MEMS导热薄膜热力耦合下的相场损伤建模

Phase-Field Modeling of Thermo-Mechanical Damage in MEMS Thermally Conductive Films

摘要: 随着MEMS技术向纳米尺度发展，MEMS器件在复杂多变的多物理场耦合载荷作用下，其内部预先存在的或在使用中萌生的微裂纹会发生演化，这种演化是导致器件力学性能发生不可逆劣化的主要物理机制之一。将相场理论与损伤力学相结合，针对热力耦合环境下的MEMS导热薄膜的裂纹演化行为开展了理论建模与分析。所构建的相场损伤模型能够准确描述导热材料在热应力作用下裂纹的萌生与扩展过程。该模型综合考虑了材料初始缺陷对断裂行为的影响，并引入了热力耦合边界条件下的多场交互效应。在ABAQUS平台上，基于UEL子程序的数值模拟，系统探究了不同热边界条件及初始损伤对裂纹扩展规律的影响。所建立的相场损伤模型为揭示导热材料在热力载荷下的断裂机制提供了可靠的理论框架，并通过数值仿真验证了其有效性，为未来MEMS器件的可靠性设计与性能评估提供重要的理论支撑与指导。

Abstract: With the advancement of MEMS technology towards the nanoscale, microcracks pre-existing or initiated during service in MEMS devices evolve under complex multiphysics coupled loads. This evolution is one of the primary physical mechanisms leading to irreversible degradation of the mechanical performance of the devices. By integrating phase-field theory with damage mechanics, this study conducts theoretical modeling and analysis of crack evolution in MEMS thermal conductive films under thermomechanical coupling environments. The developed phase-field damage model accurately captures the initiation and propagation of cracks in thermally conductive materials under thermal stress. The model incorporates the influence of initial material defects on fracture behavior and introduces multiphysics interaction effects under thermomechanically coupled boundary conditions. Numerical simulations based on the UEL subroutine on the ABAQUS platform systematically investigate the effects of different thermal boundary conditions and initial damage values on crack propagation behavior. The established phase-field damage model provides a robust theoretical framework for understanding the fracture mechanisms of thermal conductive materials under thermomechanical loads, validated through numerical simulations. This work offers important theoretical support and guidance for the reliability design and performance evaluation of future MEMS devices.