An Investigation of the Effect of Weatherstrip Seals on Vehicle Vibration and Acoustics Using an Alternative Modeling Technique

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Aydin Tuncer ◽  
Gunay Anlas ◽  
Yasin Yilmaz
Keyword(s):  
Finite Element ◽  
Sound Pressure ◽  
Element Model ◽  
Pressure Level ◽  
Test Structure ◽  
Vibration Modes ◽  
Passenger Compartment ◽  
Response Curves ◽  
Frequency Shifts ◽  
Full Vehicle

In this study, the effect of weatherstrip seals on panel vibrations and structure borne noise is studied. First, a test structure is built to model vehicle's body and door; hammer impact tests are carried out to determine frequency shifts in door vibration modes with the inclusion of rubber seals. Then, a finite element model of the test structure is built. Rubber seals are modeled as spring elements, and a modal analysis is carried out. Finite element results are compared to experimental ones to check the validity of the model used. Following a parametric study to determine stiffness of linear springs, the full vehicle is modeled using finite elements, and the effect of rubber weatherstrip seals on sound pressure level (SPL) inside the passenger compartment is studied. Frequency response curves are plotted.

Validation of an Acoustic Finite Element Model of an Automobile Passenger Compartment

2009 ◽  
Author(s):  
Sangyun Lee ◽  
Kwangseo Park ◽  
Shung H. Sung ◽  
Donald J. Nefske
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Sound Pressure ◽  
Element Model ◽  
Rear Seat ◽  
Pressure Response ◽  
Mode Shapes ◽  
Instrument Panel ◽  
Passenger Compartment ◽  
Vehicle Interior

An acoustic finite-element model of an automobile passenger compartment that represents the more complicated vehicle interior acoustic characteristics is developed and experimentally assessed using loudspeaker excitation. The acoustic finite-element model represents the passenger compartment cavity, trunk compartment cavity, front and rear seats, parcel shelf, door volumes, and IP (Instrument Panel) volume. The model accounts for the coupling between the compartment cavity and trunk cavity through the rear seat and parcel shelf, and the coupling between the compartment cavity and the door and IP panel volumes. Modal analysis tests of a vehicle were conducted using loudspeaker excitation to identify the compartment cavity modes and sound pressure response at a large number of interior locations. Comparisons of the predicted versus measured mode frequencies, mode shapes, and sound pressure response at the occupant ear locations are made to assess the accuracy of the model to 400 Hz.

Correlation of an Acoustic Finite Element Model of the Automobile Passenger Compartment Using Loudspeaker Excitation

2007 ◽  
Author(s):  
Shung H. Sung ◽  
Donald J. Nefske ◽  
Douglas A. Feldmaier
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Sound Pressure ◽  
Element Model ◽  
Pressure Response ◽  
Acoustic Properties ◽  
Passenger Compartment ◽  
Model Comparisons

An acoustic finite-element model of the automobile passenger compartment is developed and experimentally assessed for predicting the sound pressure response in the compartment. The acoustic finite-element model represents both the passenger compartment cavity and the trunk compartment cavity, with the coupling between them through the rear seats for which the acoustic properties are determined from a modified “heavy air” approximation. Measurements of the sound pressure response in the passenger compartment are obtained using a specially developed loudspeaker excitation device for assessing the accuracy of the model. Comparisons are made of the predicted versus measured sound pressure response to 300 Hz for loudspeaker excitation in both the passenger and trunk compartments.

The use of façade sun shading systems for the reduction of indoor and outdoor sound pressure levels

2019 ◽  
Vol 26 (3) ◽  
pp. 181-206 ◽  
Author(s):  
Patrizio Fausti ◽  
Simone Secchi ◽  
Nicolò Zuccherini Martello
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Element Model ◽  
Pressure Level ◽  
Building Facade ◽  
Absorbing Material ◽  
Shading Devices ◽  
Shading Device

External shading devices are widely used in recent buildings because they reduce the greenhouse effect due to the solar irradiation through transparent surfaces and the glare effects in interiors. The acoustic effects of these devices have not been well investigated in the literature. In this article, we use a bi-dimensional pressure acoustics finite element model of a shading device attached to a building façade, in frequency domain, to analyse the effects both in the indoor and in the outdoor environments. The finite element model was validated with experimental measurements carried out in a semi-anechoic chamber and then extended to an urban scale to evaluate the effect in the reduction of outdoor noise due to traffic. To improve the acoustic effect of the shading device, a sound absorbing material was added to the bottom side of each louvre. Results of the simulations show that external shading devices tend to increase the sound pressure level over the building façade, while the introduction of the sound absorbing material behind each louvre reduces this problem. The dependencies of the sound pressure level reduction to the geometrical factors of the shading device were investigated by means of the finite element model. The installation of louvres on a building façade can affect also the sound pressure level over a façade of a building placed 20 m away, across a road. In this article, both the effect over the façade of the opposite building and the effect over the urban area between the two buildings are analysed.

