Small Amplitude Dynamic Properties of Ni48Ti46Cu6 SMA Ribbons: Experimental Results and Modelling

2006 ◽  
Vol 128 (3) ◽  
pp. 260-267 ◽  
Author(s):  
C. Remillat ◽  
M. R. Hassan ◽  
F. Scarpa
Keyword(s):  
Fractional Derivative ◽  
Loss Factor ◽  
Small Amplitude ◽  
Dynamic Properties ◽  
Low Frequency ◽  
Viscoelastic Damping ◽  
Compact Representation ◽  
Damping Capacity ◽  
Frequency Range ◽  
Thermally Induced

This work illustrates viscoelastic testing and fractional derivative modelling to describe the thermally induced transformation equivalent viscoelastic damping of NiTiCu SMA ribbons. NiTiCu SMA ribbons have been recently evaluated to manufacture novel honeycombs concepts (conventional and negative Poisson’s ratio) in shape memory alloys for high damping and deployable sandwich antennas constructions. The dynamic mechanical thermal analysis (DMTA) test has been carried out at different frequencies and temperatures, with increasing and decreasing temperature gradients. Thermally induced transformations (austenitic and martensitic) provide damping peaks at low frequency range excitations. On the opposite, the storage moduli are not affected by the harmonic pulsation. As the SMA ribbon increases its stiffness, the damping capacity reduces, and the loss factor drops dramatically at austenite finish temperature. The fractional derivative models provide a compact representation of the asymmetry of the peak locations, as well as the storage modulus change from martensite to austenite phases.

Research on the dynamic characteristic of semi-active hydraulic damping strut

2019 ◽  
Vol 234 (6) ◽  
pp. 1779-1791 ◽  
Author(s):  
Daoyong Wang ◽  
Wencan Zhang ◽  
Mu Chai ◽  
Xiaguang Zeng
Keyword(s):  
Degrees Of Freedom ◽  
Dynamic Stiffness ◽  
Low Frequency ◽  
Maxwell Model ◽  
Friction Model ◽  
Damping Capacity ◽  
Frequency Range ◽  
Stiffness Model ◽  
Rubber Bushing

To reduce the vibration and shock of powertrain in the process of engine key on/off and vehicle in situ shift, a novel semi-active hydraulic damping strut is developed. The purpose of this paper is to study and discuss the dynamic stiffness model of the semi-active hydraulic damping strut. In this study, the dynamic characteristics of semi-active hydraulic damping strut were analyzed based on MTS 831 test rig first. Then, the dynamic stiffness model of semi-active hydraulic damping strut was established based on 2 degrees of freedom vibration system. In this research, a linear, fractional derivative and friction model was used to represent the nonlinear rubber bushing characteristic; the Maxwell model was used to describe the semi-active hydraulic damping strut body model; and the parameters of rubber bushing and semi-active hydraulic damping strut body were identified. The dynamic stiffness values were calculated with solenoid valve energized and not energized at amplitudes of 1 mm and 4 mm, which were consistent with experimental results in low-frequency range. Furthermore, the simplified dynamic stiffness model of the semi-active hydraulic damping strut was discussed, which showed that bushing can be ignored in low-frequency range. Then, the influence of equivalent spring stiffness, damping constant, and rubber bushing stiffness on the stiffness and damping capacity of the semi-active hydraulic damping strut were analyzed. Finally, the prototype of the semi-active hydraulic damping strut was developed and designed based on the vehicle in situ shift and engine key on/off situations, and experiments of the vehicle with and without semi-active hydraulic damping strut were carried out to verify its function.

scholarly journals Dielectric Properties of Ternary ( ) ( )x ( ) x ZnO MgO PO 30 2 5 70− (x = 5, 8, 13) Glasses

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
S. F. Khor ◽  
Z. A. Talib ◽  
W. M. Daud ◽  
H. A. A. Sidek ◽  
W. M. M. Yunus ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Dielectric Permittivity ◽  
Empirical Data ◽  
Loss Factor ◽  
Low Frequency ◽  
Frequency Range ◽  
Melt Quenching ◽  
Dipolar Relaxation ◽  
Temperature Range

(ZnO)30(MgO)x(P2O5)70-x glasses of the composition x = 5, 8 and 13 mol % have been prepared by melt quenching technique. The dielectric permittivity (89) and loss factor (8:) were measured in the frequency range from 0.01 Hz to 1 MHz and in the temperature range 303 to 573 K . From the results there are evidence of dipolar relaxation occurring between 103 – 106 Hz while at low frequency the spectrum is dominated by dc conduction which manifested by the 1/@ slope of loss factor plot. Value of the relaxing frequency (@p) plotted against 1/T shows one electrical transportation mechanism. The empirical data was sufficiently fitted by using Harviliak-Negami equation.

