单点激光连续扫描测振的薄壁圆筒件模态测试

针对薄壁圆筒构件模态测试的需求,提出了基于单点激光连续扫描测振的薄壁圆筒构件模态测试方法。根据纯模态分析理论,在研究两端固定细弦自由振动的基础上,理论上建立了单点激光测振仪在两端固定的自由振动细弦上做连续扫描所得的振动信号和弦的模态振型之间的关系,研究了并提出了激光测振仪输出信号的处理方法。搭建了单点激光连续扫描测振的薄壁圆筒构件模态测试平台,对薄壁圆筒构件进行了模态实测,获得了薄壁圆筒构件前五阶固有频率和相应的模态振型,并对测试结果进行了有限元模态分析验证。结果表明,模态振型一致,固有频率误差在5%以内,证明了提出方法的正确性和有效性。

Modal Testing Method for Thin-Sheet Cylinder Parts Based on Single-Point Laser Continuous Scanning Vibrometry

Aiming at the requirements of modal testing for thin-sheet cylinder parts, a modal testing method for thin-sheet cylinder parts based on single-point laser continuous scanning vibrometry is proposed. According to normal modal analysis theory, the relationship between the vibration displacement signal which is obtained by continuous scanning the free vibration string whose both ends are fixed with single point laser vibrometer and the modal shapes of the string is established theoretically based on the investigation of free vibration of a string whose both ends are fixed. The processing approach for output of laser vibrometer is investigated. A modal testing platform for thin-sheet cylinder parts based on single-point laser continuous scanning vibrometry is built, and experimental testing for thin-sheet cylinder parts is done. The former five natural frequencies and its corresponding vibration mode are obtained. The testing results are verified by finite element modal analysis. The results show that the corresponding vibration modes are the same and natural frequency errors are less than 5%, so the proposed method is feasible and effective.