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Computation of Mixed-Mode Stress Intensity Factors for Cracks in Three-Dimensional Functionally Graded Solids |
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| Authors: | Matthew C Walters Glaucio H Paulino Robert H Dodds Jr |
| Affiliation: | 1Dept. of Civil and Environmental Engineering, Univ. of Illinois at Urbana-Champaign, Newmark Civil Engineering Laboratory, 205 N. Mathews Ave., Urbana, IL 61801. 2Dept. of Civil and Environmental Engineering, Univ. of Illinois at Urbana-Champaign, Newmark Civil Engineering Laboratory, 205 N. Mathews Ave., Urbana, IL 61801 (corresponding author). E-mail: paulino@uiuc.edu 3Dept. of Civil and Environmental Engineering, Univ. of Illinoisat Urbana-Champaign, Newmark Civil Engineering Laboratory, 205 N. Mathews Ave., Urbana, IL 61801. |
| Abstract: | This work applies a two-state interaction integral to obtain stress intensity factors along cracks in three-dimensional functionally graded materials. The procedures are applicable to planar cracks with curved fronts under mechanical loading, including crack-face tractions. Interaction-integral terms necessary to capture the effects of material nonhomogeneity are identical in form to terms that arise due to crack-front curvature. A discussion reviews the origin and effects of these terms, and an approximate interaction-integral expression that omits terms arising due to curvature is used in this work to compute stress intensity factors. The selection of terms is driven by requirements imposed by material nonhomogeneity in conjunction with appropriate mesh discretization along the crack front. Aspects of the numerical implementation with (isoparametric) graded finite elements are addressed, and examples demonstrate the accuracy of the proposed method. |
| Keywords: | Cracking Three-dimensional analysis Computation Stress intensity factor |