Augmentation of low frequency damping via hydrogen-doping in a hybrid shape memory alloy composite

2021 ◽  
pp. 1045389X2110390
Author(s):  
Shashank Nagrale ◽  
Avery D Brown ◽  
Charles E Bakis ◽  
Reginald F Hamilton
Keyword(s):  
Loss Factor ◽  
Volume Fraction ◽  
Dynamic Properties ◽  
Low Frequency ◽  
Fiber Reinforced Polymer ◽  
Helicopter Blades ◽  
Reinforced Polymer ◽  
Hydrogen Doping ◽  
Cfrp Composite ◽  
Niti Wires

Carbon fiber reinforced polymer (CFRP) composites hybridized with hydrogen-doped NiTi wires can be used to design structures requiring high stiffness and high damping in the low frequency range, such as helicopter blades. The current work investigates aging and hydrogen-doping for high damping without hydrogen embrittlement. We establish a hydrogenation treatment that (i) results in a response that is repeatable in the martensitic phase and after exposure to composite processing temperatures and (ii) increases the loss factor in NiTi wires by nearly 470%. By embedding H-doped wires exhibiting the highest damping into the interlayers of a [0/±45]s carbon/epoxy laminate at a volume fraction of 0.1, the hybrid NiTi-CFRP composite loss factor increases by 170%. The measured dynamic properties were found to be close to micromechanical predictions based on the properties of the NiTi and CFRP.

Researches on a roller dempfying properties when vibrating a cutting instrument in a bandsaw equipment

2016 ◽  
Vol 6 (3) ◽  
pp. 202-206
Author(s):  
Чепелева ◽  
Marina Chepeleva ◽  
Чепелев ◽  
Stanislav Chepelev ◽  
Чернышков ◽  
...  
Keyword(s):  
Mathematical Description ◽  
Dynamic Properties ◽  
Superposition Principle ◽  
Low Frequency ◽  
Harmonic Vibration ◽  
Experimental Methodology ◽  
Mathematical Apparatus ◽  
Frequency Range ◽  
New Material ◽  
To Receive

The article deals with the usage of new material – the pressed wood together with modifi-cators to detect the dempfying properties to improve a soothing roller in a bandsaw equipment WoodMizerLT 15. The article stresses the idea of the experimental methodology to receive data for the future, further mathematical description of dynamic properties of the bandsaw equipment in low-frequency range of harmonic vibration. The superposition principle is used for the above-mentioned object, so the mathematical apparatus is limited by arrival.

Indenter–Foam Dampers Inspired by Cartilage: Dynamic Mechanical Analyses and Design

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Guebum Han ◽  
Utku Boz ◽  
Lejie Liu ◽  
Corinne R. Henak ◽  
Melih Eriten
Keyword(s):  
Scaling Laws ◽  
Pore Diameter ◽  
Low Frequency ◽  
Mechanical Analysis ◽  
Solid Matrix ◽  
Damping Capacity ◽  
Simulation Studies ◽  
Frequency Range ◽  
Dynamic Mechanical ◽  
Simple Scaling

Abstract Articular cartilage is a thin layer of a solid matrix swollen by fluid, and it protects joints from damage via poroviscoelastic damping. Our previous experimental and simulation studies showed that cartilage-like poroviscoelastic damping could widen the range of damping methods in a low-frequency range (<100 Hz). Thus, the current study aimed to realize cartilage-like damping capacity by single- and two-indenter–foam poroviscoelastic dampers in a low-frequency range. Multiple single-indenter–foam dampers were designed by combining foam sheets with different pore diameters and indenters with different radii. Their damping capacity was investigated by dynamic mechanical analysis in a frequency range of 0.5–100 Hz. Single-indenter–foam dampers delivered peak damping frequencies that depended on the foam’s pore diameter and characteristic diffusion length (contact radii). Those dampers maximize the damping capacity at the desired frequency (narrowband performance). A mechanical model combined with simple scaling laws was shown to relate poroelasticity to the peak damping frequencies reasonably well. Finally, combinations of single-indenter–foam dampers were optimized to obtain a two-indenter–foam damper that delivered nearly rate-independent damping capacity within 0.5–100 Hz (broadband performance). These findings suggested that cartilage-like poroviscoelastic dampers can be an effective mean of passive damping for narrowband and broadband applications.

