Amplitude dependence of the damping capacity for alloys of the Cu-Al-Zn-Cd system

1985 ◽  
Vol 17 (11) ◽  
pp. 1576-1578
Author(s):  
O. G. Zotov ◽  
S. Yu. Kondrat'ev ◽  
G. Ya. Yaroslavskii ◽  
B. S. Chaikovskii ◽  
V. V. Matveev
Keyword(s):  
Damping Capacity ◽  
Amplitude Dependence

Influence of Heat Treatment on Magnetic and Damping Properties of Fe-11 at.% Al Alloys

2008 ◽  
Vol 137 ◽  
pp. 129-136 ◽  
Author(s):  
Agnieszka Mielczarek ◽  
Werner Riehemann ◽  
Olga A. Sokolova ◽  
Igor S. Golovin
Keyword(s):  
Heat Treatment ◽  
Domain Walls ◽  
Magnetic Domain ◽  
Al Alloys ◽  
Damping Capacity ◽  
Amplitude Dependence ◽  
Magnetic Domain Walls ◽  
Mechanical Damping ◽  
The Difference ◽  
Vibrating Reed

The influence of heat treatment on the amplitude dependence of internal friction in Fe - 11 at. % Al alloys with carbon contents in the range 0.005 - 0.2 at. % has been studied using an inverted torsion pendulum in the temperature range 300 – 950 K and a vibrating reed apparatus at room temperature. The specimens were annealed at 1273 K in vacuum and cooled down with different cooling rates in order to obtain different degrees of order. It was found that ordering is hardly avoidable in Fe - Al alloys with Al contents > 11 at. %. Ordered alloys are characterised by lower damping capacity due to higher coercivity caused by additional pinning of magnetic domain walls by antiphase boundaries. X-ray diffraction investigations indicate that water-cooling suppresses ordering in Fe - 11 at. % Al alloys while cooling in air or in furnace provokes D03–type ordering. Slowly cooled specimens are characterised by higher damping capacity due to lower coercivity than water cooled or plastically deformed specimens. The amplitude dependent magneto-mechanical damping was determined as the difference between amplitude dependent damping without and with saturating magnetic field (~ 20 kA/m). Magneto-mechanical damping was found to be proportional to the strain where the amplitude dependent damping is maximum and reciprocal to the coercivity and saturation polarisation. Cold rolling increases the coercivity and therefore decreases the magneto-mechanical damping. An increase of the grain size in the investigated samples by heat treatment leads to a qualitatively expected decrease of coercivity and therefore to an increase of magneto-mechanical damping.

scholarly journals Strain Amplitude Dependence of High Damping Grp/Mg97Zn1Y2 Composites Ranging from Anelastic to Microplastic

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1570
Author(s):  
Diqing Wan ◽  
Shaoyun Dong ◽  
Yinglin Hu ◽  
Jiajun Hu ◽  
Yandan Xue ◽  
...  
Keyword(s):  
Particle Size ◽  
Strain Amplitude ◽  
Graphite Particle ◽  
Weak Interactions ◽  
Damping Capacity ◽  
Amplitude Dependence ◽  
Damping Properties ◽  
Microplastic Strain ◽  
Anelastic Strain ◽  
Transmission Electron

In this paper, the damping capacities and damping mechanisms of high damping, graphite-reinforced Mg97Zn1Y2 composites were investigated. Composites consisting of different graphite particle sizes (24, 11, and 3 μm) were designed and prepared using the casting method. The microstructure of the composites was examined using optical microscopy (OM) and transmission electron microscopy (TEM), which confirmed that the graphite particles were successfully planted into the Mg97Zn1Y2 matrix. Measurements made with a dynamic mechanical analyzer (DMA) showed that the Grp/Mg97Zn1Y2 composite has a high damping capacity. At the anelastic strain amplitude stage, the damping properties of the Grp/Mg97Zn1Y2 composites were found to be higher than those of the Mg97Zn1Y2 alloy. Furthermore, decreasing the graphite particle size was found to improve the damping properties of the Grp/Mg97Zn1Y2 composites. At the microplastic strain amplitude stage, the damping properties of the Mg97Zn1Y2 alloy were found to be higher than those of the Grp/Mg97Zn1Y2 composites. Moreover, the damping properties of the Grp/Mg97Zn1Y2 composites were found to decrease with increasing graphite particle size. The reason for the increased damping of the Grp/Mg97Zn1Y2 composites during the anelastic strain amplitude stage can be attributed to the increase in the number of damping sources and weak interactions among the dislocation damping mechanisms. At the microplastic strain amplitude stage, the damping properties of the composite are mainly affected by the activation volume of the slipped dislocation.

Strain Amplitude Dependence of Damping Capacity in High Damping Mg-Based Alloys Continuously Extending to Microplastic Strain

2010 ◽  
Vol 97-101 ◽  
pp. 937-940
Author(s):  
Di Qing Wan ◽  
Bo Lin He ◽  
Jin Cheng Wang ◽  
Gen Cang Yang
Keyword(s):  
Strain Amplitude ◽  
Low Frequency ◽  
Microplastic Deformation ◽  
Damping Capacity ◽  
Amplitude Dependence ◽  
Two Stage ◽  
Microplastic Strain ◽  
Damping Behavior ◽  
Dependent Part ◽  
Weakly Dependent

An investigation on low frequency strain amplitude dependence damping characteristic of as-cast high damping Mg-based alloys continuously extending to microplastic strain was carried out. Two-stage damping behavior via strain amplitude was particularly reported. The first is the strain amplitude strongly dependent part due to breakaway loss and the second is the strain amplitude weakly dependent part due to microplastic deformation loss, which is also frequency dependent. The damping mechanism is discussed in detail.

