Blades are one of the important components on aircraft engines.If they break due to vibration failure,the normal operation of the entire engine will be offected.Therefore,it is necessary to measure their natural frequ...Blades are one of the important components on aircraft engines.If they break due to vibration failure,the normal operation of the entire engine will be offected.Therefore,it is necessary to measure their natural frequency before installing them on the engine to avoid resonance.At present,most blade vibration testing systems require manual operation by operators,which has high requirements for operators and the testing process is also very cumbersome.Therefore,the testing efficiency is low and cannot meet the needs of efficient testing.To solve the current problems of low testing efficiency and high operational requirements,a high-precision and high-efficiency automatic test system is designed.The testing accuracy of this system can reach ±1%,and the testing efficiency is improved by 37% compared to manual testing.Firstly,the influence of compression force and vibration exciter position on natural frequency test is analyzed by amplitude-frequency curve,so as to calibrate servo cylinder and fourdimensional motion platform.Secondly,the sine wave signal is used as the excitation to sweep the blade linearly,and the natural frequency is determined by the amplitude peak in the frequency domain.Finally,the accuracy experiment and efficiency experiment are carried out on the developed test system,whose results verify its high efficiency and high precision.展开更多
基金supported by the National Natural Science Foundation of China (No.51975293)Aeronautical Science Foundation of China (No.2019ZD052010)Postgraduate Research & Practice Innovation Program of NUAA (No.xcxjh20230502)。
文摘Blades are one of the important components on aircraft engines.If they break due to vibration failure,the normal operation of the entire engine will be offected.Therefore,it is necessary to measure their natural frequency before installing them on the engine to avoid resonance.At present,most blade vibration testing systems require manual operation by operators,which has high requirements for operators and the testing process is also very cumbersome.Therefore,the testing efficiency is low and cannot meet the needs of efficient testing.To solve the current problems of low testing efficiency and high operational requirements,a high-precision and high-efficiency automatic test system is designed.The testing accuracy of this system can reach ±1%,and the testing efficiency is improved by 37% compared to manual testing.Firstly,the influence of compression force and vibration exciter position on natural frequency test is analyzed by amplitude-frequency curve,so as to calibrate servo cylinder and fourdimensional motion platform.Secondly,the sine wave signal is used as the excitation to sweep the blade linearly,and the natural frequency is determined by the amplitude peak in the frequency domain.Finally,the accuracy experiment and efficiency experiment are carried out on the developed test system,whose results verify its high efficiency and high precision.
文摘介绍铁路路基动态变形模量理论计算公式的推导及动态变形模量的测试原理,采用有限元软件模拟动态变形模量的测试过程,分析承载板与土体接触压力、路基动态变形模量的影响因素,并计算动态变形模量的有效测试深度.结果表明:在承载板中心一定范围内,接触压力模拟结果较理论计算值大;土体的动弹性模量对接触压力影响很小,可以忽略;路基动态变形模量测试冲击荷载作用下,土体只发生弹性变形;动态变形模量与土体动弹性模量呈线性关系,路基动态变形模量的模拟结果大于理论计算值;土体的泊松比对动态变形模量影响较小;动态变形模量有效测试深度建议取0.5~0.6 m.
