为了分析研究某型燃气轮机封严盘均压孔裂纹故障,达到提高疲劳寿命的目的,进行了封严盘故障机理和局部结构修改分析.建立封严盘有限元分析模型,分析了封严盘振动应力分布特点和共振特性,结果表明:均压孔孔边应力水平高是疲劳裂纹的主要原因,针对该原因提出了改进方向.在装配状态下,针对原结构以及均压孔部位进行局部修改的几种情况进行了结构强度对比分析,最终提出了某型燃气轮机封严盘局部结构修改方案,修改后均压孔孔边的应力水平降低16%,屈服强度储备系数由0.891提高到1.069. In order to analyze and study the cracks of the pressure plate cracks in the sealing plate of a gas turbine and to improve the fatigue life, the failure mechanism of the sealing plate and the modification of the local structure were analyzed. The finite element model of the sealing plate was established, The results show that the main reason of the fatigue crack is the high stress level at the edge of the pressure equalizing hole, and the improvement direction is put forward for this reason.At the assembly state, the local structure and the part of the pressure equalizing hole are modified locally Finally, a modified scheme of partial structure of sealing plate of a gas turbine is proposed. The stress level of the equalizing hole decreases by 16% and the yield strength reserve coefficient increases from 0.891 to 1.069.