scholarly journals Developing uncertainty models for robust flutter analysis using ground vibration test data

2001 ◽  
Author(s):  
Starr Potter ◽  
Rick Lind
Keyword(s):  
Test Data ◽  
Ground Vibration ◽  
Vibration Test ◽  
Flutter Analysis ◽  
Uncertainty Models

Comparison of flutter calculation methods based on ground vibration test result

2019 ◽  
Vol 91 (3) ◽  
pp. 466-476
Author(s):  
Wojciech Chajec
Keyword(s):  
Low Cost ◽  
Ground Vibration ◽  
Control Surface ◽  
Vibration Test ◽  
Problem Solution ◽  
Lattice Method ◽  
Mass Model ◽  
Content Type ◽  
Strip Theory ◽  
Flutter Analysis

PurposeA low-cost but credible method of low-subsonic flutter analysis based on ground vibration test (GVT) results is presented. The purpose of this paper is a comparison of two methods of immediate flutter problem solution: JG2 – low cost software based on the strip theory in aerodynamics (STA) and V-g method of the flutter problem solution and ZAERO I commercial software with doublet lattice method (DLM) aerodynamic model and G method of the flutter problem solution. In both cases, the same sets of measured normal modes are used. Design/methodology/approachBefore flutter computation, resonant modes are supplied by some non-measurable but existing modes and processed using the author’s own procedure. For flutter computation, the modes are normalized using the aircraft mass model. The measured mode orthogonalization is possible. The flutter calculation made by means of both methods are performed for the MP-02 Czajka UL aircraft and the Virus SW 121 aircraft of LSA category. FindingsIn most cases, both compared flutter computation results are similar, especially in the case of high aspect wing flutter. The Czajka T-tail flutter analysis using JG2 software is more conservative than the one made by ZAERO, especially in the case of rudder flutter. The differences can be reduced if the proposed rudder effectiveness coefficients are introduced. Practical implicationsThe low-cost methods are attractive for flutter analysis of UL and light aircraft. The paper presents the scope of the low-cost JG2 method and its limitations. Originality/valueIn comparison with other works, the measured generalized masses are not used. Additionally, the rudder effectiveness reduction was implemented into the STA. However, Niedbal (1997) introduced corrections of control surface hinge moments, but the present work contains results in comparison with the outcome obtained by means of the more credible software.

scholarly journals Minimization of Ground Vibration Test Configurations for F-16 Aircraft by Subtractive Modification

2019 ◽  
Vol 2019 ◽  
pp. 1-19 ◽  
Author(s):  
Sertac Koksal ◽  
Erdinc Nuri Yildiz ◽  
Yigit Yazicioglu ◽  
Gokhan Osman Ozgen
Keyword(s):  
Structural Model ◽  
Ground Vibration ◽  
Aircraft Design ◽  
Vibration Test ◽  
Fe Model ◽  
Certification Process ◽  
Critical Configurations ◽  
Flutter Analysis ◽  
Primary Test ◽  
Coarse Model

The certification process of external loads designed for aircraft needs to satisfy various criteria where compatibility with existing systems is one of the essential requirements. Flight flutter testing is a critical part of a certification process that requires many preliminary studies. Computational flutter analysis must precede actual flutter test to determine an approximately safe flight envelope to ensure the safety of the personnel and aircraft. To be able to perform flutter analysis of an aircraft, an accurate structural model such as finite element (FE) model is required. An accurate FE model can be obtained from a coarse model using ground vibration test (GVT) which is also the primary test campaign for certification of a new external load, new aircraft design, or modification on existing aircraft. On the other hand, performing GVT for each configuration of an aircraft is both time consuming and costly. It would be more practical to determine the critical configurations for an aircraft using computational tools and perform actual GVT for those configurations. The objective of this study is to simulate GVT characteristics for downloading and fuel configurations of F-16 aircraft. A novel methodology is proposed where various loading configurations can be simulated by subtractive modification from loaded GVT data so that joint stiffnesses between stores and aircraft need not be identified. The proposed technique decreases the number of necessary physical GVT testing campaigns.

The Dynamic Response of Zhengyangmen Gate Tower Induced by Beijing Metro Line 2

2014 ◽  
Vol 580-583 ◽  
pp. 1212-1217
Author(s):  
Qi Song ◽  
Jia Qi Guo ◽  
Wen Hua Chen ◽  
Ping Guo
Keyword(s):  
Dynamic Response ◽  
Dynamic Analysis ◽  
Test Data ◽  
Vibration Test ◽  
Analysis Model ◽  
Response Characteristics ◽  
The North ◽  
Cultural Relic ◽  
Dynamic Response Characteristics ◽  
South Axis

Zhengyangmen gate tower is a national emphasis cultural relic unit along the north-south axis of Beijing, which is above the Beijing metro line 2. Based on dynamic analysis model of gate tower and the position of gate tower and subway, the dynamic response characteristics of gate tower induced by Beijing metro line 2 are calculated, and compared with the in-site vibration test data.

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