Effect of Deformation on the Damping Capacity of Magnesium Alloys

2005 ◽  
Vol 488-489 ◽  
pp. 737-740 ◽  
Author(s):  
Xiao Shi Hu ◽  
Kun Wu ◽  
Ming Yi Zheng ◽  
Shi Wei Xu ◽  
Y.K. Zhang
Keyword(s):  
Magnesium Alloy ◽  
Temperature Dependence ◽  
Magnesium Alloys ◽  
Room Temperature ◽  
Equal Channel Angular Extrusion ◽  
Damping Capacity ◽  
Amplitude Dependence ◽  
Az91d Alloy ◽  
Dynamic Mechanical Analyzer ◽  
Az91d Magnesium Alloy

Equal channel angular extrusion (ECAE) was applied to an as-cast AZ91D magnesium alloy. The strain amplitude dependence and temperature dependence of damping capacities of the as-cast and ECAE processed AZ91D alloys were investigated by dynamic mechanical analyzer (DMA). Microstructures of AZ91D alloys after ECAE were observed by optical microscopy (OM). In higher strain region, the damping value of 4-pass ECAE deformed AZ91D alloy was the highest among all the AZ91D alloys under different conditions. The damping peaks of ECAE deformed AZ91D alloys detected during heating from room temperature to 400°C were considered to be related to the migration of grain boundaries and the movement of dislocations during recrystallization.

Influence of Thermomechanical Treatment on the Damping Capacity of Selected Magnesium Alloys

2016 ◽  
Vol 879 ◽  
pp. 1992-1997
Author(s):  
Zuzanka Trojanová ◽  
Peter Palček ◽  
Mária Chalupová ◽  
Pavel Lukáč ◽  
Uwe Arlic
Keyword(s):  
Internal Friction ◽  
Magnesium Alloys ◽  
Significant Influence ◽  
Temperature Scale ◽  
Rolling Texture ◽  
Az31 Alloy ◽  
Dislocation Motion ◽  
Damping Capacity ◽  
Amplitude Dependence ◽  
Increasing Temperature

In the paper the temperature and amplitude dependence of internal friction in the AZ31, AZ63 and AZ91 alloys is reported. A rapid increase in internal friction with increasing temperature was estimated. Internal friction peaks were observed in AZ63 and AZ91 alloys. Position and height of the peaks in the temperature scale depends on the heating rate. Simultaneously, microstructural observations were performed in the selected points of the temperature scale. The amplitude dependence of internal friction in an AZ31 alloy, prepared by rolling, was measured. A significant influence of the rolling texture has been estimated. Main mechanisms of internal friction are connected with precipitation, dislocation motion and twinning.

Measurement and Analysis of Vibration Damping Capacity of Lotus-Type Porous Magnesium

2006 ◽  
Vol 512 ◽  
pp. 325-330
Author(s):  
Zhen Kai Xie ◽  
Soong Keun Hyun ◽  
Yosiyuki Okuda ◽  
Hideo Nakajima
Keyword(s):  
Vibration Damping ◽  
Unidirectional Solidification ◽  
Damping Capacity ◽  
Amplitude Dependence ◽  
Porous Metals ◽  
Fast Fourier Transform Analysis ◽  
Porous Copper ◽  
Measurement And Analysis ◽  
Porous Magnesium ◽  
Excitation Method

Lotus-type porous magnesium was fabricated by unidirectional solidification of the melt dissolving hydrogen in a high-pressure mixture gas of hydrogen and argon. The damping constant of porous magnesium with various porosities was measured by the hanging excitation method. The damping constant was defined as α=log (xn/xn+1)/T, where xn and xn+1 are the successive amplitude values of the damping wave, and T is the damping time. The frequency-amplitude dependence curve was obtained by Fast Fourier Transform analysis. The damping time of the lotus-type porous magnesium was observed to be shortened greatly compared with non-porous metals and porous copper. Moreover, the damping constant of the lotus-type porous magnesium was calculated by the damping amplitude.

Inducing Frictional Force to Enhance the Transient Response in Beams

2019 ◽  
Vol 22 (2) ◽  
pp. 88-93
Author(s):  
Hamed Khanger Mina ◽  
Waleed K. Al-Ashtrai
Keyword(s):  
Numerical Analysis ◽  
Transient Response ◽  
Frictional Force ◽  
Damping Ratio ◽  
Experimental Results ◽  
Damping Capacity ◽  
Tightening Force ◽  
Contact Areas ◽  
Good Agreement ◽  
Ansys Workbench

This paper studies the effect of contact areas on the transient response of mechanical structures. Precisely, it investigates replacing the ordinary beam of a structure by two beams of half the thickness, which are joined by bolts. The response of these beams is controlled by adjusting the tightening of the connecting bolts and hence changing the magnitude of the induced frictional force between the two beams which affect the beams damping capacity. A cantilever of two beams joined together by bolts has been investigated numerically and experimentally. The numerical analysis was performed using ANSYS-Workbench version 17.2. A good agreement between the numerical and experimental results has been obtained. In general, results showed that the two beams vibrate independently when the bolts were loosed and the structure stiffness is about 20 N/m and the damping ratio is about 0.008. With increasing the bolts tightening, the stiffness and the damping ratio of the structure were also increased till they reach their maximum values when the tightening force equals to 8330 N, where the structure now has stiffness equals to 88 N/m and the damping ratio is about 0.062. Beyond this force value, increasing the bolts tightening has no effect on stiffness of the structure while the damping ratio is decreased until it returned to 0.008 when the bolts tightening becomes immense and the beams behave as one beam of double thickness.

Sign in / Sign up

Export Citation Format

Share Document