scholarly journals Investigation of Mechanical and Damping Performances of Cylindrical Viscoelastic Dampers in Wide Frequency Range

Actuators ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 71
Author(s):  
Teng Ge ◽  
Xing-Huai Huang ◽  
Ying-Qing Guo ◽  
Ze-Feng He ◽  
Zhong-Wei Hu
Keyword(s):  
Mechanical Properties ◽  
Energy Consumption ◽  
Loss Factor ◽  
Dynamic Mechanical Properties ◽  
Wide Frequency Range ◽  
Equivalent Stiffness ◽  
Frequency Range ◽  
Viscoelastic Damper ◽  
Equivalent Damping ◽  
Viscoelastic Dampers

This paper aims to develop viscoelastic dampers, which can effectively suppress vibration in a wide frequency range. First, several viscoelastic materials for damping performance were selected, and different batches of cylindrical viscoelastic dampers were fabricated by overall vulcanization. Second, the dynamic mechanical properties of the cylindrical viscoelastic dampers under different amplitudes and frequencies are tested, and the hysteretic curves under different loading conditions are obtained. Finally, by calculating the dynamic mechanical properties of the cylindrical viscoelastic dampers, the energy dissipation performance of these different batches of viscoelastic dampers is compared and analyzed. The experimental results show that the cylindrical viscoelastic damper presents a full hysteretic curve in a wide frequency range, in which the maximum loss factor can reach 0.57. Besides, the equivalent stiffness, storage modulus, loss factor, and energy consumption per cycle of the viscoelastic damper raise with the frequency increasing, while the equivalent damping decreases with the increase of frequency. When the displacement increases, the energy consumption per cycle of the viscoelastic damper rises rapidly, and the equivalent stiffness, equivalent damping, storage modulus, and loss factor change slightly.

scholarly journals Study on dynamic mechanical properties of O-ring with large ring diameter ratio based on metal rubber

2021 ◽  
Author(s):  
Xiaoyuan Zheng ◽  
Zhiying Ren ◽  
Yangyang Yang ◽  
Hongbai Bai ◽  
Yi Liang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Energy Consumption ◽  
Loss Factor ◽  
Engineering Application ◽  
Dynamic Mechanical Properties ◽  
Diameter Ratio ◽  
Range Analysis ◽  
Dynamic Mechanical ◽  
Large Ring ◽  
Metal Rubber

Abstract The demand for High temperature resistant metal rubber seals (MRS) with large ring-to-diameter ratio is very urgent in the industrial field. In this work, an O-type MRS with a large ring-to-diameter ratio was developed by embedding the spiral network metal rubber into the stainless steel ring with a special preparation process. The effects of frequency, porosity, and amplitude on the dynamic experimental performance of O-type MRS were studied in detail. The mechanical properties of the MRS were characterized by dynamic tests, and the damping sensitivity were analyzed by orthogonal tests. The results show that MRS has better stability under different frequencies of vibration. The energy consumption and loss factor of the sample increase with increases of porosity. With an increase in loading amplitude, the energy consumption and loss factor of the same porosity test sample increases, whereas the dynamic average stiffness of the specimen gradually decreases. Furthermore, the range analysis of the orthogonal experiment shows that the factors affecting the damping performance of the seal are porosity>amplitude>frequency. This study fills in the dynamic mechanical properties of O-shaped MRS, and provides a certain foundation for the engineering application of O-shaped MRS.

