Time-domain rotational angle identification of a beam structure utilizing the dynamic transverse deflection signal

• Published in: Journal of the Chinese Institute of Engineers 2008-03, Vol.31 (2), p.279-290
• Main Authors: Jenq, Syh-Tsang, Chao, Chih-Hang, Jeng, Yih-Nen, Liu, En-Cheng
• Format: Article
• Language: English
• Subjects: beam; real time signals; rotation angle identification; structure health monitoring
• ISSN: 0253-3839; 2158-7299
• DOI: 10.1080/02533839.2008.9671381

The real time signal identification of rotation angle for a beam structure is studied in this work. A laser displacement sensor traced transverse displacement signal was used to identify the rotation angle of a beam. An orthogonal polynomial approach was used to expand the transverse displacement signal into orthogonal functions and their associated coefficients. These coefficients were used to identify the orthogonally expanded coefficients associated with the rotation angles of the beam structure. The rotation angle response of the beam can finally be synthesized and checked against the finite element code predicted result. We also conducted impact hammer tests on the root of a metallic cantilever beam. Both the loading history and the transverse displacement history at a specific location on the beam specimen were recorded. Similar to the numerical synthesis process, the test determined a displacement signal can also be used to identify the rotation angle of the beam. Through numerical and experimental verification, the currently proposed analysis seems to be able to identify the dynamic rotation angle response of the beam structure closely, when the prescribed transverse displacement input signal of the beam is given.