The Evaluation of Rubber and Rubberlike Compositions as Vibration Absorbers. Apparatus for Automatic Recording

1937 ◽  
Vol 10 (4) ◽  
pp. 827-833
Author(s):  
Felix L. Yerzley
Keyword(s):  
Internal Friction ◽  
Dynamic Modulus ◽  
Automatic Recording ◽  
Vibration Absorbers ◽  
Dynamic Hardness ◽  
Static Hardness ◽  
Wide Range

Abstract The equipment is simple and foolproof. It provides an autographic record in a few seconds, from which can be evaluated dynamic hardness, dynamic modulus, internal friction, static hardness, and drift. It can be used to test rubber and rubberlike compositions over a very wide range of temperatures—for example, from −40° to 150° C. —for testing compositions which have been exposed to solvents or gases, and in conjunction with a fatigue machine for evaluation at various stages in a life flexing test.

Dynamic Properties of Rubber. Dependence on Pigment Loading

1941 ◽  
Vol 14 (4) ◽  
pp. 842-857 ◽  
Author(s):  
S. D. Gehman ◽  
D. E. Woodford ◽  
R. B. Stambaugh
Keyword(s):  
Zinc Oxide ◽  
Internal Friction ◽  
Dynamic Modulus ◽  
Dynamic Properties ◽  
Modulus Ratio ◽  
Volume Loading ◽  
Static Modulus ◽  
Black Clay ◽  
At Resonance ◽  
Wide Range

Abstract Dynamic properties are specific for different pigments. Curves show the dependence on pigment loading of the dynamic modulus, ratio of dynamic to static modulus, internal friction, dynamic resilience, and calculated relative heat generation at constant force and at constant amplitude. For the same volume loading, the dynamic modulus and internal friction rank in the order: Superspectra, channel black, zinc oxide, clay, blanc fixe, Thermatomic black, i.e., roughly in the order of particle size. The calculated dynamic resilience depends on the ratio of the modulus to the internal friction and increases in the order Superspectra, channel black, clay, Thermatomic black, blanc fixe, zinc oxide. The dynamic modulus shows an almost linear relation with the internal friction for different loadings of the same pigment. The dynamic modulus is independent of the frequency in the range 20–150 cycles per second. It depends on the amplitude, an effect which may be connected with the warming of the test-piece due to the vibration. The amplitude at resonance for the same driving force is approximately constant at all frequencies for a given rubber compound. The results show the wide range of dynamic properties obtainable with different pigments, and bring out the general principles involved in their use for dynamic purposes.

Dynamic Hardness of MCrAlY Abradable Seal Coating

2021 ◽  
Vol 1035 ◽  
pp. 591-595
Author(s):  
Dan Guo ◽  
Jian Ming Liu ◽  
De Ming Zhang ◽  
Xin Zhang ◽  
Tong Liu
Keyword(s):  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Hopkinson Pressure Bar ◽  
Dynamic Hardness ◽  
Mcraly Coating ◽  
Static Hardness ◽  
Split Hopkinson ◽  
The Difference ◽  
Pressure Bar ◽  
Abradable Coatings

The purpose of this investigation is to study the dynamic hardness of MCrAlY abradable coatings under different strain rates. A dynamic indentation device based on the split Hopkinson pressure bar system (SHPB) was used. The results show that the hardness of MCrAlY coating increased with the increase of the strain rate, which has a positive strain rate effect. In addition, the difference of the static hardness of MCrAlY coating prepared by HVOF and LPPS was only 4%, while the difference in dynamic hardness was 16%.

