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Experimental and numerical crack analysis of mixed-mode failure in concrete by acoustic emission and boundary element method

1999; Elsevier BV; Volume: 13; Issue: 1-2 Linguagem: Inglês

10.1016/s0950-0618(99)00008-2

1879-0526

Masayasu Ohtsu, Yuki Kaminaga, Muzo C. Munwam,

Geophysical Methods and Applications

Crack extension of mixed-mode in concrete is studied by applying the acoustic emission (AE) and the boundary element method (BEM). The theory of AE wave motions is briefly reviewed, including the historical development. AE waveforms are generated as elastic waves in concrete due to crack nucleation, and can be synthesized by the integral formulation, consisting of the spatial derivatives of Green's functions, the moment tensor, and the source-time function. Kinematics of cracks are represented by the moment tensors, which can be determined by a SiGMA (simplified Green's function for moment tensor analysis) code. In bending tests of notched beams, the crack extension of mixed-mode failure in concrete is studied. Crack traces are analyzed by the two-domain BEM, based on the maximum circumferential stress criterion by Erdogan-Sih, and are in remarkable agreement with those of tested beams. Then, locations, types, and orientations of AE sources are analyzed by the SiGMA to investigate crack kinematics in the fracture process zone. Furthermore, it is attempted to estimate the normalized stress intensity factors KI*=KI/KIC and KII*=KII/KIC.