ANALYSIS OF APPROXIMATED CURVED CRACKS IN HOMOGENEOUS AND GRADED MATERIALS
Main Article Content
Abstract
In this paper two stages of analysis are studied. In stage I, the influence of crack shape on the
crack-tip stresses, critical loads and subsequent propagation direction is investigated via a simple
analytical model for cracks in homogeneous materials. This model is verified through finite element
simulations using ANSYS. It is demonstrated that accurate predictions of mechanical energy release
rate and crack deflection angle may be obtained from a smaller number of crack shape parameters.
In stage II, this concept is extended to curved cracks in functionally graded materials (FGMs).It is
common that analytical and computational models of fracture in FGMs have focused almost
extensively on straight cracks. If it can be demonstrated that straight cracks give an adequate
approximation of curved cracks in graded materials, then the existing solutions for straight cracks
provide a sufficient foundation for fracture analysis of FGMs. On the other hand, if straight cracks
do not adequately approximate curved cracks in FGMs, then the development of solutions for non
straight cracks in graded materials is priority. Three cracks shapes approximations are performed to
compare with the actual crack in isotropic and graded materials. The crack propagation and the SIFs
were simulated using finite element method. It was concluded that piecewise linear crack shapes
provide a significantly better approximation than straight crack shapes. Accordingly, analytical
solutions for piecewise linear cracks in graded materials would be very useful, and should be a
focus of future work in this area.
Article Details
Section
How to Cite
References
ANSYS (2007) Version 11 Documentation, ANSYS Inc. Canonsburg,PA.
Ashby MF, Jones DRH (1996), Enginering Materials 1: An introduction to their properties and applications, 2nd edition, Butterworth Heinemann.
Broek (1991), Elementry Engineering Fructure Mechanics, 4th ed., Kluwer, Dordrecht.
Chetterjee (2006), On The Elasic Moduli Of Some Heterogeneous, J Mech Phys Vol 13:223-227.
Dag_, S., Kadio_lu, S. and Yahgi, O.S., 2004, “Circumferential Crack Problem for an FGM Cylinder Under Thermal Stresses”, Journal of Thermal Stresses, Vol. 22, pp. 659-687.
Erdogan (2006), Fracture Mechanics of FGM, Vol. 12, pp. 112-122.
Jin, Z.-H. and Paulino, G.H., 2001, “Transient Thermal Stress Analysis of an Edge Crack in a Functionally Graded Material”, International Journal of Fracture, Vol. 107, pp. 73-98.
Jin & Batra(2007), Some Basic Fracture Mechanics Concepts On FGM, J Mech Phys Vol 45:20-27.
Kitagawa H, Yurk R and Ohira T (1975) , Crack Morphological Aspects In Fracture Mechanics, Engineering Fract Mech : 515-29.
Leevers Ps, Radon JC and Cuvler LE (1980), Fracture Trajectories In A Biaxially Stressed Plate, J Mech Phys Vol. 24: 381-390.
Mattew T. Tllboork (2005), Thermal Fatigue Of Heterogeneous Materials, Thesis.
Noda N, Oda K and Ishi K(1994), Analysis Of Stress Intensity Factor For Curved Cracks, JSME Int vol.6: 360-365.
Taya , Kfouri & Khan (2005), Functionally Graded Thermal Barrier Coating, Material Science Vol. 10: 102-114.