An Experimental Evaluation of Smart Damping Materials for Reducing Structural Noise and Vibrations

2001 ◽  
Vol 123 (4) ◽  
pp. 533-535 ◽  
Author(s):  
Mehdi Ahmadian ◽  
Kristina M. Jeric ◽  
Daniel J. Inman
Keyword(s):  
Experimental Evaluation ◽  
Industrial Applications ◽  
Viscoelastic Damping ◽  
Minimal Amount ◽  
Structural Noise ◽  
Test Results ◽  
Test Rig ◽  
Test Plate ◽  
Multiple Frequencies ◽  
Damping Materials

An experimental evaluation of the benefits of smart damping materials in reducing structural noise and vibration is presented. The construction of a special test rig for measuring both vibrations and structure-borne noise is discussed. Next, the application of smart damping materials, specifically piezoceramics with electrical shunts, in reducing the vibrations of a test plate is discussed. It is shown that the smart damping materials are able to effectively reduce the vibration peaks at multiple frequencies, with minimal amount of added weight to the structure, as compared to passive viscoelastic damping materials. Further, the test results show that the structure-borne noise at the vibration peaks is substantially reduced with the smart damping materials. The results indicate the viability of smart damping materials for many industrial applications where reducing noise and vibrations is desired, with minimal amounts of added weight.

An Experimental Evaluation of Smart Damping Materials for Reducing Structural Noise and Vibrations

1999 ◽  
Author(s):  
Mehdi Ahmadian ◽  
Kristina M. Jeric ◽  
Daniel J. Inman
Keyword(s):  
Experimental Evaluation ◽  
Industrial Applications ◽  
Viscoelastic Damping ◽  
Minimal Amount ◽  
Structural Noise ◽  
Test Results ◽  
Test Rig ◽  
Test Plate ◽  
Multiple Frequencies ◽  
Damping Materials

Abstract An experimental evaluation of the benefits of smart damping materials in reducing structural noise and vibration is presented. The construction of a special test rig for measuring both vibrations and structure-borne noise is discussed. Next, the application of smart damping materials, specifically piezoceramics with electrical shunts, in reducing the vibrations of a test plate is discussed. It is shown that the smart damping materials are able to effectively reduce the vibration peaks at multiple frequencies, with minimal amount of added weight to the structure, as compared to passive viscoelastic damping materials. Further, the test results show that the structure-borne noise at the vibration peaks is substantially reduced with the smart damping materials. The results indicate the viability of smart damping materials for many industrial applications where reducing noise and vibrations is desired with minimal amounts of added weight, or at frequencies below the effective range of passive damping materials.

High Frequency Vibration Analysis of Automotive Body Panels with Damping Materials

2010 ◽  
Vol 36 ◽  
pp. 293-296
Author(s):  
Yoshio Kurosawa ◽  
Takao Yamaguchi
Keyword(s):  
High Frequency ◽  
Large Scale ◽  
The Body ◽  
Viscoelastic Damping ◽  
Fe Model ◽  
Test Results ◽  
Automotive Body ◽  
Modal Damping ◽  
Practical Tool ◽  
Damping Materials

We have developed a technique for estimating vibrations of an automotive body structures with viscoelastic damping materials using large-scale finite element (FE) model, which will enable us to grasp and to reduce high-frequency road noise（200～500Hz）. In the new technique, first order solutions for modal loss factors are derived applying asymptotic method. This method saves calculation time to estimate modal damping as a practical tool in the design stages of the body structures. Frequency responses were calculated using this technique and the results almost agreed with the test results. This technique can show the effect of the viscoelastic damping materials on the automotive body panels, and it enables the more efficient layout of the viscoelastic damping materials. Further, we clarified damping properties of the automotive body structures under coupled vibration between frames and panels with the viscoelastic damping materials.

scholarly journals Tribological Characteristics of Natural Fiber Reinforced Polyester Hybrid Composites

2019 ◽  
Vol 8 (10) ◽  
pp. 947-952 ◽  
Keyword(s):  
Surface Temperature ◽  
Natural Fiber ◽  
Hybrid Composites ◽  
Wear Behavior ◽  
Load Capacity ◽  
Industrial Applications ◽  
Test Results ◽  
Test Rig ◽  
Simplified Method ◽  
Gear Surface Temperature

