Dynamic similarity analysis for a piezo-electromechanical system

2020 ◽  
Vol 64 (1-4) ◽  
pp. 103-110
Author(s):  
Shuo Hou ◽  
Xing Tan ◽  
Jincheng He ◽  
Xi Deng ◽  
Chen Xi ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Scaling Laws ◽  
Proof Mass ◽  
Electromechanical System ◽  
Similarity Analysis ◽  
Dynamic Similarity ◽  
Prototype Structure ◽  
Similarity Problem ◽  
Piezoelectric Stacks ◽  
Similitude Theory

Most research about using piezoelectric stacks to suppress vibration of mechanical structures didn’t involve the similarity problem for the piezoelectric stacks. The goal of this paper is to investigate the dynamic similarity between a prototype piezo stack and a scaled up or down piezo stack, whilst discussing the feasibility of predicting the vibration of prototype structure which use the piezoelectric stacks for vibration control. To illustrate this problem concisely, a single-DOF system consists of a proof mass and a piezo stack shunted with a series RL circuit is considered. Firstly, the governing equation of such piezo-electromechanical system in frequency domain is derived. Next the dynamic similarity of prototype and model stack is analyzed by similitude theory. After that the scaling laws are derived. Finally, a numerical simulation and relative error analysis are given to demonstrate the scaling laws.

Structural similitudes of stiffened cylinders

2017 ◽  
Vol 24 (3) ◽  
pp. 527-541 ◽  
Author(s):  
G Petrone ◽  
M Manfredonia ◽  
S De Rosa ◽  
F Franco
Keyword(s):  
Numerical Simulation ◽  
Structural Engineering ◽  
Scaling Laws ◽  
Similarity Theory ◽  
Design Tool ◽  
Engineering Science ◽  
The Finite Element Method ◽  
Engineering Problems ◽  
Incomplete Similarity ◽  
Scaled Models

Similarity theory is a branch of engineering science that deals with establishing conditions of similarity among phenomena and is applied to various fields, such as structural engineering problems, vibration and impact. Tests and numerical simulation of scaled models are still a valuable design tool, whose purpose is to accurately predict the behaviour of large or small prototypes through scaling laws applied to the experimental and numerical results. The aim of this paper is to predict the behaviour of the complete and incomplete similarity of stiffened cylinders by applying distorted scaling laws of the models in similitude. The investigation is performed using models based on the finite element method within commercial software. Two classes of cylinders scaled, with different laws, and, hence, reproducing replicas (exact similitude) and avatars (distorted similitude) are investigated.

scholarly journals A Review of Similitude Methods for Structural Engineering

2019 ◽  
Vol 71 (3) ◽  
Author(s):  
Alessandro Casaburo ◽  
Giuseppe Petrone ◽  
Francesco Franco ◽  
Sergio De Rosa
Keyword(s):  
Size Effects ◽  
Structural Engineering ◽  
Necessary Conditions ◽  
Rate Sensitivity ◽  
Full Scale ◽  
Test Article ◽  
Depth Analysis ◽  
Prototype Structure ◽  
Similitude Theory ◽  
Full Scale Testing

Similitude theory allows engineers, through a set of tools known as similitude methods, to establish the necessary conditions to design a scaled (up or down) model of a full-scale prototype structure. In recent years, to overcome the obstacles associated with full-scale testing, such as cost and setup, research on similitude methods has grown and their application has expanded into many branches of engineering. The aim of this paper is to provide as comprehensive a review as possible about similitude methods applied to structural engineering and their limitations due to size effects, rate sensitivity phenomena, etc. After a brief historical introduction and a more in-depth analysis of the main methods, the paper focuses on similitude applications classified, first, by test article, then by engineering fields.

Reconsideration of the Fan Scaling Laws: Part I — Theory

2003 ◽  
Author(s):  
Asad M. Sardar ◽  
William K. George
Keyword(s):  
Scaling Laws ◽  
Stokes Equations ◽  
Performance Testing ◽  
Navier Stokes ◽  
Speed Ratio ◽  
Navier Stokes Equations ◽  
Fan Performance ◽  
Dynamic Similarity ◽  
Scaling Parameters ◽  
Fan Speed

Generalized Fan Scaling Laws (GSFL) are derived for the scaling of fan performance. These follow from first principles using the Navier-Stokes equations appropriate to rotating and swirling flows. Not surprisingly, both Strouhal and Reynolds number similarity must be maintained. Thus for a geometrically similar family of fans, dynamic similarity is only possible if ΩD/U = constandUD/ν = const. If the second relation is solved for U and substituted into the first, it follows that full dynamic similarity is possible only if ΩD2/ν = const. This can be contrasted with the classical fan laws (CFSL) which for the same flow rate coefficient would imply that Q/ΩD3 (or U/ΩD) = const, implying that both fan size ratio and fan speed ratio are independent fan scaling parameters. Clearly for dynamic similarity to be maintained, the velocity and fan speed can not be varied independently (i.e. fan size and fan speed are not independent scaling parameters), contrary to the implications of the classical fan scaling laws. Further implications of the differences between the classical and generalized scaling laws for fan performance testing and design will be explored. Also several examples will be given in Part II as to how the generalized scaling laws can be applied in design practice.

