陶瓷材料热震裂纹几何边界效应的实验研究与数值预报

Combined with experimental, theoretical and numerical studies, the project focuses on the geometry and boundary effect of thermal shock cracking on ceramic materials. The main research contents are shown as following: (1) design the ceramic specimens with different shape (regular polygon, circle, ellipse, and circular ring) and size, conduct thermal shock experiment under different condition (initial temperature, local thermal shock), and obtain the effect of geometry and boundary on thermal shock crack pattern; (2) using high-speed camera instrument, develop the in situ observation method of thermal shock cracking, to observe the cracking initiation and propagation process, and to explore the evolution law of thermal shock crack pattern; (3) using “semi-inverse method”, inversely estimate correlative parameters at high temperatures, and study the effect of geometry, boundary, and thermal shock temperature on them; (4) combined with minimum potential energy principle, stress intensity factor method, and damage theory, develop the numerical simulation method of cracking process of ceramic materials under thermal shock, analyze the cracking mechanism, determine the concise effect law of geometry and boundary, and to achieve the quantitative numerical prediction of thermal shock cracking. The present study will provide theoretical basis and technical reserves for the guidance of thermal shock resistance of ceramic materials and structures, and for the normalized evaluation of thermal shock failure, and then promote the development of thermal mechanical coupling theory in solid mechanics.

本项目拟以系列实验为基础，结合理论和数值分析，研究陶瓷材料热震裂纹的几何边界效应。主要包含以下研究内容：设计不同形状（正多边形、圆形、椭圆、圆环等）和不同尺寸的薄片陶瓷试件，在不同热震条件下（初始温度、局部热震）进行系列热震实验，获取热震裂纹构型的几何边界效应影响规律；利用高速摄像设备，发展热震开裂的原位观测方法，动态观测热震裂纹的萌生和高速扩展过程，探索热震裂纹随时间的演化规律；利用“半逆方法”，反演相关高温参数，研究其随热震温度和几何边界效应的影响规律；结合最小势能原理、应力强度因子方法和损伤理论，发展陶瓷材料热震开裂过程的数值模拟方法，分析热震开裂机理，确定几何边界效应的简明影响规律，实现对热震裂纹的定量数值预报。当前项目为指导陶瓷材料和结构的抗热震性设计，以及热震失效的标准化评估提供理论依据和技术储备，促进固体力学热力耦合理论的发展。