Internal friction and dynamic modulus of metaphosphate glass

2004 ◽  
Vol 337 (2) ◽  
pp. 187-190 ◽  
Author(s):  
M Sakamura ◽  
Y Kobayashi ◽  
M Ozawa ◽  
S Suzuki
Keyword(s):  
Internal Friction ◽  
Dynamic Modulus

Evaluation of Fatigue Life of Asphalt Concrete From Dynamic Modulus Test

2017 ◽  
Author(s):  
Md Mehedi Hasan ◽  
Hasan M. Faisal ◽  
Biswajit K. Bairgi ◽  
A. S. M. Rahman ◽  
Rafiqul Tarefder
Keyword(s):  
Fatigue Life ◽  
Asphalt Concrete ◽  
Dynamic Modulus ◽  
Performance Testing ◽  
Fatigue Performance ◽  
Construction Sites ◽  
Reclaimed Asphalt ◽  
Wide Range ◽  
Dynamic Modulus Test ◽  
Study Laboratory

Asphalt concrete’s dynamic modulus (|E*|) is one of the key input parameters for structural design of flexible pavement according to the Mechanistic Empirical Pavement Design Guide (MEPDG). Till this day, pavement industry uses |E*| to predict pavement performance whether the material is hot mix asphalt (HMA) or warm mx asphalt or Reclaimed Asphalt Pavement (RAP) mixed HMA. However, it is necessary to investigate the correlation of |E*| with laboratory performance testing. In this study, laboratory dynamic modulus test was conducted on four different asphalt concrete mixtures collected from different construction sites in the state of New Mexico and mastercurves were obtained to evaluate dynamic modulus (|E*|) for a wide range of frequency. In addition, fatigue performance of these mixtures was predicted from the mastercurves and compared with the laboratory fatigue performance testing. Fatigue performance of these mixtures was evaluated from the four point beam fatigue test. The laboratory results show a good agreement with the predicted value from mastercurves. It is also observed from this study that the fatigue life of the asphalt concrete materials decreases with increase in |E*| value.

Nonlinearity in the Dynamic Properties of Vulcanized Rubber Compounds

1954 ◽  
Vol 27 (1) ◽  
pp. 209-222 ◽  
Author(s):  
W. P. Fletcher ◽  
A. N. Gent
Keyword(s):  
Simple Shear ◽  
Dynamic Modulus ◽  
Dynamic Properties ◽  
Mechanical Vibration ◽  
Frequency Range ◽  
Vulcanized Rubber ◽  
Rubber Compounds ◽  
Chemical Combination ◽  
Wide Range ◽  
Static Shear

Abstract Measurements are described of the dynamic properties of rubber, loaded with various amounts and types of filler, when subjected to mechanical vibration in simple shear at amplitudes from 0 to 3 per cent shear in the frequency range 20 to 120 c.p.s. The decrease of dynamic modulus with increasing amplitude is shown, for a wide range of filler types and concentrations, to be determined by the amount of stiffening produced by the filler. This relationship is not influenced by variations in the vulcanizing ingredients, reasonable variations in state of vulcanization, addition of softener, or imposition of static shear strain. Rubber compounds stiffened by mixture with, or chemical combination of, other polymers exhibit a smaller order of nonlinearity than that described above and also exhibit much lower hysteresis values within the amplitude range 0 to 3 per cent shear.

Anelastic Behavior of Nanocrystalline Fe-Cr Alloy Obtained by Mechanical Alloying

2010 ◽  
Vol 146-147 ◽  
pp. 780-784
Author(s):  
Zheng Cun Zhou ◽  
J. Du ◽  
H. Yang
Keyword(s):  
Internal Friction ◽  
Mechanical Alloying ◽  
Dynamic Modulus ◽  
Room Temperature ◽  
Milling Time ◽  
Grain Sizes ◽  
Free Decay ◽  
Before And After ◽  
Anelastic Behavior ◽  
Increasing Temperature