scholarly journals Fractional-Derivative Maxwell Kelvin Model for “5+4” Viscoelastic Damping Wall Subjected to Large Deformation

2016 ◽  
Vol 2016 ◽  
pp. 1-11
Author(s):  
Junhong Xu ◽  
Aiqun Li ◽  
Yang Shen
Keyword(s):  
Energy Dissipation ◽  
Fractional Derivative ◽  
Large Deformation ◽  
Dynamic Properties ◽  
Loss Modulus ◽  
Hysteresis Loops ◽  
Maxwell Model ◽  
Viscoelastic Damping ◽  
Building Structures ◽  
Kelvin Model

Considering the larger vibration amplitude and several viscoelastic material layers, a fractional-derivative Maxwell Kelvin (FDMK) viscoelastic mechanical model is proposed for “5+4” viscoelastic damping wall, which is used for vibration control of building structures. The development of the model is based on in-parallel combination of fractional Maxwell model and fractional Kelvin model. The proposed model is experimentally validated and very good agreement between predicted and experimental results was obtained. The results confirm that the FDMK model is accurate in simulating the hysteresis properties of the “5+4” viscoelastic damping wall under large deformation. From the areas of the experimental and theoretical hysteresis loops, under 300% strain, the predicted result is the most accurate in prediction of the energy dissipation and the second is the prediction under 450% strain. Moreover, from the comparisons of dynamic properties (storage modulus, loss modulus, etc.), the FDMK model works satisfactorily. The FDMK model is more sensitive in energy dissipation than in energy storage.

Experimental Investigation on Dynamic Mechanical Behavior of the Elastic Ring Support With Metal Rubber

2013 ◽  
Author(s):  
Yanhong Ma ◽  
Haixiong Zhu ◽  
Dayi Zhang ◽  
Jie Hong
Keyword(s):  
Experimental Investigation ◽  
Loss Factor ◽  
Dynamic Properties ◽  
Dynamic Stiffness ◽  
Rotor System ◽  
Damping Capacity ◽  
Strong Nonlinearity ◽  
Elastic Ring ◽  
Metal Rubber ◽  
Motion Amplitude

A novel oil-free elastic damping support for rotor system is presented here which is combined of Elastic Ring (ER) and Metal Rubber (MR) named ERMR support for short. The ERMR support is an alternative of the traditional elastic damping support combined of squirrel cage and Squeeze Film Damper (SFD). The dynamic characteristics of the support were investigated and discussed, as well as the rotordynamic performances of the rotor system with the ERMR support. Frequency sweeping experiments with different motion amplitudes were conducted to investigate the dynamic stiffness and damping properties of the support. Results show that both the structural stiffness and equivalent viscous damping of the support decrease significantly with the motion amplitude when the amplitude is smaller than 0.1mm, but tend to reach saturation values when the amplitude is larger. In a wide frequency range (0∼240Hz), the stiffness of the ERMR support shows gradual increasing trend with frequency, while the damping coefficient is approximately inversely proportional to frequency. The loss factor of the support displays nonmonotonic dependency on frequency and motion amplitude and distributes in 0.3–0.75. Based on the experimental investigation on the dynamic properties of the support, the dynamic tests on the rotor system with an ERMR support were conducted to obtain the dynamic behavior of the system. Under different imbalance exciting forces, the synchronous vibration responses were captured and the mechanical parameters were calculated. The results show that the critical speed remains nearly unchanged with the increase of the imbalance. The stiffness of the rotor system doesn’t exhibit strong nonlinearity, which is quite different from the traditional SFD. In wide rotating speed range, the loss factor of the rotor system distributes in 0.1–0.3, validating the remarkable damping capacity of the ERMR support.