In order to investigate the wear behavior and tooth damage of Madar and Bauhinia Racemosa fibers reinforced polyester, the composite gears were fabricated with varying the fiber weight percentages of 5%, 10%, 15% and 20%. This paper explores the rolling and sliding of the composite gears running against nylon gear with a simplified method of analyzing and understanding the wear and tooth damage. Tests were conducted without external lubrication over a range of loads 4Nm, 8Nm,12Nm and 16Nm using a gear test rig. The test results of composite gears are compared with unreinforced polyester gear (URPE). It was found that the surface temperature was the primary factor affecting the wear rate and an initial relationship between gear surface temperature and load capacity. This composite can be useful for automobile and industrial applications.

Educational Model for the Kinematic Study of Non-Circular Gears

2013 ◽  
Vol 332 ◽  
pp. 297-304
Author(s):  
Liviu Ciupitu
Keyword(s):  
Numerical Methods ◽  
Industrial Applications ◽  
Point Of View ◽  
Spur Gears ◽  
Test Rig ◽  
Educational Model ◽  
Educational Test ◽  
Kinematic Study ◽  
Variation Curve ◽  
Noncircular Gears

The noncircular gears are used more and more in industrial applications. The paper presents an educational test rig for the kinematic study of non-circular gears. Two gears are studied from kinematic theoretically point of view: a gear with identically oval spur gears and another gear with identically elliptical spur gears, and simulation diagrams are presented. As for the testing rig, a gear with identically oval spur gears has been used. The researchers are able to draw with high precision the variation curve of output angle with respect to input angle. By using numerical methods for integration and differentiation other diagrams could be drawn and a comparation with simulation diagrams could be made.

A Mechatronic Approach to Compact Fluid Disc Valve Design

1995 ◽  
Vol 209 (2) ◽  
pp. 115-125
Author(s):  
G A Parker ◽  
Y B Sun
Keyword(s):  
Low Cost ◽  
Dynamic Performance ◽  
Operating Mode ◽  
Industrial Applications ◽  
Test Results ◽  
Valve Design ◽  
Electromagnetic Characteristics ◽  
High Control ◽  
Fail Safe ◽  
Pilot Valve

The work presented in this paper deals mainly with a mechatronic approach to compact disc valve design and concentrates on improvements to the disc valve electromagnetic characteristics, the diaphragm design and the dynamic performance. A novel diaphragm-disc force motor has been successfully developed incorporating a pair of permanent ring magnets. It has the advantages of low electric power consumption at the null position, dual-lane electrical structure for fail-safe operation, high control accuracy and should be competitive with existing torque motors due to its low cost and simple construction. The research involved designing and testing a prototype disc pilot valve with a dual-lane operating mode. The test results showed that the valve has satisfactory static and dynamic characteristics for industrial applications.

High Frequency Vibration Analysis of Automotive Bodies With Panels That Have Attached Viscoelastic Layers

2003 ◽  
Author(s):  
Yoshio Kurosawa ◽  
Hideki Enomoto ◽  
Shuji Matsumura ◽  
Takao Yamaguchi
Keyword(s):  
High Frequency ◽  
Large Scale ◽  
The Body ◽  
Viscoelastic Damping ◽  
Fe Model ◽  
Automotive Body ◽  
Modal Damping ◽  
Practical Tool ◽  
Damping Materials ◽  
Viscoelastic Layers

A technique has been developed for estimating vibrations of an automotive body structures with viscoelastic damping materials using large-scale finite element (FE) model, which will enable us to grasp and to reduce high-frequency road noise (200∼500Hz). In the new technique, first order solutions for modal loss factors are derived applying asymptotic method. This method saves calculation time to estimate modal damping as a practical tool in the design stages of the body structures. Frequency responses were calculated using this technique and the results almost agreed with the test results. This technique can show the effect of the viscoelastic damping materials on the automotive body panels, and it enables the more efficient layout of the viscoelastic damping materials. Further, we clarified damping properties of the automotive body structures under coupled vibration between frames and panels with the viscoelastic damping materials.

