scholarly journals Vibration Damping Measurement on Car Windshields

2018 ◽  
Vol 63 (1) ◽  
pp. 1-6
Author(s):  
Balázs Vehovszky ◽  
István Horváth ◽  
Karl Slenczka ◽  
Martin Schuster ◽  
Tamás Jakubík
Keyword(s):  
Loss Factor ◽  
Laser Scanning ◽  
Measuring Method ◽  
Vibration Damping ◽  
3D Laser Scanning ◽  
Damping Properties ◽  
Reverberation Time ◽  
Damping Loss Factor ◽  
Modal Behavior

Knowledge of the damping properties of a windshield is a fundamental element of the acoustical characterization of a car. The measuring method of damping for a windshield is presented in the paper. The damping loss factor – as a basic measure of mechanical damping – was determined experimentally by two means: the reverberation time from impact hammer testing as well as the modal behavior from 3D laser scanning vibrometer measurements. The results proved that the modal shapes have a fundamental effect on the measured damping values.

The Application of 3D Laser Scanning Method in the Measurement of Pressure Vessel

2017 ◽  
Vol 865 ◽  
pp. 595-598
Author(s):  
Hui Zeng Yin ◽  
Xin Wei Yang ◽  
Rui Lan Tian ◽  
Xiu Zhi Sui
Keyword(s):  
Pressure Vessel ◽  
Point Cloud ◽  
Laser Scanning ◽  
Convex Surface ◽  
Measuring Method ◽  
Point Cloud Data ◽  
3D Laser Scanning ◽  
Scanning Method ◽  
Cloud Data ◽  
Dangerous Goods

Pressure vessel is widely used in the industrial engineering. Many materials in pressure vessel are inflammable and explosive dangerous goods. If the accident happens, great harm will be done to the lives and properties of people. Some common methods for studying pressure vessel have obvious drawbacks. 3D laser scanning method uses non-contact measuring method and can directly obtain the point cloud data of the mass surface which can be used to reconstruct any convex surface. According to the advantages of 3D laser scanning method, in this paper, it is introduced to measure the dimensions of flanges in pressure vessel. The experimental results obtained have little errors, which certify that 3D laser scanning method can be used to measure the dimensions of flanges and further study the characteristics of pressure vessel.

Theoretical and Experimental Investigation of Vibration Damping Sheet Dynamic Behavior

2017 ◽  
Vol 265 ◽  
pp. 439-444
Author(s):  
V.D. Cherkasov ◽  
Yuriy V. Yurkin ◽  
V.V. Avdonin
Keyword(s):  
Experimental Investigation ◽  
Dynamic Behavior ◽  
Loss Factor ◽  
Experimental Studies ◽  
Structure Optimization ◽  
Theoretical Data ◽  
Vibration Damping ◽  
Damping Properties ◽  
Thin Slab ◽  
High Loss

A great deal of attention is presently being drawn to the question of noise and vibration damping. One of the basic means of the effective damping of unfavorable noises and vibrations is the usage of special sheets with high vibration and noise damping properties in thin-slab structures. In this article the results of a study of the dynamic behavior (of the loss factor) of multilayer vibration damping sheets are being described. The aim of this article is to show the design optimization of multilayer vibration damping sheets, carrying a high loss factor. The theoretical prerequisites for the structure optimization of vibration damping sheets, having a high loss factor, have been determined. The experimental studies on the influence of the thickness of the vibration damping layer, thickness and Young’s modulus of experimental with theoretical data have also been carried out. More effective designs of multilayer vibration damping sheets have been scientifically substantiated.

scholarly journals An analytical and experimental study on dampening material effects on the dynamic behavior of free-free aluminum sheets

2021 ◽  
pp. 111-122 ◽  
Author(s):  
R. Khorasani ◽  
S. A. Hosseini Kordkheili ◽  
H. Parviz
Keyword(s):  
Experimental Study ◽  
Analytical Solution ◽  
Dynamic Behavior ◽  
Loss Factor ◽  
Vibration Damping ◽  
Damping Properties ◽  
Free Boundary Conditions ◽  
Aluminum Sheets ◽  
Analytical Relations ◽  
Damping Systems

This work aims to present an experimentally verified analytical solution to examine damping properties of systems including viscoelastic treatments. Although there are several methods for characterizing the behavior of three-layer damping systems, the RKU method is the most frequently used one. In this paper, this method is modified such a way that to be applied for a five-layer damping system. The achieved analytical relations are then employed to study the effects of a four-layer vibration-absorbing coating on the dynamic behavior of an aluminum sheet with free-free boundary conditions. Since the vibration-damping properties of the coating are unknowns, its loss factor and shear modulus are experimentally extracted based on the ASTM E756-05 standard method. The comparison between the analytical solution and performed modal tests expresses the efficiency of the presented method.

