Asundi Anand, Singh Vijay Raj
School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore.
Appl Opt. 2006 Apr 10;45(11):2391-5. doi: 10.1364/ao.45.002391.
Time-averaged in-line digital holography is applied for vibration analysis. In particular, by use of a double-exposure approach, simultaneous determination of vibration mode shape and mean static state deformation during a vibration cycle are obtained. The subtraction of two numerically reconstructed digital holograms recorded at the same resonant frequency but with a small difference in amplitude shows the mixing of Bessel-type time-averaged fringes owing to vibration and of the double-exposure fringes owing to differences in the mean deformation of the object. It is shown that separation of these fringe patterns can be readily accomplished numerically. An experimental demonstration of this effect by use of in-line digital holography for relatively small membranes is demonstrated.
时间平均同轴数字全息术被应用于振动分析。特别是，通过使用双曝光方法，可以同时获得振动模式形状和振动周期内平均静态变形的信息。对在相同共振频率下记录但振幅略有差异的两个数字全息图进行数值重建后相减，结果显示了由于振动产生的贝塞尔型时间平均条纹与由于物体平均变形差异产生的双曝光条纹的混合。结果表明，这些条纹图案的分离可以很容易地通过数值方法实现。本文展示了使用同轴数字全息术对相对较小的膜进行这种效应的实验验证。
