Experimental investigation on aircraft dynamic stability parameters

Meccanica ◽  
1993 ◽  
Vol 28 (1) ◽  
pp. 61-68 ◽  
Author(s):  
Francesco Fusco ◽  
Giorgio Guglieri
Keyword(s):  
Experimental Investigation ◽  
Dynamic Stability ◽  
Stability Parameters

scholarly journals Analytical and Experimental Investigation of the Stability of the Rotor-Bearing System of a New Small Turbocharger

1987 ◽  
Author(s):  
H. R. Born
Keyword(s):  
Experimental Investigation ◽  
Dynamic Stability ◽  
Squeeze Film ◽  
Test Results ◽  
Flow Capacity ◽  
Squeeze Film Dampers ◽  
Rotor Bearing ◽  
The Stability ◽  
Turbine Design ◽  
Bearing System

This paper presents an overview of the development of a reliable bearing system for a new line of small turbochargers where the bearing system has to be compatible with a new compressor and turbine design. The first part demonstrates how the increased weight of the turbine, due to a 40 % increase in flow capacity, influences the dynamic stability of the rotor-bearing system. The second part shows how stability can be improved by optimizing important floating ring parameters and by applying different bearing designs, such as profiled bore bearings supported on squeeze film dampers. Test results and stability analyses are included as well as the criteria which led to the decision to choose a squeeze film backed symmetrical 3-lobe bearing for this new turbocharger design.

scholarly journals Experimental Investigation of Using an Electromagnetic Gearbox to Ensure Dynamic Stability

2021 ◽  
Vol 288 ◽  
pp. 01106
Author(s):  
Alexey Zhidkov ◽  
Andrey Achitaev ◽  
Elena Gracheva
Keyword(s):  
Experimental Investigation ◽  
Dynamic Stability ◽  
Rotating Machines ◽  
Flexible Coupling ◽  
The World ◽  
Physical Prototype ◽  
Fundamental Transformation

Small generation is constantly increasing both in Russia and around the world. At the same time, more and more urgent problems arise related to the loss of dynamic stability of rotating machines with low inertia of their rotors. The paper proposes one of the variants for solving this problem by fundamental transformation of the principles of small generation, taking into account the development of a flexible coupling between a turbine and a generator by using an electromagnetic gearbox instead of a connecting coupling. Investigations are carried out on a physical prototype of an electromagnetic gearbox with observation of real parameters.

Evaluation of Static and Dynamic Stability of Spinal Cord Injuries: What Are the Gaps

2020 ◽  
Vol 22 (1) ◽  
pp. 1-5
Author(s):  
Hussein Asiabi ◽  
Mokhtar Arazpour ◽  
Mahmoud Bahramizadeh ◽  
Mohammad Taghi Karimi
Keyword(s):  
Spinal Cord ◽  
Dynamic Stability ◽  
Normal Subjects ◽  
Assistive Devices ◽  
Quiet Standing ◽  
Stability Parameters ◽  
Cord Injury ◽  
Lesion Level ◽  
The Stability ◽  
Improve Stability

Background. Depending on the level of lesion, spinal cord injury (SCI) individuals have limited ability to stand and walk. They have to use various assistive devices to restore their abilities. The aim of this study was to evaluate the stability of SCI individuals during walking and quiet standing. Material and methods. Three groups: normal subjects and SCI individuals with complete and incomplete lesions, were enrolled. Stability of the subjects was evaluated based on center of pressure (COP) sways in quiet standing and spatiotemporal gait parameters in walking. The difference between the stability of normal and SCI subjects was determined by use of the two-sample t test. The correlation between the mean values of stability parameters in standing and walking and lesion level was determined by use of Pearson’s correlation. Results. The stability of SCI subjects during quiet standing was better than that of normal subjects. How­ever, their dynamic stability was significantly less than normal subjects. The dynamic stability of complete and incomplete SCI subjects did not differ significantly (P-value<0.05). There was no correlation between lesion level and stability parameters. Conclusion. 1. SCI individuals suffer mostly from lack of dynamic stability, which does not depend on their lesion levels. 2. It seems that this problem may be due to rehabilitation methods used to improve stability in these patients. 3. It is recommended that new methods of rehabilitation or assistive devices should be used to improve stability of these individuals.

scholarly journals Unsteady Vibration Aerodynamic Modeling and Evaluation of Dynamic Derivatives Using Computational Fluid Dynamics

2015 ◽  
Vol 2015 ◽  
pp. 1-15 ◽  
Author(s):  
Xu Liu ◽  
Wei Liu ◽  
Yunfei Zhao
Keyword(s):  
Dynamic Stability ◽  
Time Domain ◽  
System Modeling ◽  
Aircraft Design ◽  
Experimental Simulation ◽  
Experimental Result ◽  
Calibration Model ◽  
Stability Parameters ◽  
Slender Body Theory ◽  
Vibration Model

Unsteady aerodynamic system modeling is widely used to solve the dynamic stability problems encountering aircraft design. In this paper, single degree-of-freedom (SDF) vibration model and forced simple harmonic motion (SHM) model for dynamic derivative prediction are developed on the basis of modified Etkin model. In the light of the characteristics of SDF time domain solution, the free vibration identification methods for dynamic stability parameters are extended and applied to the time domain numerical simulation of blunted cone calibration model examples. The dynamic stability parameters by numerical identification are no more than 0.15% deviated from those by experimental simulation, confirming the correctness of SDF vibration model. The acceleration derivatives, rotary derivatives, and combination derivatives of Army-Navy Spinner Rocket are numerically identified by using unsteady N-S equation and solving different SHV patterns. Comparison with the experimental result of Army Ballistic Research Laboratories confirmed the correctness of the SHV model and dynamic derivative identification. The calculation result of forced SHM is better than that by the slender body theory of engineering approximation. SDF vibration model and SHM model for dynamic stability parameters provide a solution to the dynamic stability problem encountering aircraft design.

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