Systematic Experimental Investigation of Dielectric Electroactive Polymers Using a Custom-Built Uniaxial Tensile Test Rig

2015 ◽  
Author(s):  
Micah Hodgins ◽  
Alexander York ◽  
Stefan Seelecke
Keyword(s):  
Pure Shear ◽  
Tensile Force ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Specimen Preparation ◽  
Testing Device ◽  
Test Results ◽  
Test Rig ◽  
Geometry Test

This work presents the design, fabrication and testing of a comprehensive DEAP test station. The tester is designed to perform tensile tests of planar DEAPs while measuring quantities such as tensile force, stretch, film thickness and voltage/current. The work details the specimen preparation and how the specimen is placed in the clamps. While the assembly process is performed by hand features were built-in to the design of the specimen frame and clamps to enable reliable placement and specimen geometry. Test results of the pure-shear specimen demonstrated good performance of the testing device. Although the electrode surface was rough the thickness stretch was evident during the stretching/actuation of the DEAP actuator.

scholarly journals Thermal Comfort Evaluation of Rooms Installed with STPV Windows

Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 808 ◽  
Author(s):  
Hao Tian ◽  
Wei Zhang ◽  
Lingzhi Xie ◽  
Zhichun Ni ◽  
Qingzhu Wei ◽  
...  
Keyword(s):  
Thermal Comfort ◽  
Indoor Environment ◽  
Thermal Sensation ◽  
Test Results ◽  
Test Unit ◽  
Maximum Difference ◽  
Test Rig ◽  
Comfort Evaluation ◽  
The Difference ◽  
Better Than

Thermal comfort is an important aspect to take into consideration for the indoor environment of a building integrated with a semi-transparent Photovoltaics (STPV) system. The thermal comfort of units with photovoltaic windows and that of conventional windows, which is an ordinary without PV, were evaluated via on-site tests and questionnaires. Using the thermal comfort investigation of the test rig, the maximum difference in air temperature was found to be around 5 °C between test unit and comparison unit. The predicted mean vote (PMV)–predicted percentage dissatisfied (PPD) value of the test unit was better than that of the comparison unit. It was observed that on sunny days, the PMV value ranged from 0.2 (nature) to 1.3 (slightly warm) in the test unit, and that of the comparison unit was 0.7 (slightly warm) to 2.0 (warm), thereby providing better thermal comfort, especially during mornings. The maximum difference in PPD values was found to reach 27% between the two units at noon. On cloudy days, the difference was negligible, and the thermal sensation between the foot and the head were almost the same. Fifty respondents were asked to complete a carefully designed questionnaire. The thermal sensation of the test unit was better than that of comparison unit, which corresponded with the test results. Thermal, lighting, acoustic, and other environment comfort scores were combined, and the acceptance of the test unit with the STPV windows was found to be 73.8%. The thermal sensation difference between men and women was around 5%. Thus, during summer, STPV windows can improve the thermal comfort and potentially reduce the air-conditioning load.

An Investigation of the Flow Characteristics and of Losses in Radial Nozzle Cascades

1984 ◽  
Vol 106 (2) ◽  
pp. 502-509 ◽  
Author(s):  
S. G. R. Hashemi ◽  
R. J. Lemak ◽  
J. A. Owczarek
Keyword(s):  
Flow Characteristics ◽  
Leading Edge ◽  
Injection Technique ◽  
Test Results ◽  
Test Rig ◽  
Water Test ◽  
Edge Vortex ◽  
Loss Coefficients ◽  
Radial Nozzle ◽  
Nozzle Blade

A study was made of the flow in radial nozzle cascades using an air test rig and a water test rig. In the air test rig, three cobra probes were used in circumferential and spanwise traverses to determine the total pressure variations in the flow field at three radii downstream of the nozzles at which static pressure was also measured. The tests were made on two sets of nozzle blades having heights of 0.148 in. (0.376 cm) and 0.200 in. (0.508 cm), at trailing edge angles (measured from circumferential direction) of 15, 20, and 25 deg, and at two flow Mach numbers of approximately 0.2 and 0.35. The test results presented in this paper, in the form of loss coefficients and flow angles, were flow-weighted and averaged. Flow visualization in the air test rig was made on the walls bounding the nozzle blades using the graphite power-oil mixture technique. Additional tests were made on the water test rig using dye injection technique. Photographs were obtained showing clearly formation of secondary flow around each nozzle blade in the form of the leading edge vortex. The test results confirm the existence of the leading edge vortices reported peviously, and extend their study to the radial nozzle cascades.

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