Symmetric-Galerkin boundary element transient analysis of the DSIFs for the interaction of a crack with a circular inclusion

Journal Article · Sat Jan 01 04:00:00 EST 2011 · Key Engineering Materials

OSTI ID:986405

Phan, Anh-Vu ^[1]; Gray, Leonard J ^[1]; Salvadori, Alberto ^[1]

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1. ORNL

A dynamic analysis of crack-inclusion interaction is described in this paper. The analysis employs a two-dimensional symmetric-Galerkin boundary integral formulation for multi-domain elastodynamic fracture analysis in the frequency domain. The multi-domain technique is based on the assumption of perfectly bonded inclusions. The numerical implementation of this boundary integral formulation is carried out with standard quadratic elements, allowing the use of an improved quarter-point element for accurately determining frequency responses of the dynamic stress intensity factors (DSIFs). To deal with singular and hypersingular integrals, the formulation is decomposed into two parts: the rst part is identical to that for elastostatics while the second part contains at most logarithmic singularities. The treatment of the elastostatic singular and hypersingular singular integrals employs an exterior limit to the boundary, while the weakly singular integrals in the second part are handled by Gauss quadrature. Time histories (transient responses) of the DSIFs are obtained in a post-processing step by applying the fast Fourier transform (FFT) and inverse FFT to the frequency responses of these DSIFs. Two numerical examples are presented for the computation of the DSIFs due to crack-inclusion interaction under two types of impact loading: Heaviside step loading and blast loading. The numerical results are consistent and con rm the well known crack tip shielding mechanism observed during the interaction between a crack and a much stiffer inclusion.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 986405
• Journal Information: Key Engineering Materials, Journal Name: Key Engineering Materials Vol. 545; ISSN 1013-9826; ISSN KEMAEY
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
FRACTURES
IMPLEMENTATION
QUADRATURES
SHIELDING
STRESS INTENSITY FACTORS
TRANSIENTS