| 1. |
- Hesammokri, Parnian, et al.
(author)
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An extended hydrostatic-deviatoric strain energy density decomposition for phase-field fracture theories
- 2023
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In: International Journal of Solids and Structures. - : Elsevier. - 0020-7683 .- 1879-2146. ; 262-263
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Journal article (peer-reviewed)abstract
- The interest in using phase-field theories to numerically analyze fracture has sky-rocketed in the last years. However, in phase-field fracture models are splits, or decompositions, of the strain energy density vital to avoid interpenetration of crack surfaces and to select physically trustworthy crack paths. The most popular decomposition strategies use either a spectral decomposition or a hydrostatic-deviatoric decomposition. Both decompositions have significant disadvantages; the most important is that none of them can handle mixed -mode load scenarios in compression. To circumvent these problems, a generalized decomposition method is derived that unifies some features of the hydrostatic-deviatoric and spectral decompositions, enhanced with a classical Mohr-Coulomb failure criterion. The derived decomposition scheme has the potential to judge whether or not a compressive deformation field will assist in the crack driving process in brittle materials. The enhanced decomposition is scrutinized in numerical models and revealing biaxially loaded crack experiments in global compression. Simulations using the decomposition scheme capture the experiments in a remarkable way: complex crack patterns are reproduced, as well as critical loads. The enhanced decomposition strategy hence provides mechanistic insight into fracture processes in brittle materials subject to mixed-mode loads.
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| 2. |
- Hesammokri, Parnian, et al.
(author)
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Numerical analyses of brittle crack growth experiments in compression using a modified phase-field theory
- 2024
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In: International Journal of Solids and Structures. - : Elsevier. - 0020-7683 .- 1879-2146. ; 296
-
Journal article (peer-reviewed)abstract
- There has been a huge interest in recent years in using phase -field theories for numerical analyses of fracture phenomena. However, in phase -field fracture theories, a critical aspect often involves a decomposition of the strain energy density to select physically trustworthy crack paths and to prevent interpenetration of crack surfaces. This aspect becomes even more critical in the case of mixed -mode loading under compression. To overcome these challenges, a hydrostatic-spectral-deviatoric decomposition, enhanced by separate critical energy release rates for different fracture modes, is employed in this study. In order to evaluate the enhanced decomposition strategy, a set of biaxially loaded crack experiments in global compression is designed. Samples of different geometries contain multiple flaws and holes. The experiments are numerically simulated using a unified set of material parameters and three different strain energy decomposition methods (i.e., hydrostaticspectral-deviatoric, spectral and hydrostatic-deviatoric). Simulations using the hydrostatic-spectral-deviatoric decomposition scheme capture both intricate crack paths and critical loads in the experiments. The enhanced decomposition strategy seems capable of simulating the experiments with reasonable precision, in sharp contrast to the two commonly used decomposition strategies (spectral and hydrostatic-deviatoric).
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