Dynamic Behavior of Complex Fluid-Filled Tubing Systems—Part 1: Tubing Analysis

1998 ◽  
Vol 123 (1) ◽  
pp. 71-77 ◽  
Author(s):  
Forbes T. Brown ◽  
Stephen C. Tentarelli
Keyword(s):  
Frequency Response ◽  
Dynamic Behavior ◽  
Transmission Matrix ◽  
Matrix Approach ◽  
Frequency Dependent ◽  
Long Wavelength ◽  
System Models ◽  
Analogous System ◽  
Complex Fluid ◽  
Poisson Coupling

A general transmission-matrix approach is given for finding the frequency response of linearized long-wavelength models for the vibration in systems with straight and curved fluid-filled tubes. Couplings between the fluid and wall motions include the Bourdon effect, frequency-dependent wall shear, the Poisson coupling and the effect of discontinuities. The introduction of a global transmission matrix allows nonplanar tubing systems of virtually any complexity to be analyzed, overcoming the round-off error problem that plagues the basic transmission-matrix approach for this and analogous system models. Corroborating experiments focus on the Poisson and Bourdon effects.

The Frequency Response of Electrochemical Wall Shear Probes in Pulsatile Flow

1987 ◽  
Vol 109 (1) ◽  
pp. 60-64 ◽  
Author(s):  
L. Talbot ◽  
J. J. Steinert
Keyword(s):  
Mass Transfer ◽  
Frequency Response ◽  
Pulsatile Flow ◽  
Straight Tube ◽  
Asymptotic Results ◽  
Frequency Dependent ◽  
Shear Rates ◽  
Pulsatile Flows ◽  
Wall Shear ◽  
Good Agreement

The frequency response of surface-mounted electrochemical mass transfer probes used to deduce wall shear rates has been investigated experimentally for the case of fully developed laminar pulsatile flow in a straight tube. Generally good agreement is found with the asymptotic results obtained by Lighthill’s methods. The significance of the results with regard to the investigation of models of pulsatile flows of physiological interest is discussed. It is concluded that the frequency-dependent phase and amplitude corrections required to obtain accurate wall shear measurements are of such magnitudes as to render impractical the use of electrochemical probes to determine wall shear rates in these flows.

A simple design of SIW horn fed multibeam transmitarray antenna using transmission matrix approach

2019 ◽  
Vol 62 (1) ◽  
pp. 411-417
Author(s):  
Baokun Xi ◽  
Yang Cai ◽  
Qianzhong Xue ◽  
Yong Wang ◽  
Shaopeng Yang ◽  
...  
Keyword(s):  
Transmission Matrix ◽  
Simple Design ◽  
Matrix Approach

Frequency Response of a Viscoelastic Tensegrity Model: Structural Rearrangement Contribution to Cell Dynamics

2005 ◽  
Vol 128 (4) ◽  
pp. 487-495 ◽  
Author(s):  
Patrick Cañadas ◽  
Sylvie Wendling-Mansuy ◽  
Daniel Isabey
Keyword(s):  
Frequency Response ◽  
Essential Feature ◽  
Structural Rearrangement ◽  
Contact Dynamics ◽  
Specific Power ◽  
Viscous Effects ◽  
Cell Dynamics ◽  
Frequency Dependent ◽  
Tensegrity Structure

In an attempt to understand the role of structural rearrangement onto the cell response during imposed cyclic stresses, we simulated numerically the frequency-dependent behavior of a viscoelastic tensegrity structure (VTS model) made of 24 elastic cables and 6 rigid bars. The VTS computational model was based on the nonsmooth contact dynamics (NSCD) method in which the constitutive elements of the tensegrity structure are considered as a set of material points that mutually interact. Low amplitude oscillatory loading conditions were applied and the frequency response of the overall structure was studied in terms of frequency dependence of mechanical properties. The latter were normalized by the homogeneous properties of constitutive elements in order to capture the essential feature of spatial rearrangement. The results reveal a specific frequency-dependent contribution of elastic and viscous effects which is responsible for significant changes in the VTS model dynamical properties. The mechanism behind is related to the variable contribution of spatial rearrangement of VTS elements which is decreased from low to high frequency as dominant effects are transferred from mainly elastic to mainly viscous. More precisely, the elasticity modulus increases with frequency while the viscosity modulus decreases, each evolution corresponding to a specific power-law dependency. The satisfactorily agreement found between present numerical results and the literature data issued from in vitro cell experiments suggests that the frequency-dependent mechanism of spatial rearrangement presently described could play a significant and predictable role during oscillatory cell dynamics.

