Open Access Open Access  Restricted Access Subscription or Fee Access

Video motion amplification vs. operating deflection shapes for machinery diagnosis

William D Marscher, Maki M Onari

Abstract

Operating Deflection Shape (ODS) has been an important tool in visualizing the vibration of a machine and its system, including piping networks. The input for ODS is the phase-linked signal set from a group of accelerometers, moved over often hundreds of test points. The data is superimposed onto a CAD model, and then scaled-up vibration motion is animated at frequencies of interest. This process is time-consuming and therefore expensive each time it is applied by experts, and is error-prone. An alternative method has been developed that is based on evaluation of high resolution/ high speed videos. The method provides information equivalent to a high-sensor-count ODS, by treating each pixel as an accelerometer, using the pixel’s light intensity modulation to translate information embedded in the video into vibration motion able to be observed and interpreted by human investigators.

Keywords

Motion Amplification; High Speed Video; Operating Deflection Shape; Turbomachinery

Full Text:

PDF

References

Marscher, W.D., “Determination of Pump Rotor Critical Speeds During Operation through Use of Modal Analysis”, Proc ASME 1986 WAM Symposium on Troubleshooting Methods and Technology, Anaheim Cal, Dec 1986.

Marscher, W.D., “Analysis and Test of Multistage Pump Wet Critical Speeds”, ASLE/ASME Joint Tribology Conf., Ft. Lauderdale, Oct. 1989.

Jen,C.-W., and Marscher, W.D., Experimental Modal Analysis of Turbomachinery Rotors Using Time-Averaging, Proc. International Modal Analysis Conference, Orlando Florida, Jan 26, 1990.

Marscher,WD, Vibration Chapter and Predictive Maintenance Chapter, STLE Tribology & Lubrication Handbook, STLE Park Ridge IL, 1997.

Timoner, SJ, and Freeman, DM, “Multi-image gradient-based algorithms for motion estimation”, Optical Engineering 40.9 (2001) pp. 2003-2016.

Liu et al, “Motion magnification”, ACM Transactions of Graphics (TOG) – Proc. of ACM SIGGRAPH 2005, TOG Homepage, v. 24, Issue 3, July 2005.

Wu, H-Y, et al, “Eulerian video magnification for revealing subtle changes in the world”, ACM Trans. of Graphics (Proc. SIGGRAPH 2012), v. 31, August 2012.

Lerche, A.H., and Marscher, W.D., “Comparison of ODS and Motion Amplified Video Techniques”, 89th Shock and Vibration Symposium, Dallas TX, Nov. 4-8, 201.