Dynamic Similitude and Modeling

2018 ◽  
pp. 1403-1561
Author(s):  
Ahlam I. Shalaby
Keyword(s):  
Dynamic Similitude

Dynamic Similitude Technique for Predicting the Behaviour of Structures Subjected to Impact Loads

2022 ◽  
pp. 104160
Author(s):  
Tao Wang ◽  
Lei Ni ◽  
Tian Wu ◽  
Yuexin Wang ◽  
Xulong Xi ◽  
...  
Keyword(s):  
Impact Loads ◽  
Dynamic Similitude

scholarly journals Emergency Gate Vibration of the Pipe-Turbine Model

2000 ◽  
Vol 7 (1) ◽  
pp. 3-13 ◽  
Author(s):  
Andrej Predin ◽  
Roman Klasinc
Keyword(s):  
Data Transfer ◽  
Guide Vane ◽  
Natural Vibrations ◽  
Vibration Behavior ◽  
Kaplan Turbine ◽  
Gate Opening ◽  
Horizontal Shaft ◽  
Dynamic Similitude ◽  
The Moment ◽  
The Time Domain

The vibration behavior of an emergency gate situated on a horizontal-shaft Kaplan turbine is studied. The analysis and transfer of the dynamic movements of the gate are quite complex. In particular the behavior is examined of the emergency gate for the case when the power unit is disconnected from the system or there is a breakdown of the guide vane system at the moment when the maximal head and capacity are achieved. Experimental-numerical methods both in the time domain and in the frequency domain are employed. Natural vibrations characterize a first zone, corresponding to relatively small gate openings. As the gate opening increases, the vibration behavior of the gate becomes increasingly dependent on the swirl pulsations in the draft tube of the turbine. Finally, the data transfer from the model to the prototype by use of the dynamic similitude law is discussed.

Development of a Scaled Vehicle Model for Dynamics Testing

2021 ◽  
Author(s):  
R.R. Hewavithana ◽  
◽  
J.P.L. Ravihara ◽  
K.K.S. Wishwajith ◽  
U.L.S. Perera ◽  
...  
Keyword(s):  
Computer Simulations ◽  
Simulation Models ◽  
Autonomous Driving ◽  
Aggressive Driving ◽  
Scaled Model ◽  
State Behaviour ◽  
Dynamic Similitude ◽  
Scaled Models ◽  
Vehicle Testing ◽  
Future Work

The interest in using scaled models for dynamics testing of prototype vehicles is growing due to the high demand for autonomous driving. In the early design phases, vehicle testing is done using computer simulations. Even though computer simulations are proven to be extremely helpful in designing prototypes, simulation models need to be validated using realworld testing. There are high costs involved in vehicle testing and it’s dangerous to conduct aggressive driving manoeuvres with real drivers. As a solution, researchers have used scaled models. To validate the computer simulations, researchers matched the scaled model test data with full-size vehicle prototypes considering the dynamic similitude. However, previous work was limited to the analysis of the steady-state behaviour of vehicles. To accurately predict the behaviour, the transientstate response must be tested as well. Therefore, this paper outlines the precursory work of a scaled model with the ability to test both states during vehicle manoeuvres. This paper is structured as follows. Section II presents related work. Section III elaborates on the mathematical modelling and present the results of the computer simulations. Section IV presents the scaled model which will be developed. Section V concludes the findings, and present the future work of research.