The Generalized Response of Servovalve-Controlled, Single-Rod, Linear Actuators and the Influence of Transmission Line Dynamics

1984 ◽  
Vol 106 (2) ◽  
pp. 157-162 ◽  
Author(s):  
J. Watton
Keyword(s):  
Transmission Line ◽  
Frequency Response ◽  
System Design ◽  
Dynamic Behavior ◽  
Transmission Lines ◽  
Fatigue Testing ◽  
Open Loop ◽  
Linear Actuators ◽  
Probable Type

The open-loop response of servovalve-controlled single-rod linear actuators in investigated for both the extending and retracting cases. A linearized frequency response technique is used to establish the probable type of dynamic behavior. Nondimensional results are presented as an aid to system design, and a boundary is established such that a simplified approximation may be used. A particular class of system is then examined where interconnecting transmission lines would be important, and the techniques previously used are modified accordingly. The techniques are verified with a precision actuator developed for fatigue testing of vehicle and airframe systems.

Joint Parameters Identification of a Structure With Large Number of Discrete Joints

2003 ◽  
Author(s):  
J. H. Wang ◽  
S. C. Chuang
Keyword(s):  
Frequency Response ◽  
Dynamic Behavior ◽  
Error Function ◽  
Parameters Identification ◽  
New Method ◽  
Response Functions ◽  
Traditional Methods ◽  
Measured Frequency Response ◽  
Joint Parameters ◽  
Better Than

The joint parameters of a structure with a large number of discrete joints generally are very difficult to identify accurately. The difficulty is due to the fact that the dynamic behavior of a structure becomes more complex with more number of joints. A new identification method which uses the measured frequency response functions (FRFs) to identify the joint parameters is proposed in this work to overcome this difficulty. The new method uses an error function to select different best data to identify different joints so that the accuracy of the identification can be improved. The accuracy of the new method and other two traditional methods is compared in this work. The results show that the accuracy of the proposed new method is far better than other two previous methods. The proposed new method has special advantage when (1) the number of joints is large, (2) the orders of magnitude of the joint parameters are different significantly.

Calculating Impulse and Frequency Response of Large Power System Models for Realization Identification

2020 ◽  
Vol 35 (5) ◽  
pp. 3825-3834
Author(s):  
Dmitry Rimorov ◽  
C. M. Rergis ◽  
Innocent Kamwa ◽  
Ali Moeini ◽  
Jinan Huang ◽  
...  
Keyword(s):  
Power System ◽  
Frequency Response ◽  
Large Power ◽  
System Models

Coupling Sound Absorbing Materials With an Air Cavity Using Frequency Dependent Bulk Material Properties

2016 ◽  
Author(s):  
Shung H. Sung ◽  
Donald J. Nefske
Keyword(s):  
Finite Element ◽  
Frequency Response ◽  
Material Properties ◽  
Complex Frequency ◽  
Air Cavity ◽  
Frequency Dependent ◽  
Absorbing Materials ◽  
Mode Method ◽  
Modal Solution ◽  
Solution Methodology

This paper presents the acoustic finite element method and the modal solution method for coupling sound absorbing materials with an air cavity to predict the sound pressure frequency response. The sound absorbing materials are represented with complex, frequency-dependent, effective mass-density and bulk-modulus properties obtained from the acoustic impedance of material samples. To couple the sound absorber cavity and air cavity, the boundary conditions at the interface between the cavities requires equality of pressure and equality of acoustic volume flow. Two modal solution methods are developed to compute the frequency response of the coupled system with frequency dependent material properties: the component mode method and the coupled mode method. The finite element and modal solution methodology is developed in a form readily adaptable for implementation in commercially available codes. The accuracy of the modal solution methodology is assessed for modeling a one-dimensional air tube terminated with absorbent material and the seats in an automobile passenger compartment.

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