Progressive failure analysis of unidirectional composites through mean-field homogenization and mixed-mode phase field fracture approach

Date

2024-3

Author

Atasoy, Mert

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This study introduces a new mixed-mode phase-field model for brittle fracture built upon Miehe et al.’s AT2 phase-field method with strain threshold definition. The proposed method offers results independent of the crack band width parameter. It is applied in conjunction with mean-field homogenization to characterize unidirectional composite materials from micro to macro scales, enabling the successful analysis of micro-structures. By addressing challenges related to heterogeneous models and highlighting the related geometrical limitations, the model ensures consistent results, even for micro models with high fiber volume fractions. The findings emphasize the importance of employing periodic boundary conditions on the phase-field domain, particularly in scenarios involving mixed loading conditions, to ensure accurate and realistic failure mode predictions. Furthermore, the study presents applications of the mixed-mode phase-field model in analyzing multi-fiber micro-structures under com- pression loads. The results indicate a closer agreement with experimental outcomes compared to existing studies. The development of a failure envelope using the pro- posed method, supported by extensive randomly generated data set, demonstrates its effectiveness in predicting failure in composite materials. The resulting failure model, though relatively conservative with respect to traditional failure models, demonstrates promising results in benchmark applications, highlighting its potential in engineering applications.

Subject Keywords

Finite Elements, Multi-Scale Analysis, Mixed-Mode, Phase-Field, Fracture Mechanics

URI

https://hdl.handle.net/11511/109206

Collections

Graduate School of Natural and Applied Sciences, Thesis