Numerical analysis of 2-D crack propagation problems using the numerical manifold method

• Published in: Engineering analysis with boundary elements Vol. 34; no. 1; pp. 41 - 50
• Main Authors: Zhang, H.H., Li, L.X., An, X.M., Ma, G.W.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 2010; Elsevier
• Subjects: Boundary-integral methods; Complex crack problems; Computational techniques; Crack propagation; Exact sciences and technology; Fracture mechanics (crack, fatigue, damage...); Fundamental areas of phenomenology (including applications); Mathematical methods in physics; Numerical manifold method; Physics; Solid mechanics; Static elasticity (thermoelasticity...); Stress intensity factor; Structural and continuum mechanics; Stress intensity factor; Numerical manifold method; Complex crack problems; Crack propagation; Near field; Branching; Crack array; Stress concentration; Discontinuity; Singularity; Stress analysis; Surface crack; Rupture; Gauss formula; Modeling; Stationary crack; Crack tip; Asymptotic approximation
• ISSN: 0955-7997; 1873-197X
• DOI: 10.1016/j.enganabound.2009.07.006

The numerical manifold method is a cover-based method using mathematical covers that are independent of the physical domain. As the unknowns are defined on individual physical covers, the numerical manifold method is very suitable for modeling discontinuities. This paper focuses on modeling complex crack propagation problems containing multiple or branched cracks. The displacement discontinuity across crack surface is modeled by independent cover functions over different physical covers, while additional functions, extracted from the asymptotic near tip field, are incorporated into cover functions of singular physical covers to reflect the stress singularity around the crack tips. In evaluating the element matrices, Gaussian quadrature is used over the sub-triangles of the element, replacing the simplex integration over the whole element. First, the method is validated by evaluating the fracture parameters in two examples involving stationary cracks. The results show good agreement with the reference solutions available. Next, three crack propagation problems involving multiple and branched cracks are simulated. It is found that when the crack growth increment is taken to be 0.5 h≤ da≤0.75 h, the crack growth paths converge consistently and are satisfactory.