火箭推进2024，Vol.50Issue(6)：98-106,9.DOI:10.3969/j.issn.1672-9374.2024.06.008
联合运动放大和3D-DIC技术识别发动机管路的高阶三维振型
High frequency 3 D mode shapes characterization of engine pipelines using motion amplification and 3 D-DIC technique
闫松 1张晓光 2张志伟1
作者信息
- 1. 航天液体动力全国重点实验室,陕西 西安 710100||西安航天动力研究所,陕西 西安 710100
- 2. 西安航天动力研究所,陕西 西安 710100
- 折叠
摘要
Abstract
Understanding the modal characteristics of the pipelines in liquid rocket engines is crucial for their fatigue-resistant design.Due to the high excitation frequency of the engine,the structural displacement amplitude generated by the corresponding high-frequency mode shape is usually very small,which is often masked by the background noise of the measurement system.A new approach of magnifying the vibration videos captured by a stereo camera under fixed-frequency excitation was adopted.Subsequent three-dimensional digital image correlation(3D-DIC)analysis of the magnified image sequences enables the identification of structural displacements from displacements below the system's background noise level,achieving accurate measurement of high-order three-dimensional modes of the structure.Under appropriate magnification multiples,problems such as the deterioration of the correspondence of speckle images due to motion magnification and subsequent failure of 3D-DIC calculations did not occur.A micro-vibrator was used to excite a cantilever beam at the first three natural frequencies.The first three out-of-plane modes of the cantilever beam from displacement responses below the background noise was obtained.These results highly agree with the modes obtained using 3D scanning laser doppler vibrometer(3D-SLDV)technique.Moreover,this technique was successfully applied to the high-order three-dimensional modal identification of actual liquid rocket engine pipelines,yielding modal results for three spatial components.This method combines the intuitiveness of motion amplification and the quantitative analysis advantages of 3D-DIC.It shows application value for three-dimensional modal analysis of key engine structures under low-magnitude sinusoidal excitation.关键词
3D-DIC/运动放大/高阶模态/液体火箭发动机Key words
3D-DIC/motion amplification/higher-order modes/liquid rocket engine分类
航空航天引用本文复制引用
闫松,张晓光,张志伟..联合运动放大和3D-DIC技术识别发动机管路的高阶三维振型[J].火箭推进,2024,50(6):98-106,9.