Dynamic Similitude of Underground Structures

1964 ◽  
Vol 90 (3) ◽  
pp. 111-133
Author(s):  
Donald F. Young ◽  
Glenn Murphy
Keyword(s):  
Underground Structures ◽  
Dynamic Similitude

Wavemaker Limitations and Difficulties in Model Testing of Small High Speed Craft

2012 ◽  
Author(s):  
Thomas C. Fu ◽  
Anne M. Fullerton ◽  
Christine C. Schleicher
Keyword(s):  
Froude Number ◽  
High Speed ◽  
Dynamic Testing ◽  
Scale Effects ◽  
Model Testing ◽  
Viscous Effects ◽  
Sea State ◽  
Physical Size ◽  
Dynamic Similitude

Model testing of marine platforms has always focused on preserving geometric similitude and Froude number. While Froude scaling does provide a good approximation to true dynamic similitude, there are viscous effects which are not scaled. Additionally, the dynamic testing of small high speed marine craft presents difficulties due to their small size, so while one would prefer to minimize these effects by testing large models, model basin characteristics limit the physical size of the models that can be tested. These issues as they relate to model testing, including sea state scaling and scale effects, are discussed.

Effect of Load Frequency on Dynamic Similitude of Scaled Model

2013 ◽  
Vol 448-453 ◽  
pp. 3508-3513
Author(s):  
Yu Chao Song ◽  
Yan Nian Cai ◽  
Chao Ming Huang ◽  
Hong Liang Yu
Keyword(s):  
Finite Element Method ◽  
Scaled Model ◽  
Test Analysis ◽  
Modal Theory ◽  
Load Frequency ◽  
Model Dynamics ◽  
Prototype Structure ◽  
Key Factor ◽  
Dynamic Similitude ◽  
Model Structures

The similitude requirement of excited load was deduced to maintain the consistent vibration between scaled model and prototype structure, based on the modal theory of multi-DOFs systems. The similitude of load frequency was another demand to maintain the consistent vibration, with the similitude of structure size and load magnitude. The dynamic similitude problem of a liquid tank was studied by finite element method and test analysis respectively. The results show that the similitude of load frequency is the insurance for the consistency of prototype and scaled model structures vibration. In a case the magnitude error of displacement is 8% to 10%, and the displacement and acceleration have all changed distinctly without the similitude of load frequency. All the results indicate that the similitude of load frequency is the key factor to analyze the scaled model dynamics correctly.

A study of ultrasonic physical modeling of isotropic media based on dynamic similitude

Ultrasonics ◽  
2016 ◽  
Vol 70 ◽  
pp. 227-237 ◽  
Author(s):  
Leo K. Santos ◽  
J.J.S. de Figueiredo ◽  
Carolina B. da Silva
Keyword(s):  
Physical Modeling ◽  
Isotropic Media ◽  
Dynamic Similitude

Nonlinear Performance Simulation of RC Structures with Small-Scaled Model in Earthquake Simulation Test

2011 ◽  
Vol 243-249 ◽  
pp. 3717-3729
Author(s):  
Qing Li Meng ◽  
Min Zheng Zhang
Keyword(s):  
Numerical Simulation ◽  
Mechanical Behavior ◽  
Material Behavior ◽  
Small Scale ◽  
Earthquake Simulation ◽  
Simulation Test ◽  
Performance Simulation ◽  
Rc Structure ◽  
Dynamic Similitude ◽  
Nonlinear Performance

For small-scale RC structure model in earthquake simulation test, the material behavior of the model is hard to resemble the prototype well so that the model cannot simulate correctly the nonlinear performance of the prototype. On the basis of the dynamic similitude of mechanical behavior between common concrete and micro-concrete which derive from mechanical behavior tests, the simplified equivalent dynamic similitude relations, which are applicable to the nonlinear performance simulation with small-scale RC structure models in the earthquake simulation tests, have been proposed. By the numerical simulation of earthquake simulation tests and the deviation analysis, the dynamic simulation experimental method has been verified. In addition, for small-scaled RC model, to consider the similitude harmony between concrete and reinforcement used in the model, by adjusting the reinforcement and stirrup, or the effective section height (h0) and hoop spacing etc., simple element testing, shaking table test and numerical simulation were carried out to verify this model design method. Thus, it’s realizable that the small-scaled RC model can simulate correctly the nonlinear performance of the prototype.

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