Yuanjun Dai^1,2,*, Xin Wei¹, Baohua Li¹, Cong Wang¹, Kunju Shi¹

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.2, pp. 337-348, 2024, DOI:10.32604/fdmp.2023.042434

Abstract To study the impact of the trailing-edge wear on the vibrational behavior of wind-turbine blades, unworn blades and trailing-edge worn blades have been assessed through relevant modal tests. According to these experiments, the natural frequencies of trailing-edge worn blades −1, −2, and −3 increase the most in the second to fourth order, the fifth order increases in the middle, and the first order increases the least. The damping ratio data indicate that, in general, the first five-order damping ratios of trailing-edge worn blades −1 and trailing-edge worn blades −2 are reduced, and the first five-order damping ratios of trailing-edge worn… More >

Deborah Fowler¹, Garrett Lopp², Dhiraj Bansal³, Ryan Schultz⁴, Matthew Brake⁵, Micah Shepherd⁶

Sound & Vibration, Vol.52, No.3, pp. 12-17, 2018, DOI:10.32604/sv.2018.03864

Abstract Acoustoelastic coupling occurs when a hollow structure’s in-vacuo mode aligns with an acoustic mode of the internal cavity. The impact of this coupling on the total dynamic response of the structure can be quite severe depending on the similarity of the modal frequencies and shapes. Typically, acoustoelastic coupling is not a design feature, but rather an unintended result that must be remedied as modal tests of structures are often used to correlate or validate finite element models of the uncoupled structure. Here, however, a test structure is intentionally designed such that multiple structural and acoustic modes are well-aligned, resulting in… More >

Brian Schwarz, Patrick McHargue, Mark Richardson

Sound & Vibration, Vol.52, No.2, pp. 1-6, 2018, DOI:10.32604/sv.2018.03637

Abstract In this paper, we show how Operating Deflection Shapes (ODS’s) and mode shapes can be obtained experimentally from measurements that are made using only two sensors and two short wires to connect them to a multi-channel acquisition system. This new test procedure is depicted in Figure 1. Not only is the equipment required to do a test much more cost effective, but this method can be used to test any sized test article, especially large ones.
The testing method introduced here involves moving a pair of sensors along together in a prescribed manor, and calculating the Transmissibility between them. The… More >