博士论文答辩：基于断裂相场法的纤维增强复合材料疲劳断裂数值模拟
日期：2025/11/28 – 2025/11/28
博士论文答辩：基于断裂相场法的纤维增强复合材料疲劳断裂数值模拟
主讲人：Zhao Yonghui, Ph.D. candidate at SJTU Global College
时间：2025年11月28日（周五）上午10:00-12:00
地点：龙宾楼414B会议室
讲座摘要
Fatigue failure is a critical concern for the engineering materials and structures. As a prominent class of engineering materials, Fiber-reinforced composites (FRCs) are playing an increasingly important role in engineering applications due to their exceptional mechanical properties. However, these materials are also susceptible to fatigue failure. In this dissertation, the phase field model for fracture is adopted to study the fatigue failure problems of FRCs. However, due to the complex material properties of FRCs, the crack evolution, especially fatigue crack propagation, becomes extremely complex.
Besides, the phase field model for fatigue suffers from high computational costs for cycle-by-cycle fatigue failure simulation. Additionally, the staggered scheme, one of the most widely used solution strategies, sometimes requires many iterations between the fields, also leading to high computational costs. These issues greatly hinder the application of phase field model to fatigue failure of FRCs.
To address these challenges, this dissertation investigates the convergence behavior of the staggered scheme and proposes an efficient scheme to accelerate the simulations of the pure mechanical fatigue failure and thermal-mechanical coupled fatigue failure for FRCs.
Firstly, the author investigates the convergence behavior of staggered schemes in multi-field coupled problems and reveals that a parameter coined the degree of coupling (DOC) is the deciding factor for the convergence behaviors of the staggered scheme. When the DOC is close to zero, the staggered scheme quickly converges; when the DOC is less than but close to one, the convergence is slow; when the DOC is greater than or equal to one, the staggered scheme is not guaranteed to converge. Furthermore, given that multi-field coupled problems often involve multiple staggered schemes, this study would be able to provide guidance for scheme selection.
Secondly, the author develops an acceleration scheme for the phase field fatigue failure simulation of FRCs based on the time-scale homogenization scheme. This scheme effectively captures the mechanical responses at individual loading cycles while maintaining computational efficiency within acceptable error bounds. The proposed model successfully simulates both inter-laminar and intra-laminar fatigue failure in 3D multi-ply laminates.
Finally, the author extends the acceleration framework to thermal-mechanical coupled fatigue problems. Through DOC analysis, the optimal scheme for this three-field coupled problem is selected. Numerical experiments demonstrate that the proposed acceleration scheme achieves speed improvements exceeding an order of magnitude. Additionally, the extend model retains its capability to simulate complex failure modes in 3D multi-ply laminates.
主讲人介绍
Zhao Yonghui earned his Bachelor’s in Traffic Engineering and Master’s degrees in Mechanical Engineering from Northwestern Polytechnical University (NWPU). In 2021, he began his doctoral studies at the Shanghai Jiao Tong University (SJTU), specializing in Mechanics. His research focuses on phase field model for fracture, multi field coupled fracture, and fatigue cracking in fiber reinforced composite materials. Zhao’s research work has been published in the international journal Computer Methods in Applied Mechanics and Engineering (CMAME).