基于有限元法的发动机二级从动齿轮疲劳裂纹故障分析研究

Research on Failure Analysis of Secondary Driven Gear of Turboprop Engine Based on Finite Element Method

为研究涡桨发动机减速器齿轮传动组件的疲劳失效机理,以提高其工作可靠性及使用寿命,开展减速器桨轴组件的高低周复合疲劳试验。结果显示,二级从动齿轮陪试件卡槽处出现沿齿轮轴子午面扩展的疲劳裂纹。为了进一步明确疲劳裂纹产生的机理,建立桨轴组件三维有限元模型,利用有限元软件Ansys对试验条件下二级从动齿轮陪试件进行应力计算,根据计算结果分析影响陪试件卡槽应力状态的各个因素及其影响规律。结果表明:装配过盈量和卡槽倒圆尺寸是造成陪试件卡槽应力过大的主要因素。最后基于数值模拟分析结果提出改进措施,为故障排除提供有力依据。

In order to study the fatigue failure mechanism of the driven gear component,a high-low cycle complex fatigue test was conducted on a turboprop engine propeller-shaft reducer component aiming for improving its working reliability and service life.The result shows that the fatigue crack initiated at the groove of the secondary driven gear test piece and propagated along the meridian plane of the shaft.To further analyze the mechanism of fatigue crack,a three-dimensional finite element model of the propeller-shaft assembly was established.The finite element software Ansys was used to calculate the stress of the secondary driven gear under the test conditions.The influence factors and law on the stress state of the groove has also been analyzed according to the calculation result.It is found that the magnitude of assembling interference and the size of fillets are the main reasons that affect the stress state of the groove.Finally,based on the result of the finite element analysis,suggestions and improvement measures are put forward,which provide an effective basis for failure analysis.