Study on mechanical properties of high damping viscoelastic dampers

2019 ◽  
Vol 22 (14) ◽  
pp. 2925-2936 ◽  
Author(s):  
Yun Chen ◽  
Chao Chen ◽  
Qianqian Ma ◽  
Huanjun Jiang ◽  
Zhiwei Wan
Keyword(s):  
Mechanical Properties ◽  
Shear Strain ◽  
Strain Amplitude ◽  
Hysteretic Behavior ◽  
Loading Frequency ◽  
Equivalent Stiffness ◽  
Viscoelastic Dampers ◽  
Wide Range ◽  
High Damping Rubber ◽  
Stiffness And Damping

The mechanical properties of the viscoelastic damper made of high damping rubber produced in China are investigated in order to provide the basis for its application. At first, the test on material properties of high damping rubber is conducted. The Mooney–Rivlin model, the Yeoh model and the Prony series are applied for simulating the nonlinear behavior of the high damping rubber with the aid of software ABAQUS. Then, three viscoelastic dampers with different sizes are tested under cyclic loading. The effects of strain amplitude and loading frequency on hysteretic behavior of dampers are analyzed. Viscoelastic dampers possess large deformation capability, stable energy-dissipation capacity and good fatigue-resisting property. The effect of strain amplitude is much more significant than loading frequency. The hysteretic behavior of the dampers is simulated by the Bouc–Wen model and the model of the equivalent stiffness and damping, respectively. The prediction results by using the Bouc–Wen model are in good agreement with the experimental results, which indicates that the Bouc–Wen model is applicable to simulate the mechanical properties of high damping viscoelastic dampers with a wide range of shear strain. As to the model of equivalent stiffness and damping, it has the advantages of clear concept and simple calculation. However, the good accuracy of prediction can be obtained only when the shear strain is not greater than 60%.

Dielectric Properties of Eucalyptus urophylla Under an Ultra-Wide Frequency Range

2020 ◽  
Vol 12 (8) ◽  
pp. 1236-1241
Author(s):  
He Xia ◽  
Wang Yong ◽  
Li Yunyan ◽  
Wei Yanqiang ◽  
Quan Peng ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Dielectric Loss ◽  
Dielectric Permittivity ◽  
Loss Factor ◽  
Wide Frequency Range ◽  
Dielectric Loss Factor ◽  
Regression Equations ◽  
Eucalyptus Urophylla ◽  
Frequency Range ◽  
Tangential Directions

Dielectric properties of Eucalyptus urophylla wood were measured by using a network analyzer over an ultrawide frequency range between 0.2 GHz and 20 GHz. The effects of moisture content (MC), temperature and frequency on the dielectric permittivity and the dielectric loss factor of Eucalyptus urophylla were investigated along different grain directions. The results showed that the dielectric permittivity along with the dielectric loss factor increased significantly with the elevation in MC. At the frequency of 2380 MHz with the MC increasing from 0% to 100%, the dielectric permittivity along different grain directions (including longitudinal, radial and tangential directions) increased by 180%, 110% and 112%, respectively, while the loss factor along these three directions increased by 1642%, 3703% and 5058%, respectively. In addition, the increase in dielectric properties of Eucalyptus urophylla wood was determined with the temperature elevating. When the temperature elevated from 20 °C to 140 °C, the dielectric permittivity at 2380 MHz along the longitudinal, radial and tangential directions, increased by 19%, 14% and 15%, respectively, while the loss factor increased by 133% at most. As the radio frequency increased, the dielectric permittivity of wood decreased. Regression equations satisfactorily described the dielectric properties of wood along different grain directions with different moisture contents.

Experimental Investigation on the Electrical and Dynamic Mechanical Properties of PMN/Electrically Conductive Carbon Black/Butyl Composites

2007 ◽  
Vol 351 ◽  
pp. 171-175 ◽  
Author(s):  
Yan Bing Wang ◽  
Zhi Xiong Huang ◽  
Yan Qin ◽  
Ming Du ◽  
Lian Meng Zhang
Keyword(s):  
Mechanical Properties ◽  
Carbon Black ◽  
Loss Factor ◽  
Dynamic Mechanical Properties ◽  
Polymer Materials ◽  
Electrically Conductive ◽  
Dynamic Mechanical ◽  
Temperature Range ◽  
Conductive Carbon Black ◽  
Three Phase

