摘要：Blades are one of the important components on aircraft *** they break due to vibration failure,the normal operation of the entire engine will be ***,it is necessary to measure their natural frequency before installing them on the engine to avoid *** present,most blade vibration testing systems require manual operation by operators,which has high requirements for operators and the testing process is also very ***,the testing efficiency is low and cannot meet the needs of efficient *** solve the current problems of low testing efficiency and high operational requirements,a high-precision and high-efficiency automatic test system is *** testing accuracy of this system can reach ±1%,and the testing efficiency is improved by 37% compared to manual ***,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 ***,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 ***,the accuracy experiment and efficiency experiment are carried out on the developed test system,whose results verify its high efficiency and high precision.

摘要：本文介绍了一种通过调整卡箍使得管道避免发生共振的设计策略.当管道的固有频率在机械设备运作时产生的振动频率范围内,会引发共振现象,给机械设备的正常操作带来严重的灾难.因此,把机械设备操作产生的振动频率范围定义为频带禁区.通常,工程中的管道被简化为多跨输流管道:通过将卡箍简化为线性和扭转刚度,建立了多跨输流管道的整体管道模型.通过采用Galerkin截断方法并应用广义特征值方法,获得了多跨输流管道的固有频率.通过对比不同长度的管道固有频率和频带禁区,定义了管长的安全范围和共振范围分别为频带禁区的外和内,并且通过分析卡箍的影响推导得出了绝对安全长度和绝对共振长度.此外,还确定了卡箍刚度和位置对安全范围的影响.结果表明,通过调整卡箍的线性刚度、扭转刚度和位置,管道的安全范围会发生显著地变化.根据这些结果,提出了一种管道设计策略,从而避免了管道的共振发生,并减少了使用卡箍的数量.最后,以飞机上的一段管道为例进行了设计,结果表明:通过调整卡箍,管道的固有频率成功地远离了频带禁区,因而在飞机的运行过程中不会发生共振.总而言之,通过调整卡箍的刚度或位置,可以获得避免多跨输流管道发生共振的设计策略.

摘要：The traditional payload attaching fitting (PAF) does not provide any vibration isolation, because of its large stiffness. Whole-spacecraft vibration isolation is a direct and effective approach to assure the successful launching and orbit insertion of a spacecraft. In view of the problems of stiffness and vibration isolation design, for which the designers care most, the study of whole-spacecraft vibration isolator (WSVI) consists of two parts. In the first part, the stiffness feature of the WSVI is studied...