基于极限应变法的超转分析验证与应用

The validation and application of over-speed analysis using strain-based fracture criteria

关键词:  极限应变法  超转  破裂  试验  适航

Key words:  Strain-based fracture criteria  Over-speed  Burst  Test  Airworthiness

摘要:

为了提供快速提高轮盘超转破裂裕度方法，满足适航对超转相关要求，基于极限应变法开展了轮盘超转分析和试验验证。轮盘破裂转速分析与试验结果符合性较好，轮盘起始破裂位置、应力应变分布特征通过轮盘碎片断口及残余变形获得了验证。根据轮盘起始破裂位置，给出了适航超转要求中最不利尺寸公差的确定方法和通过局部结构强化提高轮盘破裂转速的方法。分析和试验结果的对比证明了极限应变法用于超转破裂分析的合理性，整个过程也为充分利用超转试验结果对分析进行验证提供了范例，提出的提高轮盘破裂裕度方法和最不利尺寸公差确定方法具有较强操作性，可为航空发动机轮盘超转设计和适航取证提供参考。

Abstract:

In order to quickly improve disk burst margin and comply with airworthiness requirements on rotor over-speed, a disk over-speed behavior is analyzed using strain-based fracture criteria and the related test is carried out. The calculated burst speed has a good correlation with test result, the analysis on crack initiation point and stress/strain distribution are proved by disk burst fragments’ form and deformation. Based on crack initiation point, a method to define the most detrimental dimension tolerance in airworthiness regulation is shown and a method to improve disk burst margin by reinforcing local structure is introduced. The use of strain-based fracture criteria on over-speed analysis is proved to be rational by the comparison of calculation and test results. The whole process also gives a good example for fully exploring burst test results to verify the over-speed analysis, and the proposed methods could be referred to for both aero-engine design and airworthiness certification.