Scaling Effect on Dynamic Impact Response of Structures in Fluid Fields

2013 ◽  
Author(s):  
Zhongheng Guo ◽  
Lingyu Sun ◽  
Taikun Wang ◽  
Junmin Du ◽  
Han Li ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Dimensional Analysis ◽  
Large Scale ◽  
Scaling Laws ◽  
Scaling Law ◽  
Fluid Pressure ◽  
Structural Safety ◽  
Scale Model ◽  
Small Scale ◽  
Water Tank

At the conceptual design phase of a large-scale underwater structure, a small-scale model in a water tank is often used for the experimental verification of kinematic principles and structural safety. However, a general scaling law for structure-fluid interaction (FSI) problems has not been established. In the present paper, the scaling laws for three typical FSI problems under the water, rigid body moves at a given kinematic equation or is driven by time-dependent fluids with given initial condition, as well as elastic-plastic body moves and then deforms subject to underwater impact loads, are investigated, respectively. First, the power laws for these three types of FSI problems were derived by dimensional analysis method. Then, the laws for the first two types were verified by numerical simulation. In addition, a multipurpose small-scale water sink test device was developed for numerical model updating. For the third type of problem, the dimensional analysis is no longer suitable due to its limitation on identifying the fluid pressure and structural stress, a simulation-based procedure for dynamics evaluation of large-scale structure was provided. The results show that, for some complex FSI problems, if small-scale prototype is tested safely, it doesn’t mean the full-scale product is also safe if both their pressure and stress are the main concerns, it needs further demonstration, at least by numerical simulation.

Dynamics of an Electromechanical System With Angular and Ferroresonant Nonlinearities

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
D. O. Tcheutchoua Fossi ◽  
P. Woafo
Keyword(s):  
Numerical Simulation ◽  
Lyapunov Exponent ◽  
Harmonic Balance ◽  
Chaotic Behavior ◽  
Harmonic Balance Method ◽  
Electromechanical System ◽  
Bifurcation Diagrams ◽  
Oscillatory Solutions ◽  
Torsion Bar ◽  
Hysteresis Phenomena

The purpose of this paper is to study the dynamics of an electromechanical system consisting of a torsion-bar or two mechanical pumps activated by an electromotor. Oscillatory solutions showing the jump and hysteresis phenomena are obtained using the harmonic balance method and direct numerical simulation. Chaotic behavior is presented via the bifurcation diagrams and corresponding Lyapunov exponent. Some implications of the results on the applications of the devices are discussed.

Mass Transport and Shear Stress in a Microchannel Bioreactor: Numerical Simulation and Dynamic Similarity

2005 ◽  
Vol 128 (2) ◽  
pp. 185-193 ◽  
Author(s):  
Yan Zeng ◽  
Thong-See Lee ◽  
Peng Yu ◽  
Partha Roy ◽  
Hong-Tong Low
Keyword(s):  
Numerical Simulation ◽  
Shear Stress ◽  
Mass Transport ◽  
Flow Model ◽  
Three Dimensional ◽  
Shear Stresses ◽  
Dynamic Similarity ◽  
Simplified Analysis ◽  
Combined Parameters ◽  
Substrate Concentrations

Microchannel bioreactors have been used in many studies to manipulate and investigate the fluid microenvironment around cells. In this study, substrate concentrations and shear stresses at the base were computed from a three-dimensional numerical flow-model incorporating mass transport. Combined dimensionless parameters were developed from a simplified analysis. The numerical results of substrate concentration were well correlated by the combined parameters. The generalized results may find applications in design analysis of microchannel bioreactors. The mass transport and shear stress were related in a generalized result. Based on the generalized results and the condition of dynamic similarity, various means to isolate their respective effects on cells were considered.

Dynamic Similarity Scaling Laws Applied to Cables

1972 ◽  
Vol 6 (2) ◽  
pp. 111-114 ◽  
Author(s):  
M. LOWELL COLLIER
Keyword(s):  
Scaling Laws ◽  
Dynamic Similarity ◽  
Similarity Scaling
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