基于扩展有限元的陶瓷复合材料多重增韧机制

为了提高陶瓷材料的断裂韧性和可靠度，改善材料抵御破坏的能力，将优化的多重增韧机制应用到氧化铝基陶瓷材料的开发中。相变增韧机制可以耗散部分能量，降低裂纹尖端处的应力集中程度，阻止或延缓裂纹扩展速率。当增强相分布较为合理、材料的致密度较高时，裂纹偏转与桥接增韧机制可以有效地削弱裂纹扩展动力，提高材料的断裂韧性。利用扩展有限元（X-FEM）手段讨论了裂纹扩展问题，为分析陶瓷复合材料的多重增韧机制提供了新思路。

Multiple toughening mechanisms of ceramic composites based on X-FEM method

In order to improve the fracture toughness, reliability and the ability of resisting damage of the ceramic materials, appropriate multiple toughening mechanisms were introduced in alumina matrix ceramic materials. Phase transformation toughening can consume some energy, reduce the concentration of stress at the crack tip and prevent or delay the crack growth rate. When the distribution of reinforced phase is reasonable and the relative density is high, there are crack deflection and bridging forms in the crack propagation, which can weaken the crack extension power, and improve the fracture toughness of the material. The crack propagation was discussed based on extended finite element (X-FEM) method, which provides a new way for the analysis of the multiple toughening mechanisms of ceramic matrix composites.