飞机鸟撞试验瞬时速度的连续测试方法研究

Research for the Instantaneous Velocity Measurement in Aircraft Bird-Impact Test

目前速度的测试方法一般仅能确定运动物体在两点间的平均速度,瞬时速度的连续测试方法在国内尚未得到开发和应用。本文介绍一种低成本、高精度、高可靠性的连续非接触式激光测速系统。该系统发射的一片状激光受运动鸟弹的依次阻挡后,相应的光强变化将被测出并转换为位移时间曲线,经过简单的数学运算,该系统能用来确定鸟弹速度和加速度的时间历程,因而可确定鸟弹在被测区域内任一点的瞬时速度。比较试验的结果表明该系统的测试误差小于1%。该项技术还能广泛地应用于工程材料冲击研究和其他民用领域。

Up to now,the current velocity measurement methods can only generally be used to determine the average velocity of a moving object between two points.The continuous measurement method of the instantaneous velocity has not been developed and applied yet over the country from author's knowledge.In this paper,a noncontact velocity measurement system that can determine the instantaneous velocity continuously with lowcost,highaccuracy,and goodreliability, is described.A sheet of laser beam emitted from the optical system is progressively blocked and unblocked by the moving birdshell.The corresponding variation of output voltage due to the change of total laser intensity is measured by a photo detector.A displacementtime curve can be obtained by calibrating the relationship between block position and output voltage of the photo detector.Through the use of simple mathematical operation,the birdshell velocity and acceleration histories can be determined,and therefore the birdshell instantaneous velocity at any points within the measurement range can be obtained.Finally,the accuracy of this system has been analyzed.The comparison test results show that the error of the measurement is not exceeded 1%.This method can also be applied to a wide range of engineering material impact research and other civil areas.