增压锅炉耐火砖疲劳裂纹扩展特性研究

Fatigue crack propagation characteristics of refractory brick in supercharged boilers

基于陶瓷材料断裂力学理论,将影响疲劳裂纹应力强度因子的裂纹尺寸作为评价耐火砖安全使用的依据,通过研究陶瓷材料裂纹扩展的一般规律,建立了耐火材料的裂纹扩展模型,逐一计算两个影响因素对于裂纹应力强度因子的影响,得到裂纹尺寸与应力强度因子的关系曲线,可得出在一定范围内,裂纹应力强度因子随裂纹尺寸的增加而增加,但随后会逐渐降低,由此可预估含裂纹缺陷耐火砖的剩余使用寿命。

Based on the fracture mechanics theory of ceramics,the fracture sizes which influence the fatigue crack stress intensity factor were taken as the criterion to evaluate the safety of refractory bricks, and a crack propagation modal was established by studying the general crack propagation rule of ceramic mate- rials. The two fracture sizes of the crack stress intensity factor were calculated separately~ the relation curves of crack stress intensity factor as a function of each fracture size were obtained. It is concluded that in a special scope,the crack stress intensity factor increases with the fracture sizes rising, and then de- creases subsequently. This may predict the residual service life of the refractory bricks.