Development of ground vibration test based flutter emulation technique

Abstract

In demand of simpler and alternative ground flutter test, a new technique that emulates flutter on the ground has recently emerged. In this paper, an improvement of the test technique is made and verified through the experimental work. The technique utilizes general ground vibration test (GVT) devices. The key idea is to emulate the distributed unsteady aerodynamic force by using a few concentrated actuator forces; referred to as emulated flutter test (EFT) technique. The EFT module contains two main logics; namely, real-time aerodynamic equivalent force calculator and multi-input-multi-output (MIMO) force controller. The module is developed to emulate the subsonic, linear flutter on a specified target structure, which is a thin aluminum clamped-plate with aspect ratio (AR) of 2.25. In this study, doublet hybrid method (DHM) was applied to model the subsonic aerodynamic force, which restricts the application to a 2-dimensional structure. Given that, correlation of several experimental works, such as wind-tunnel flutter test, EFT using laser displacement sensor (LDS), and EFT using accelerometer, on the target structure are investigated to verify the technique. In addition to the flutter boundary, flutter mode shape and trend of aerodynamic damping effect are also presented in this work. Together with these various kinds of test results, application of more compact actuator and an accelerometer as a sensor, makes the current technique the most advanced ground flutter emulation test method.

Real-Time Ground Aeroservoelastic Test for Slender Vehicles Based on Condensed Aerodynamic Force Loading

“…Additionally, in other frequency ranges, both the amplitude and phase errors are extremely small. The force control results align with the conclusions of other researchers [18][19][20][21][22]; the closer to the elastic mode frequencies, the greater the force control error. To validate the control effectiveness of the designed partially decoupled force controller, a linear sweep signal of expected force ( e f ) was simultaneously applied to all four excitation points.…”

“…Subsequently, these condensed forces are transformed into a time-domain state-space model via rational approximation, facilitating their use in real-time ground experiments. In recent years, extensive research has been conducted on the real-time calculation of condensed aerodynamic forces in the GFT [13,[18][19][20][21][22], and these methods are also applicable to the GAT. Therefore, the theoretical details of these methods are not reiterated in this paper.…”

“…Over the subsequent years, notable advancements have been made by researchers. Wu et al [18,19], Wang et al [20], Zhang et al [21], and Yun et al [22] have significantly contributed to refining the method, focusing on aspects such as the condensation of aerodynamic forces and the design of force controllers. Collectively, these efforts have played a crucial role in advancing the effectiveness and precision of the GFT.…”

Flutter Boundary Prediction Based on Structural Frequency Response Functions Acquired from Ground Test

“…Hu et al [11], Wang and Fan [12], and Zhang et al [13] have made contributions to the GFST method in terms of condensation of aerodynamic forces, force controller design, and test error interference. For force loading, instead of an electromagnetic exciter, Yun and Ham [14,15] used a direct drive linear actuation (DDLA) motor controlled by a simple inverse dynamic method. These studies show that the most serious problem with GFST lies in the design of the force controller.…”

Cable Suspension and Balance System with Low Support Interference and Vibration for Effective Wind Tunnel Tests

“…Occasionally, a water tunnel takes its place for better Reynolds number similarity and improved flow visualization [3][4][5]. Recently, even an emulated flutter wind tunnel test was proposed [6].…”