scholarly journals A simple torsion pendulum for measuring internal friction

JOM ◽  
1950 ◽  
Vol 2 (11) ◽  
pp. 1322-1322
Author(s):  
M. E. Fine
Keyword(s):  
Internal Friction ◽  
Torsion Pendulum

On the Internal Friction of Ti50Ni25Cu25 Particle/Al Smart Composite

2005 ◽  
Vol 475-479 ◽  
pp. 2051-2054
Author(s):  
P. Shi ◽  
Li Shan Cui ◽  
Da Zhi Yang
Keyword(s):  
Internal Friction ◽  
Vibration Amplitude ◽  
Bulk Material ◽  
Damping Capacity ◽  
Torsion Pendulum ◽  
Smart Composite ◽  
Friction Behavior ◽  
Thermal Expansion Coefficients ◽  
Al Composite ◽  
Expansion Coefficients

The Ti50Ni25Cu25 particle/Al composite was fabricated with 30 vol.% Ti50Ni25Cu25 particles by hot pressing and followed by extruding methods. The internal friction (IF) measurements of the composite were carried out on an inverted torsion pendulum. Ti50Ni25Cu25 particles embedded in Al matrix improve the damping capacity of the composite. The internal friction behavior of Ti50Ni25Cu25 particles is consistent to that of the Ti50Ni25Cu25 bulk material. The mismatch of thermal expansion coefficients between Ti50Ni25Cu25 and Al contributes to the damping capacity of the composite. A high damping capacity of the composite could be obtained at low vibration frequency and large vibration amplitude.

N--H Interaction in Nitrided Fe--Nb Alloys

2007 ◽  
Vol 539-543 ◽  
pp. 4987-4992
Author(s):  
Masatoshi Sakamoto
Keyword(s):  
Internal Friction ◽  
Room Temperature ◽  
Diffusion Rate ◽  
Interstitial Site ◽  
Torsion Pendulum ◽  
Nitriding Temperature ◽  
Octahedral Interstitial Site ◽  
Snoek Peak ◽  
Strong Affinity ◽  
Temperature Side

Internal friction of nitrogen in α iron has known as Snoek peak of N atom resolv ed in the octahedral interstitial site of bcc. When M atom ( Mn, Mo, Si, et.al) which has the affinity bigger than Fe were added ,another peaks due to the jump of N from Fe-Fe site to Fe-M site appear in the upper temperature side and complicate the Snoek peak curve of N. In this paper, the Snoek peak curve was studied in Fe-0.4wt%Nb-0.02wt%N alloys. This alloy showed no other peaks in the upper side to 373K and had only the single peak of N in Fe-Fe site. Internal friction measured by torsion pendulum method at about 1 Hz. After that this alloy was cooled from 373K to room temperature and reheated to 373K, but Snoek peak of N which showed on the first measurement just after nitriding disappeared completely and internal friction was only background. One of the reasons of it is the precipitation of Fe16N2 under heating and resolved N atoms disappeared. So these specimens were reheated to 873K and quenched, but Snoek peak of N was not measured. This shows the disappearance of N atom from Fe-Fe site. The mixture gas of a few % NH3 and H2 was used in this study. Therefore after nitriding much of H atoms were resolved in α iron alloys. Because the diffusion rate of H atom in α iron is bigger than N atom , it expected that H atoms can combine with Nb atoms before coming N atoms. And the appearance of Snoek peak of N in these alloys is considered. After that, in the heating to 373K H atom leave Nb and go away from the surface, and N atoms combine with Nb in place of H atoms. Nb has the very strong affinity with N, so these alloys have no peaks. When they reheated to the nitriding temperature N atoms can not diffuse from Fe-Nb site to Fe-Fe site. Then Snoek peak of N can not appears again in these alloys. Therefore, when Fe-Nb alloys were nitrided in NH3 and H2 mixture gas H atom plays very important part and it needs that the interaction of N-H atoms will be considered in these nitrided Fe-Nb alloys.

Automation of internal friction measurement apparatus of inverted torsion pendulum type

1981 ◽  
Vol 14 (10) ◽  
pp. 1201-1206 ◽  
Author(s):  
I Yoshida ◽  
T Sugai ◽  
S Tani ◽  
M Motegi ◽  
K Minamida ◽  
...  
Keyword(s):  
Internal Friction ◽  
Torsion Pendulum ◽  
Friction Measurement ◽  
Measurement Apparatus ◽  
Internal Friction Measurement

scholarly journals A New Inverted Torsion Pendulum-Based Mechanical Spectrometer to Study Soft Matter

2016 ◽  
Vol 61 (1) ◽  
pp. 13-16 ◽  
Author(s):  
M.L. Lei ◽  
L. Chen ◽  
X.M. Xiong
Keyword(s):  
Internal Friction ◽  
High Precision ◽  
Soft Matter ◽  
Wide Frequency Range ◽  
The Novel ◽  
Torsion Pendulum ◽  
Frequency Range ◽  
Basic Principles

A new multifunctional mechanical spectrometer is developed based on an inverted torsion pendulum showing high precision in a wide frequency range to study soft matter. Apart from measuring the internal friction of solids it can also be used to study viscoelasticity. In this report we describe basic principles of the novel instrument.

scholarly journals Internal Friction on AISI 304 Stainless Steels with Low Tensile Deformations at Temperatures between−50 and 20C

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
T. F. A. Santos ◽  
M. S. Andrade
Keyword(s):  
Internal Friction ◽  
Stainless Steels ◽  
True Strain ◽  
Austenitic Stainless Steels ◽  
Torsion Pendulum ◽  
Internal Friction Peak ◽  
Aisi 304 ◽  
Degree Of Deformation ◽  
Hexagonal Close Packed ◽  
Damping Behavior

Austenitic stainless steels specimens were deformed by tension in temperatures in the range of−50Cto 20Cand 0.03 to 0.12 true strain, in order to obtain different volumetric fractions ofε(hexagonal close packed) andα′(body centered cubic) strain induced martensites. The morphology, distribution and volumetric fractions of the martensites were characterized by metallography and dilatometry analysis and quantified by ferrite detector measurements. The damping behavior of specimens with different volumetric fractions of martensites was studied in an inverted torsion pendulum in the 40Cto 400Crange. Theε- andα′-martensites reversion was observed in the temperature range of 50C–200Cand 500C–800C, respectively, by dilatometry. Internal friction curves in function of temperature of the deformed samples presented internal friction peaks. The first internal friction peak is related to sum of the amount ofε- andα′-martensites. For low deformations it aligns around 130Cand it is related only to theε→γreverse transformation. The peak situated around 350Cincreases with the specimen degree of deformation and is, probably, related to the presence ofα′/γinterfaces, and deformed austenite.

Torsion pendulum method to evaluate the internal friction and elastic modulus of films

2003 ◽  
Vol 74 (4) ◽  
pp. 2477-2480 ◽  
Author(s):  
Z. S. Li ◽  
Q. F. Fang ◽  
S. Veprek ◽  
S. Z. Li
Keyword(s):  
Elastic Modulus ◽  
Internal Friction ◽  
Torsion Pendulum
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