Simulation Studies of Nodular Iron’s Bull’s Eye Effect on Stress Concentration under Plane Stress Conditons

O.O. Oluwole, O.E. Olorunniwo

Materials Science and Engineering Department Obafemi Awolowo University, Ile-ife, Nigeria.

DOI: 10.4236/jmmce.2007.62007                

Abstract

A simulation study on the effect of the “bull’s eye” in ductile iron on stress concentrations was done in this work. Using the model of graphite nodules in a cavity, a two dimensional plate strip was subjected to plane stress conditions. The results were compared to the traditional theory of modeling the graphite as holes (cavity) in the iron matrix. In plane stress conditions, while the graphite in the hole model showed the hole as areas of stress concentration and therefore very critical as regards fracture, the hole model showed stress concentrated away from the holes making the holes not very critical factor as regards fracture. It was observed that areas of stress application were more critical than the voids when using the hole model. Also the graphite in the hole model was able to predict the good damping behaviour of ductile iron and the increasing elongation with decreasing nodule count.

Keywords

Simulation, Ductile iron, Bull’s eye, Stress concentration, Plane stress

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	Walton C.F and Opar T.J. (1981): “Iron casting handbook covering data on Grey, Malleable and ductile iron, Iron casting Society Inc. New York.
[2]	Smith W.F., (1993): “Structure and properties of Engineering alloys”, 2nd ed. McGraw- Hill, New York
[3]	Imasogie.B.I and Wendt.U. (2004) “Characterization of Graphite Particle Shape in Spheroidal Graphite Iron using a Computer-based Image Analyzer”, Journal of Minerals & Materials Characterization & Engineering, 3(1), 1-12,.
[4]	Ductile Iron Society (2006) “Ductile Iron Data for Design Engineers” http://www.ductile.org/didata/Section3/3part2.htm#Fracture%20Behaviour
[5]	Janowak.S.F,. Alagarsamy.A and Venugopalan.D (1990) “Fatigue strength of commercial ductile irons”, AFS Transactions, Vol.98, Pp.511-518.
[6]	Pundale. S.H., Rogers.R.J, Nadkarni.G.R (1998) ”Finite Element Modeling of Elastic Modulus in Ductile Irons: Effect of Graphite Morphology”, Journal of the American Foundrymen’s Society 98(102), 98-105
[7]	Bailey.E (1997) “Transgranular Fracture Surface in Ductile Iron” (sv.vt.edu/classes/.../97ClassProj/exper/bailey/www/bailey.html)