Anelastic behavior of nanocrystalline Fe-17 wt.%Cr alloy obtained by mechanical alloying was investigated using a multifunctional internal friction apparatus. Internal friction (Q-1) and relative dynamic modulus (f2) have been measured as a function of temperature by free-decay method from room temperature to 400oC for the ball-milled Fe-17 wt.%Cr alloy The specimens with different milling time were examined by XRD to determine the solid solubility of Fe and Cr atoms and detect the lattice strain of the compacted specimen before and after annealing. TEM observation was employed to obtain further information about the morphology and microstructure, especially crystalline size, of the milled Fe and Cr mixture powders. It has been suggested that the anelastic behavior of ball-milled nanocrystalline Fe-17 wt.%Cr alloy origins from the viscoelastic sliding at the interfaces resulting from the thermally-activating process. The damping increasing of the specimen with smaller grain sizes is larger than that of the specimen with larger grain sizes with increasing temperature since the former contains more interfaces. The increase in the relative dynamic modulus is attributed to the structural reordering with the lowering of lattice micro-strain that is produced during milling when temperature is over 300oC.

Filler Network Change and Nonlinear Viscoelasticity of Rubbers

2006 ◽  
Vol 11-12 ◽  
pp. 729-732 ◽  
Author(s):  
Yoshinobu Isono ◽  
Y. Satoh ◽  
Shuji Fujii ◽  
Seiichi Kawahara ◽  
S. Kagami
Keyword(s):  
Electrical Resistivity ◽  
Dynamic Modulus ◽  
Network Formation ◽  
Nonlinear Viscoelasticity ◽  
Large Strain ◽  
Relaxation Modulus ◽  
Network Structures ◽  
Wide Range ◽  
Filled Rubbers ◽  
Filler Network

Uncured, filled rubbers show remarkable nonlinear viscoelasticity as well as cured, filled rubbers. The nonlinearity may come from change in entanglement and filler network structures. Many people use dynamic modulus to characterize rubber materials. However, dynamic modulus cannot be defined at large strain. Hence we must study a viscoelastic function to be defined at large strain. In addition, we need other information to separate the effects of the change in entanglement and filler network structures on nonlinear viscoelasticity. In this work, we have measured simultaneously relaxation modulus G(γ,t) and electrical resistivity ρ(γ,t) for carbon black (CB)-filled, uncured styrene-butadiene copolymers (SBRs) at wide range of strains. Electrical resistivity at equilibrium, ρ(0,t), showed step-like change at the CB loading between 20 and 35 phr, indicating threshold for filler network formation should exist in the range of values in CB loading. Both G(γ,t) and ρ(γ,t) for the samples having CB loading to be higher than the threshold showed nonlinearity at the strain larger than shear strain γ=0.1, indicating rupture in filler network at large strain.

Fatigue in Rubber. Part II

1939 ◽  
Vol 12 (2) ◽  
pp. 332-343 ◽  
Author(s):  
W. J. S. Naunton ◽  
J. R. S. Waring
Keyword(s):  
Carbon Black ◽  
Internal Friction ◽  
High Frequency ◽  
Strain Curve ◽  
Power Input ◽  
Viscous Resistance ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Wide Range ◽  
Rubber Part

Abstract 1. An apparatus is described for measuring the modulus and resilience of rubber over a wide range of frequencies. 2. These measurements can be made at any point in the stress-strain curve of the sample. 3. By increasing the power input, the same apparatus can be used to induce high frequency fatigue in the sample. 4. The earlier work with the torsion head apparatus has been confirmed, namely, that internal friction is greatest near zero strain. 5. High frequency resilience is more independent of degree of vulcanization than tripsometer resilience. 6. Modulus tends to increase with frequency. The effect is least with a rubber gum stock and is greater with compounds containing gas black. 7. Resilience decreases with frequency both in gum and gas black compounds. The decrease is more rapid in the gum compounds. 8. Viscous resistance decreases with frequency and becomes constant at higher frequencies. 9. The modulus of both rubber and Neoprene carbon black compounds decreases with fatigue. 10. The change in modulus with frequency in fatigued stocks is exactly analogous to the change before fatigue in rubber, but there is a slight divergence in the case of Neoprene.

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