NVH Performance of Lightweight Glazing Materials in Vehicle Design

2012 ◽  
Author(s):  
Yuksel Gur ◽  
Rick Wykoff ◽  
Kenneth E. Nietering ◽  
David A. Wagner
Keyword(s):  
Fuel Economy ◽  
Weight Reduction ◽  
Loss Factor ◽  
Lightweight Design ◽  
Research Work ◽  
Damping Properties ◽  
Tempered Glass ◽  
Weight Saving ◽  
Damping Loss Factor ◽  
Vehicle Purchase

Fuel economy and NVH (noise, vibration, and harshness) performance of vehicles are important parameters in a customer’s vehicle purchase decision. Lightweight vehicle designs are necessary to help with fuel economy improvements. In this research work, the weight saving potential and NVH performance of different lightweight glazing materials are investigated to help the lightweight design effort. The lightweight glazing materials included in this study are “Material A”, “Material B”, “Material C” with regular lamination, and “Material C” with acoustic lamination. The results of this research work indicate that the lightweight glazing materials have 30% to 40% weight saving potentials without NVH penalty. These materials have much higher damping properties than conventional tempered glass so they can compensate for the mass reduction influence on vehicle NVH. The tire patch noise reduction, vehicle transparency, and wind noise results of “Vehicle A” tested with different lightweight backlight designs indicate that there is almost no acoustic response difference between the tempered glass and other lightweight alternative backlight designs. Damping loss factor measurements indicate that “Material C” with acoustic PVB (polyvinyl-butyral) has the highest damping loss factor value of 37%. The “Material C” backlight with acoustic PVB is the best among all the lightweight alternatives and brings 29% weight reduction without any NVH degradation. Statistical Energy Analysis (SEA) results also indicate that it is possible to eliminate the NVH degradation by using glazing material having high material damping properties or using laminated panels having damping loss values in the range of 6% to 20%. In this paper, we only address the weight reduction and NVH performance of light weight glazing materials but not the costs or any potential assembly procedure changes.

Damping Properties and Mechanism of 0-3 PMN/CB/EP Composites

2009 ◽  
Vol 66 ◽  
pp. 45-48 ◽  
Author(s):  
Min Xian Shi ◽  
Zhi Xiong Huang ◽  
Tao Wei ◽  
Lian Meng Zhang
Keyword(s):  
Carbon Black ◽  
Epoxy Resin ◽  
Loss Factor ◽  
Piezoelectric Ceramic ◽  
Volume Resistivity ◽  
Damping Properties ◽  
Casting Method ◽  
Conductive Carbon Black ◽  
Damping Loss Factor ◽  
Peak Value

0-3 piezoelectric ceramic PMN/conductive carbon black(CB)/epoxy resin(EP) composites were prepared by resin casting method. The electric and damping properties of PMN/CB/EP composites were detected. The volume resistivity of the composites decreases with the addition of conductive carbon black, and the composites experience transition from insulator to semiconductor when the CB content is 6% weight of the resin in the composites. Damping loss factor-temperature curves scanned by DMA showed that the peak value of damping loss factor(tanmax), the loss factor area(TA) and the damping temperature range(T) of the composites increase and reach to maximum values when CB content is 6% weight of EP resin, then drop a little with CB contents further increasing. When CB was just at threshold content 6% of epoxy weight the composite converts from insulator to semiconductor with the volume resistivity being about 108 Ωm and piezo-damping mechanism plays efficiently.

Damping Loss Factor Estimation for Test-Based Vehicle SEA Modeling

2001 ◽  
Author(s):  
Jae-Hak Woo ◽  
Xiandi Zeng
Keyword(s):  
Loss Factor ◽  
Bias Error ◽  
Reverberation Time ◽  
Frequency Range ◽  
Air Cavity ◽  
Damping Loss Factor ◽  
Factor Estimation

Abstract In the test-based SEA models, the major parameters are measured or estimated from measured quantities. One of the parameters is Damping Loss Factor (DLF) of the air (passenger) cavity of a vehicle. In the SEA model, the air cavity is divided into several sub-cavities. The required DLF for each sub-cavity can be calculated from the reverberation time (T60) measured in that sub-cavity in the vehicle. However, if nothing is done to separate one sub-cavity from other sub-cavities in the T60 measurement in the vehicle, the measured T60 for that sub-cavity is the T60 of the whole air cavity. When the resulted DLF is used in SEA model of that sub-cavity, it is the DLF of the whole air cavity that is used for a sub-cavity, which will result in an over/under-damped. Thus, the prediction from such a SEA model will have bias error especially in the higher frequency range. This has been seen in the results of a vehicle SEA model. In this paper, a method is proposed to estimate the DLF of each sub-cavity based on the T60 of the whole air cavity. When these estimated DLF’s are used in the SEA model for each sub-cavity, the correlation in SEA model was improved by 2.5∼3 dB above 1kHz.

Electric and Damping Properties of PU Based IPNs-BaTiO3 Nanocomposites

2007 ◽  
Vol 336-338 ◽  
pp. 118-120
Author(s):  
Dong Yan Tang ◽  
Zheng Jin ◽  
Liang Sheng Qiang
Keyword(s):  
Dielectric Properties ◽  
Loss Factor ◽  
Synergistic Effects ◽  
Electric Properties ◽  
Damping Properties ◽  
Damping Property ◽  
Frictional Damping ◽  
Damping Loss Factor ◽  
The Relationship

(PU/UP IPNs)-BaTiO3 nanocomposites with different amounts of BaTiO3 nanopowder are prepared and polarized. The ferroelectric and dielectric properties are detected and the relationship between electric properties and damping properties are discussed in detail. Results indicate that the synergistic effects can be created successfully by elastic damping of polymer, frictional damping of BaTiO3, and piezoelectric damping of nanocomposites after poling. The nanocomposites increase the damping property evidently and sustain mostly ferroelectric and dielectric characters of inorganic phase. The introduction of BaTiO3 into IPNs decreases the resistivity, and this has advantages to enlarge the damping loss factor (tanδ).

Sign in / Sign up

Export Citation Format

Share Document