Dielectric and structural properties of iron- and sodium-fumarates

2012 ◽  
Vol 36 (1) ◽  
pp. 21-29 ◽  
Author(s):  
Sonja Skuban ◽  
Tanja Džomié ◽  
Agneš Kapor ◽  
Željka Cvejić ◽  
Srđan Rakic
Keyword(s):  
Dielectric Constant ◽  
Ionic Conductivity ◽  
Structural Properties ◽  
Ac Conductivity ◽  
Loss Factor ◽  
Low Frequency ◽  
Relative Dielectric Constant ◽  
Frequency Range ◽  
Dielectric Parameters ◽  
Increasing Temperature

Abstract The behaviour of dielectric parameters such as the relative dielectric constant (ε''), the relative loss factor (ε'') and the ac conductivity of well known pharmaceutical materials Fe(II)-fumarate and Na-fumarate were studied as a function of temperature (in the range from 303K to 483 K) and frequency (in the range from 0.1 Hz to 100 kHz). The values of the conductivity are in the range of 10−5 Ω−1m−1 to 10−9 Ω−1m−1 for Fe(II)-fumarate and 10−6 Ω−1m−1 to 10−11 Ω−1m−1 for Na-fumarate. The conductivity of both materials increases with the increase in temperature and frequency. It was found that both ε' and ε'' decrease with increasing frequency and increase with increasing temperature for both materials. The highest changes are in the low frequency range. The obtained values of the dielectric parameters and conductivity suggest that these materials are dielectric with similar structure, most probably polymeric, with the mechanism of ionic conductivity.

scholarly journals Experimental study on the high-damping properties of metallic lattice structures obtained from SLM

2020 ◽  
Author(s):  
Federico Scalzo ◽  
Giovanni Totis ◽  
Emanuele Vaglio ◽  
Marco Sortino
Keyword(s):  
Dynamic Behaviour ◽  
Acoustic Noise ◽  
Lattice Structure ◽  
Low Frequency ◽  
Weight Ratio ◽  
Damping Capacity ◽  
Lattice Structures ◽  
Frequency Range ◽  
Global Dynamic ◽  
Manufacturing Technologies

Modern additive manufacturing technologies allow the creation of parts characterized by complex geometries that cannot be created using conventional production techniques. Among them the Selective Laser Melting (SLM) technique is very promising. By using SLM it is possible to create lightweight lattice structures that may fill void regions or partially replace bulk regions of a given mechanical component. As a consequence, the overall mechanical properties of the final component can be greatly enhanced, such as the resistance to weight ratio and its damping capacity against undesired vibrations or acoustic noise. Nevertheless, only a few research works focused on the characterization of the dynamic behaviour of lattice structures, that were mainly investigated in the low frequency range or directly tested on some specific applications. In this work the dynamic behaviour of lattice structures in the medium-high frequency range was experimentally investigated and then modelled. For this purpose, different types of lattice structures made of AlSi10Mg and AISI 316L were measured. Experimental modal analysis was performed on the obtained specimens in order to assess the influence of lattice material and unit cell geometry on their global dynamic behaviour. Experimental results revealed that lattice structures have superior damping characteristics compared to solid materials having an equivalent static stiffness. Eventually, the classic Rayleigh model was found to be adequate - with some approximation - to explain the damping behaviour of a generic lattice structure.

Experimental Study of Low-Frequency Effects on the Dynamic Modulus of a Buna-N Rubber

1955 ◽  
Vol 28 (1) ◽  
pp. 131-138 ◽  
Author(s):  
Allen Q. Hutton ◽  
A. W. Nolle
Keyword(s):  
Dynamic Modulus ◽  
Room Temperature ◽  
Temperature Scale ◽  
Dynamic Properties ◽  
Low Frequency ◽  
Frequency Range ◽  
Frequency Increase ◽  
Frequency Effects ◽  
Similar Compound ◽  
Linear Dynamic

Abstract The linear dynamic Young's modulus of a vulcanized Buna-N gum rubber was measured at frequencies of 0.05, 0.10, and 1.00 cps, in the temperature range − 22° C to 30° C, by a method in which a small differential sinusoidal elongation is superimposed on a 5 per cent static elongation. The width of the dispersion range on the temperature scale (the range in which the logarithm of the modulus increases steeply with decreasing temperature) is only about 10° C, contrasted with widths as great as 25° C found in previous measurements on a similar compound at frequencies of several kilocycles. The modulus-temperature plot shifts upward by only about 4° C per decade of frequency increase of the present range, contrasted with about 10° C per decade in the previous measurements at higher frequencies. It is concluded that this elastomer cannot be described properly by means of the “method of reduced variables”, in which the dynamic properties are ascribed to mechanisms having identical temperature dependence, and that the low-temperature behavior is governed by mechanisms distinct from those effective in the audio-frequency range at room temperature.

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