applied fracture mechanics

Interacting Cracks Analysis Using Finite Element Method 369where Iand IIdenotes to elastic interaction factor for Mode I and II fracture,respectively.The SIF for Mode I and Mode II is determined using Displacement Extrapolation Method(DEM) by written APDL macro code in ANSYS (Madenci & Guven, 2006), and expressedasK IK IIE 2v v4v2 v43(1 )(1 ) L 23 5E 2u u4u2 u43(1 )(1 ) L 23 5where, E=Young Modulus, 3 4for plain stress, 34 /1for plain strain, L islength of element, v and u are displacements in a local Cartesian coordinate system and υ isPoisson’s ratio.(12)(13)Source: (Barsoum, 1974, 1976; Henshell & Shaw, 1975)Figure 2. (a) Eight nodes quadratic isoparametric elements (b) Parent element4. Findings and discussionTwo parallel edge cracks interaction will mainly referred to shielding effect rather thanamplification effect. The crack interaction is proportional to the magnitude of elasticinteraction factor I. The crack interaction will only exist at b/a < 3 (Z.D.Jiang, A.Zeghloul,G.Bezine, & J.Petit, 1990; Z.D.Jiang, J.Petit, & G.Bezine, 1990), the analytical formulation canbe expressed asin whichKI KFo n ( a / Wb , / a )(14)