Prediction of insertion loss of lagging in rectangular duct using statistical energy analysis

2019 ◽  
Vol 67 (6) ◽  
pp. 438-446
Author(s):  
M. Yoganandh ◽  
Jade Nagaraja ◽  
B. Venkatesham
Keyword(s):  
Insertion Loss ◽  
Power Flow ◽  
Energy Analysis ◽  
Transmission Loss ◽  
Flow Analysis ◽  
Computational Cost ◽  
Statistical Energy Analysis ◽  
Rectangular Duct ◽  
Modal Density ◽  
Element Method

In this article, statistical energy analysis (SEA) is used to predict insertion loss from a lagged rectangular HVAC duct. For a lagged duct, all duct walls are treated from outside with acoustic material. Although deterministic methods like the finite element method (FEM), boundary element method (BEM), and wave based methods can predict the breakout noise, these methods have limitations in handling systems with high modal density due to higher computational cost. In this study, a rectangular duct is divided into six subsystems, which are four duct walls (each wall considered as a subsystem), internal air cavity and external airspace. Power flow analysis is performed on all subsystems to calculate transverse transmission loss of an unlined duct and insertion loss for a lagged duct. Predicted transverse transmission loss values are validated with ASHRAE data and Insertion loss values with literature. The results obtained are in good agreement.

Power Flow and Energy Sharing between an Oscillator and a Continuous Receiver Structure

2011 ◽  
Vol 189-193 ◽  
pp. 1914-1917
Author(s):  
Lin Ji
Keyword(s):  
High Frequency ◽  
Power Flow ◽  
Energy Analysis ◽  
Statistical Energy Analysis ◽  
Coupled Subsystems ◽  
Modal Density ◽  
Vibration Problems ◽  
Energy Sharing ◽  
High Modal Density ◽  
Vibration Modeling

A key assumption of conventional Statistical Energy Analysis (SEA) theory is that, for two coupled subsystems, the transmitted power from one to another is proportional to the energy differences between the mode pairs of the two subsystems. Previous research has shown that such an assumption remains valid if each individual subsystem is of high modal density. This thus limits the successful applications of SEA theory mostly to the regime of high frequency vibration modeling. This paper argues that, under certain coupling conditions, conventional SEA can be extended to solve the mid-frequency vibration problems where systems may consist of both mode-dense and mode-spare subsystems, e.g. ribbed-plates.

Statistical Energy Analysis of Wind Noise in High-Speed Train Cab

2012 ◽  
Vol 249-250 ◽  
pp. 307-313 ◽  
Author(s):  
Xiao Yan Yang ◽  
You Gang Xiao ◽  
Yu Shi
Keyword(s):  
High Speed ◽  
Power Flow ◽  
Energy Analysis ◽  
Simulation Method ◽  
Statistical Energy Analysis ◽  
High Speed Train ◽  
Wind Noise ◽  
Modal Density ◽  
Head Surface ◽  
Loss Factors

Statistical energy analysis(SEA) method has many advantages in analysis of high frequency, high modal density and complex dynamic systems. Dividing high-speed train cab into a series of sub-systems, the SEA model of high-speed train cab was established. The factors affecting the cab noise, such as modal density, damping loss factors, coupling loss factors, were gotten by theoretical analysis combined with experiments. Using large eddy simulation method, the fluctuation pressures from train head surface were calculated. Using fluctuation pressure as excitation source, wind noise spectra and power flow of sub-systems in cab were obtained, which provided the basis for the control of high-speed train cab noise.

Sound and Vibration Transmission Through Panels and Tie Beams Using Statistical Energy Analysis

1971 ◽  
Vol 93 (3) ◽  
pp. 775-781 ◽  
Author(s):  
M. J. Crocker ◽  
M. C. Battacharya ◽  
A. J. Price
Keyword(s):  
Energy Analysis ◽  
Transmission Loss ◽  
Sound Transmission ◽  
Accurate Method ◽  
Acoustic Energy ◽  
Statistical Energy Analysis ◽  
Sound Transmission Loss ◽  
Lateral Shear ◽  
Architectural Acoustics ◽  
Bending Waves

The transmission of sound and vibration through structures is of interest in many noise control problems, including architectural acoustics, sound transmission through aircraft, spacecraft and ships, and the transmission of noise through machinery and engine enclosures. Statistical energy analysis provides a simple and accurate method of approaching these problems. In this paper, theory is examined for the transmission of acoustic energy through single panels, independent double panels, and double panels connected with tie beams. In the single panel case, the theoretical model consists of three linearly coupled oscillators; room-panel-room. The independent double panel case consists of five oscillators; room-panel-cavity-panel-room. In the connected double panel case, the tie beams must be accounted for as the sixth oscillator. A coupling loss factor is determined for the ties by considering the transmission of longitudinal waves, bending waves, and lateral shear waves in the ties. Both resonant and nonresonant transmission are included in the theory. It is shown that for a single panel, the experimental sound transmission loss, panel radiation resistance, and vibration amplitude are all well predicted by the theory. The experimental sound transmission loss is also well predicted in the independent double panel and coupled double panel cases.

