOI: 10.1016/j.wear.2013.06.013. [14] Mall, S., Naboulsi, S., Namjoshi, S.A. (2008). Contact geometry effects on fretting fatigue crack initiation behaviour of Ti–6Al–4V, Tribol. - Mater. Surfaces Interfaces, 2(1), pp. 25–32, DOI: 10.1179/175158308X320755. T