| Author: | Tong, Xu |
| Title: | Crystal plasticity finite element method-based simulation and analysis of size effects in meso/micro-scaled metal-forming |
| Advisors: | Fu, Mingwang (ME) |
| Degree: | Ph.D. |
| Year: | 2025 |
| Department: | Department of Mechanical Engineering |
| Pages: | xii, 178 pages : color illustrations |
| Language: | English |
| Abstract: | The manufacturing sector is experiencing a significant trend towards product miniaturization, particularly within industries such as automobile, medical instruments, and consumer electronics. To fulfil this demand, meso/microforming has emerged as a promising method for producing miniaturized parts and components. However, challenges related to product quality assurance and process control persist, largely due to the size effect (SE) that influences deformation mechanisms and behaviours in meso/microforming. In tandem with this, This PhD thesis is focused on studying the SE and its induced forming phenomena in micro/meso-scaled metal-forming of complex-shaped parts by Crystal Plasticity Finite Element Method (CPFEM) based simulations. The study begins by validating the feasibility of CPFEM for simulating simple meso/microforming processes through the comparisons with experimental data. This ensures the accuracy of CPFEM simulation accuracy in predicting deformation behavior, load-stroke relationships, and microstructural changes. Subsequently, the application of CPFEM is extended to more complex forming processes, such as progressive microforming and multi-step forming operations. The research revealed that CPFEM's capability to predict deformation and failure mechanisms in these forming processes, addresses a significant gap in current knowledge. Secondly, a comparative analysis of CPFEM with other common simulation methods is done in terms of the evaluation of their respective strengths and weaknesses, in terms of prediction accuracy, computational efficiency, and microstructural evolution. The integration of CPFEM with advanced experimental techniques, such as the quasi-in-situ Electron Backscatter Diffraction (EBSD), provides a comprehensive approach to understanding deformation mechanisms and microstructural changes influenced by grain SEs. The findings demonstrate CPFEM's effectiveness in capturing detailed material behaviours and deformation mechanisms. This work not only establishes a basis that CPFEM is a superior simulation tool to offer actionable insights for optimizing forming processes and selecting appropriate materials. Future research directions include enhancing computational efficiency, integrating multi-physics models, advancing fracture modelling, developing material databases, optimizing processes, and implementing in-situ and real-time monitoring. In summary, this thesis significantly advances the application of CPFEM in meso/microforming processes. Through meticulous simulations, experiments, and result comparisons, it demonstrated the CPFEM's unparalleled ability to capture detailed material behaviours and deformation mechanisms influenced by SEs. The insights gained hold substantial promise for enhancing the accuracy, efficiency, and reliability of forming complex-shaped components at the meso/micro-scale, facilitating the way for future innovations in micro-manufacturing. |
| Rights: | All rights reserved |
| Access: | open access |
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