A single-sensor-based prediction of blade multimodal dynamic stress field variation is proposed to solve the problem that the peak stress distribution for the blade is time-varying and space-varying under multi-mode vibration.Firstly,the analytical formula of blade multi-mode superposition vibration is derived,from which the characteristics of multi-mode vibration is obtained;Secondly,the participation coefficient of each mode is obtained based on the modal frequency and shape of the blade,which are extracted through finite element modal analysis;Finally,the multi-mode excitation experiment based on the vibration table is carried out,A laser displacement sensor is used as the single-sensor-measuring point to collect the blade tip vibration displacement response,from which the multi-mode vibration parameters are decoupled and extracted.The spatial-temporal variation law of the full field dynamic stress of the blade is calculated and predicted,and four strain-gauge-monitoring points are used as a reference to compare and verify the calculation results.Results show that the predicted dynamic strains at the blade root midpoint,edge,and blade body center point are highly consistent with the measured results under different modal participation,and the relative error is less than 9％.At the same time,the spatial-temporal variation law of the dynamic stress field and the peak stress of the multimodal blade are pointed out,which verifies the effectiveness of this method.
关键词
航空发动机叶片/多模态耦合共振/动应力分析/单传感器/应力场重构
Key words
aeroengine blade/multi-mode vibration/dynamic stress analysis/single sensor/strain field reconstruction
维普
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