In this paper, a three-phase composite with electrically conductive carbon black (ECCB) and piezoelectric ceramic particles, PMN, embedded into butyl (PMN/ECCB/IIR) was prepared by simple blend and mold-press process. Dynamic mechanical properties with various ECCB loading were tested by dynamic mechanical analysis (DMA). DMA shows that the ECCB loading has remarkable effect on the dynamic mechanical properties of the three-phase composite. The temperature range of loss factor (tanδ) above 0.3 the composite was broadened by almost 100°C and the maximum of loss factor shifts to higher temperature in the testing temperature range respectively with increasing the ECCB loading. The piezoelectric damping theory was used to explain the experimental results. The three-phase composites with proper composition can be used as high damping polymer materials.

scholarly journals Center Impedance Method for Estimating Complex Modulus with Wide Frequency Range and Large Loss Factors

2021 ◽  
Vol 2021 ◽  
pp. 1-23
Author(s):  
Ryuzo Horiguchi ◽  
Yoshiro Oda ◽  
Keito Sato ◽  
Hiroto Kozuka ◽  
Takao Yamaguchi
Keyword(s):  
Loss Factor ◽  
Wide Frequency Range ◽  
Frequency Function ◽  
Single Frequency ◽  
Impedance Method ◽  
Frequency Range ◽  
Simple Method ◽  
Large Loss ◽  
Mobility Data ◽  
Loss Factors

A simple method for determining viscoelasticity over a wide frequency range using the frequency response function (FRF) mobility obtained by the center impedance method is presented. As user data comprise the FRF between the velocity of the excitation rod and excitation force, it is challenging to separate the signal and noise. Our proposed method is based on the FRF obtained from the analytical solution of the equation of motion of the viscoelastic beam and relationship between the complex wavenumber (real wavenumber and attenuation constant) of flexural wave and viscoelasticity. Furthermore, a large loss factor can be handled over a wide frequency range without using the half-power bandwidth. In this study, actual FRF mobility data containing noise were processed using preprocessing, inverse calculation, and postprocessing. Preprocessing removed low-coherence data, compensates for the effects of instrument gain, and transformed the FRF into its dimensionless equivalent. Then, inverse calculations were used to solve the mobility equation and determine the complex wavenumber. In postprocessing, the complex wavenumber obtained by the inverse calculation was curve fitted using functions with mechanical significance. Consequently, the storage modulus based on the curve-fitted complex wavenumber was a monotonically increasing frequency function. The loss factor had a smooth frequency dependence such that it has the maximum value at a single frequency. The proposed method can be applied to composite materials, where the application of time-temperature superposition is challenging. We utilized the measured FRF mobility data obtained over a duration of several seconds, and this method can also be applied to materials with large loss factors of 1 or more.

Thermal, mechanical, and dielectric properties of epoxy resin modified using carboxyl-terminated polybutadiene liquid rubber

2016 ◽  
Vol 49 (4) ◽  
pp. 281-297 ◽  
Author(s):  
Lina Dong ◽  
Wenying Zhou ◽  
Xuezhen Sui ◽  
Zijun Wang ◽  
Peng Wu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Dissipation Factor ◽  
Wide Frequency Range ◽  
Carboxyl Groups ◽  
Frequency Range ◽  
Two Phase ◽  
Liquid Rubber ◽  
The Impact ◽  
Thermal Stability Of

Epoxy (Ep) resin modified with carboxyl-terminated polybutadiene (CTPB) liquid rubber was investigated in this study. Fourier transform infrared verified the chemical reactions between oxirane ring of Ep and carboxyl groups of CTPB using benzyldimethylamine as a catalyst. The decrease of the thermal stability could be due to the lower thermal stability of CTPB compared with that of pure Ep. The mechanical results showed that CTPB-modified Ep was superior to that of the pure Ep, and the best overall mechanical properties were normally achieved with 20 phr of CTPB content. The impact strength of the system containing 20 phr CTPB increased by 193% due to the two-phase nature of the system. The dielectric constant and dissipation factor of the modified Ep obviously declined with the CTPB content compared with pure Ep, for instance, the dissipation factor remained less than 0.02 in wide frequency range.

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