scholarly journals DYNAMICS OF AN ELASTIC AIRPLANE

Aviation ◽  
2005 ◽  
Vol 9 (1) ◽  
pp. 8-13
Author(s):  
Peter Chudý ◽  
Vladimír Daněk
Keyword(s):  
Numerical Simulation ◽  
Analytical Solution ◽  
Time Domain ◽  
Aerospace Engineering ◽  
Elastic Response ◽  
Elastic Model ◽  
The Past ◽  
University Of Technology ◽  
Complex Simulation ◽  
The Time Domain

This paper presents the work performed by the Institute of Aerospace Engineering at the Brno University of Technology. The purpose of the project was to compare the results obtained from classical analytical solutions and a complex numerical simulation of an airplane's aero elastic response. Compared to the analytical solution, which reduces the entire process to a straightforward manipulation with time‐proven graphs and tables, the numerical simulation offers a more complex description of the dynamic processes. A complex simulation, in contrast to the analytical solution providing us with only one estimated parameter, allows monitoring selected quantities in the time domain, thus giving us a tool for a visual qualification of the investigated process. In the past, dynamic aeroelastic properties were estimated utilizing simplified stick beam models. The desire for more complex aero elastic simulations led to the concept of the advanced aero elastic model, coupling advanced 3D structural FEM models with proven aerodynamic theory in the form of the DLM panel method.

scholarly journals Exploring the Time Domain with Synoptic Sky Surveys

2011 ◽  
Vol 7 (S285) ◽  
pp. 141-146 ◽  
Author(s):  
S. G. Djorgovski ◽  
A. A. Mahabal ◽  
A. J. Drake ◽  
M. J. Graham ◽  
C. Donalek ◽  
...  
Keyword(s):  
Time Domain ◽  
Lessons Learned ◽  
Sky Surveys ◽  
The Past ◽  
Systematic Exploration ◽  
The Time Domain ◽  
New Research

AbstractSynoptic sky surveys are becoming the largest data generators in astronomy, and they are opening a new research frontier that touches practically every field of astronomy. Opening the time domain to a systematic exploration will strengthen our understanding of a number of interesting known phenomena, and may lead to the discoveries of as yet unknown ones. We describe some lessons learned over the past decade, and offer some ideas that may guide strategic considerations in the planning and execution of future synoptic sky surveys.

Stability Evaluations of Semi-Submersible Heavy Transport Vessels by a Progressive Flooding Simulation Tool

2012 ◽  
Author(s):  
Hendrik Dankowski ◽  
Hannes Hatecke
Keyword(s):  
Time Domain ◽  
Simulation Method ◽  
Intermediate Step ◽  
Viscous Effects ◽  
The Past ◽  
Discharge Coefficients ◽  
Damage Stability ◽  
Offshore Industry ◽  
The Stability ◽  
The Time Domain

Rising needs for heavy transport operations are intensified by the expanding offshore industry worldwide. Whenever very large and heavy objects have to be transported, only semi-submersible heavy transport vessels are capable of carrying this special cargo. Accidents in the past during operations of these vessels highlight the requirement of analyzing the operation procedures in more detail. Especially the submerging process of the main working deck is very critical regarding the hydrostatic stability. A new numerical progressive flooding simulation method will be presented for applications like accident investigations or damage stability assessments. This method is modified to fit the special requirements of simulating the operational behavior of semi-submersible vessels in the time-domain. A direct approach is chosen, which computes the flux between the compartments based on the Bernoulli equation and the current pressure heads at each intermediate step. Losses due to viscous effects are taken into account by empirical discharge coefficients. This method will be used to simulate the submerging operation in the time-domain to point out critical situations regarding the stability of the vessels and the cargo. This will be compared to accidents which occurred in the past. Furthermore, recommendations for operational procedures are proposed.

scholarly journals Response of a Light Aircraft Under Gust Loads

10.14311/556 ◽  
2004 ◽  
Vol 44 (2) ◽  
Author(s):  
P. Chudý
Keyword(s):  
Software Package ◽  
Aerospace Engineering ◽  
Structural Flexibility ◽  
Aeroelastic Response ◽  
Stochastic Nature ◽  
The Past ◽  
University Of Technology ◽  
Gust Loads ◽  
Gust Response

This project presents work performed by the Institute of Aerospace Engineering, Brno University of Technology. The primary purpose of this work was to estimate the aeroelastic response of a light aircraft under gust loads. In the past, the gust response has been investigated using the Pratt - Walker formula. This formula is derived from the response of a rigid airplane to a discrete gust. However, the Pratt-Walker formula does not capture either the stochastic nature of continuous turbulence or the effects of structural flexibility. The analysis described here was performed using the advanced FEM software package MSC Nastran.

Numerical Simulation by CGM for Moving Force Identification

2012 ◽  
Vol 238 ◽  
pp. 826-829
Author(s):  
Zhen Chen ◽  
Jun Ling Han
Keyword(s):  
Numerical Simulation ◽  
Time Domain ◽  
Bending Moment ◽  
Identification Accuracy ◽  
Time Varying ◽  
Acceptable Solution ◽  
Moving Force ◽  
Ill Posed ◽  
Simulation Results ◽  
The Time Domain

The conjugate gradient method (CGM) is compared with the time domain method (TDM) in the paper. The numerical simulation results show that the CGM have higher identification accuracy and robust noise immunity as well as producing an acceptable solution to ill-posed problems to some extent when they are used to identify the moving force. When the bending moment responses are used to identify the time-varying loads, the identification accuracy is more obviously improved than the TDM, which is more suitable for the time-varying loads identification.

scholarly journals Experimental and simulated milling stability tests

Mechanik ◽  
2017 ◽  
Vol 90 (11) ◽  
pp. 965-967
Author(s):  
Piotr Andrzej Bąk ◽  
Krzysztof Jemielniak
Keyword(s):  
Numerical Simulation ◽  
Stability Analysis ◽  
Time Domain ◽  
Cutting Parameters ◽  
Milling Machine ◽  
Machined Surface ◽  
Simulation Results ◽  
The Stability ◽  
The Time Domain

Self-excited vibrations significantly reduce the milling productivity, deteriorate the quality of machined surface and tool life. One of the ways to avoid these vibrations is to modify the cutting parameters based on the stability analysis results. A method of numerical simulation of self-excited vibrations in the time domain can be used for this purpose. A comparison of numerical simulation results with those from experiments conducted using a milling machine is presented. The results confirm the correctness of applied modeling.

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