Dynamic Characteristics of a Long-Span Cable-Stayed Bridge

2011 ◽  
Vol 480-481 ◽  
pp. 1496-1501
Author(s):  
Liu Hui
Keyword(s):  
Finite Element ◽  
Dynamic Characteristics ◽  
Iteration Method ◽  
Natural Frequencies ◽  
Element Model ◽  
Vibration Modes ◽  
Cable Stayed Bridge ◽  
Long Span ◽  
Subspace Iteration ◽  
Floating System

In order to study the dynamic characteristics of a super-long-span cable-stayed bridge which is semi-floating system, the spatial finite element model of this cable-stayed bridge was established in ANSYS based on the finite element theory.Modal solution was conducted using subspace iteration method, and natural frequencies and vibration modes were obtained.The dynamic characteristics of this super-long-span cable-stayed bridge were then analyzed.Results showed that the super-long-span cable-stayed bridge of semi-floating system has long basic cycle, low natural frequencies, dense modes and intercoupling vibration modes.

scholarly journals Fuzzy finite element model updating of the DLR AIRMOD test structure

2017 ◽  
Vol 52 ◽  
pp. 512-526 ◽  
Author(s):  
H. Haddad Khodaparast ◽  
Y. Govers ◽  
I. Dayyani ◽  
S. Adhikari ◽  
M. Link ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Model Updating ◽  
Element Model ◽  
Test Structure ◽  
Finite Element Model Updating ◽  
Fuzzy Finite Element

Vibration Response of a Thin-Walled Cylindrical Pipe with Liquid

2012 ◽  
Vol 189 ◽  
pp. 345-349
Author(s):  
Yu Lan Wei ◽  
Bing Li ◽  
Li Gao ◽  
Ying Jun Dai
Keyword(s):  
Finite Element ◽  
Natural Frequencies ◽  
Element Model ◽  
Beam Model ◽  
Vibration Modes ◽  
Timoshenko Beam Model ◽  
Cylindrical Pipe ◽  
Bending Vibration ◽  
Beam Bending ◽  
Thin Walled

Vibration characteristics of the thin-walled cylindrical pipe are affected by the liquid within the pipe. The natural frequencies and vibration modes of the pipe without liquid are analyzed by the theory of beam bending vibration and finite element model, which is based on the Timoshenko beam model. The first three natural frequencies and vibration modes of the pipe with or without liquid are acquired by experiments. As shown in the experiment results, the natural frequencies of the containing liquid pipe are lower than the natural frequencies of the pipe without liquid.

Self-Vibration Characteristics of Plane Gate in Inverted Siphon Project

2012 ◽  
Vol 160 ◽  
pp. 64-68
Author(s):  
Hui Fang Xue ◽  
You Wang
Keyword(s):  
Finite Element ◽  
Large Scale ◽  
Element Model ◽  
Vibration Characteristics ◽  
The Self ◽  
Vibration Modes ◽  
Vibration Frequencies ◽  
Small Opening ◽  
First Order ◽  
Inverted Siphon

Based on the vibration problem of the plane gate in the inverted siphon exit of a large-scale hydraulic project in northern Xinjiang, the software ANSYS is used to build the entity model and finite element model. Considering the influence of fluid-solid coupling, the self-vibration characteristics of the gate in the water and without water are analyzed. The first six self-vibration frequencies and vibration modes of the gate are calculated. The results show that the height of water has a significant impact on the self-vibration frequencies of the plane gate. The first order natural frequency on the condition of small opening is decreased by 28.5%. It shows that the structure of the plane gate must be improved.

Thickness-resonance waves in underlays of floating screed

2021 ◽  
Vol 263 (3) ◽  
pp. 2973-2983
Author(s):  
Charlotte Crispin ◽  
Debby Wuyts ◽  
Dijckmans Arne
Keyword(s):  
Finite Element ◽  
Transfer Matrix ◽  
Sound Pressure Level ◽  
Transfer Matrix Method ◽  
Matrix Method ◽  
Sound Pressure ◽  
Pressure Level ◽  
Experimental Results ◽  
Simplified Model ◽  
Negative Effects

The prediction of the reduction of impact sound pressure level ΔL according to annex C of the standard ISO 12354-2 gives an acceptable estimation of the floating floor's performance for thin resilient layers. However, the performance is often largely overestimated for thick resilient layers or for resilient layers combined with thermal layers. One reason for this is that the simplified model doesn't account for the thickness resonances in the underlays which can greatly affect ΔL. This is confirmed by comparing finite element and transfer matrix method simulations with experimental results. This paper establishes the mechanisms leading to the development of these resonance waves and provides some guidelines to estimate their negative effects on the ΔL.

Identification of cracks in an Euler–Bernoulli beam using Bayesian inference and closed-form solution of vibration modes

2020 ◽  
pp. 146442072096971
Author(s):  
Tianyu Wang ◽  
Mohammad Noori ◽  
Wael A. Altabey
Keyword(s):  
Finite Element ◽  
Bayesian Inference ◽  
Finite Element Model ◽  
Crack Detection ◽  
Closed Form Solution ◽  
Element Model ◽  
Form Solution ◽  
Vibration Modes ◽  
Vibration Data ◽  
The Finite Element Model

Over the past two decades, extensive research has been carried out in the field of structural health monitoring for damage detection in structural systems. Some crack detection methods are based on the finite element model of a beam and use vibration data are developed. These methods identify the crack by updating of the finite element model according to the vibration data of structure. This paper proposes a novel method for crack detection in Euler–Bernoulli beams based on the closed-form solution of mode shapes using Bayesian inference. The expression of vibration modes is derived analytically with the crack parameters as unknown variables. Subsequently, the Bayesian inference is used to obtain the probability density function of crack parameters and to evaluate the uncertainty of the modes. Finally, the method is applied to a series of numerical examples, including a beam with a single-crack and multi-cracks, to verify the effectiveness of this method.

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