Automotive Floor Sound Package Design Using Statistical Energy Analysis

2014 ◽  
Vol 670-671 ◽  
pp. 1102-1105
Author(s):  
Ju Yue Ding ◽  
Jian Wang Shao
Keyword(s):  
Automotive Industry ◽  
Energy Analysis ◽  
Transmission Loss ◽  
Statistical Energy Analysis ◽  
Vehicle Interior ◽  
Vehicle Noise ◽  
Package Design ◽  
Increasing Demand ◽  
Floor System ◽  
Insulation Performance

An increasing demand for vehicle noise control has been proposed and at the same time, vehicle weight and fuel economy have become critical for the automotive industry. The methodology of statistical energy analysis (SEA) is used to balance both light weight and high noise insulation performance. In this paper, the floor system which is one of the major paths for vehicle interior noise is studied with two sound package systems, the original floor insulation system and the lightweight one. The vehicle floor system is modeled by SEA and its transmission loss (TL) is analyzed. The results show that under certain sound package coverage, the TL of the floor system with the lightweight sound package is a little larger than the TL with the lightweight one. However, the lightweight sound package system has better absorption property and the advantage of weight reduction. Finally, in order to get the better TL, the sound package design is performed.

Power Flow Finite Element Analysis of Dynamic Systems: Basic Theory and Application to Beams

1989 ◽  
Vol 111 (1) ◽  
pp. 94-100 ◽  
Author(s):  
D. J. Nefske ◽  
S. H. Sung
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Dynamic Systems ◽  
Power Flow ◽  
Control Volume ◽  
Flow Analysis ◽  
Vibration Response ◽  
Element Analysis ◽  
Power Flow Analysis ◽  
Element Method

A power flow analysis has been developed for predicting the vibration response of dynamic systems to high frequencies at which the traditional finite element method is no longer practical. As compared to Statistical Energy Analysis, which predicts an overall vibration response of each dynamic subsystem, the power flow analysis enables one to predict the spatial variation of the vibration response within each subsystem, as well as the power flow and vibration response throughout the entire system. The formulation of the power flow analysis is based on a differential, control-volume approach and is shown to result in a partial differential equation of the heat conduction type which can be solved by applying the finite element method. Example applications to (1) an uncoupled beam and (2) two coupled beams are presented to illustrate the analysis.

Mechanical Power Flow Between Stiffened Plates and Viscoelastic Discrete Systems

1986 ◽  
Vol 108 (2) ◽  
pp. 155-164 ◽  
Author(s):  
E. Goldfracht ◽  
G. Rosenhouse
Keyword(s):  
Power Flow ◽  
Energy Analysis ◽  
Power Transmission ◽  
Discrete Systems ◽  
Vibration Energy ◽  
Stiffened Plates ◽  
Statistical Energy Analysis ◽  
Frequency Range ◽  
Lower Frequency Range ◽  
Fundamental Theorems

In this paper we primarily discuss a theory of power transmission and vibration energy distribution of dynamically loaded structures. The loads are random and the system comprises linked elements, which consist of machine-supported stiffened plates. Fundamentally, the theory is deterministic, but in addition it uses some features of the SEA. In fact, the analysis is intended to verify fundamental theorems of the Statistical Energy Analysis in the lower frequency range.

Research on Evaluation of Vibration Isolation Efficiency Based on Power Flow Analysis

2014 ◽  
Vol 590 ◽  
pp. 149-154 ◽  
Author(s):  
Xue Tao Weng ◽  
Rui Huo ◽  
Shu Ying Li ◽  
Cui Ping Liu
Keyword(s):  
Insertion Loss ◽  
Power Flow ◽  
Vibration Isolation ◽  
Flow Analysis ◽  
Vibration Level ◽  
Transmitted Power ◽  
Research On Evaluation ◽  
Power Flow Analysis ◽  
Level Difference ◽  
Set Up

Problems of estimation of vibration isolation effectiveness are discussed based on vibratory power flow analysis, and a new insertion loss character — power flow insertion loss is proposed for evaluation of isolation efficiency. Spectra characteristics of the power flow insertion loss and their relationship with transmitted power flow and vibration level difference are investigated through numerical simulation. And in consideration of the inconvenience of practical testing of insertion loss and power flow, an attempt is made to set up numerical correspondence between power flow insertion loss and the current widely applied vibration level difference measurement, through theoretical analysis and experiments.

Sign in / Sign up

Export Citation Format

Share Document