Subject strain amplitude

Q(. and are experimentally determined from the cord and rubber samples by use of Allied High Strain Dynamic Vlscoelastometer ( 6 ) at various temperatures in the temperature range of room temperature - 160 deg. C and under various strain amplitudes. The resulting data are subjected to regression analysis to store the data in a computer-retrievable form. Thus, by giving T and e for cord or rubber, Q. and can be produced for the sample In the computation. 

The same specimen was subjected to a cyclic tension-compression mode with 0.1% constant strain amplitude. Curves (e) and (f) in Fig. 2 are the data after 500 and 1000 cycles, respectively. After 1000 cycles, the resistivity started to saturate. The increase in resistivity after 1000 cycles is about 70% of the value of curve (d) in the field range of 1 to 5 T. After 4 days of annealing at 300 K, about 75% of the resistivity increase due to the cyclic strain was annealed out, curve (g). This means that the permanent increase in resistivity was only about 18% of the value of curve (d). This is probably due to dislocations. 

In Table 3 the effect of nominal strain amplitude (a/h) was evaluated. In the runs reported in the first half of Table 3, sample 1 (run against SE-30) was subjected to amplitudes from 0.52 to 5.,09 percent while the second half lists results for sample 3 and higher amplitudes (2.66-7.7%). 

Permanent structural changes that occur in a material subjected to fluctuating stress and strain, which cause decay of mechanical properties. See S-N diagram. The ability of a material to plastically deform before fracturing in constant strain amplitude and low-cycle fatigue tests. See S-N diagram. ... 

Several rheometers do not subject the polymer to a steady rate of deformation but to an oscillatory deformation, usually sinusoidal simple shear. If the angular frequency is o, and the shear strain amplitude Yo. the shear strain y can be written as a function of time ... 

The viscoelastic properties of concentrated o/w and w/o emulsions were investigated using dynamic (oscillatory) measurements. For that purpose a Bohlin VOR (Bohlin Reologie, Lund, Sweden) instrument was used. Concentric cylinder platens were used and the measurements were carried out at 25 0.1 °C. In oscillatory measurements, the response in stress of a viscoelastic material subjected to a sinusoidally varying strain is monitored as a function of strain amplitude and frequency. The stress amplitude is also a sinusoidally varying function in time, but for a viscoelastic material it is shifted out of phase with the strain. The phase angle shift between stress and strain, 5, is given by... 

Fig. 3.5 Detail of an orange peel surface observed by Milella on a specimen of austenitic stainless steel subjected to a 15 % total strain amplitude. Note slip lines intersecting at 120°...

Fig. 6.11 Progressive reduction of mean stress and hysteresis loop in a smooth specimen of A 106B carbon steel subjected to low cycle fatigue at 288 °C. a strain amplitude = 0.74 % and b = 0.19 % [16]...

When the steel material is subjected to constant strain amplitude under cyclic loading, it exhibits a response that converges to a stabilized saturation loop which depends only on the cycling amplitude (Fig. 7b). As it is shown in Fig. 8, the response of the steel material under... 

Nonlinear properties of normal dielectrics can be studied in the elastic regime by the method of shock compression in much the same way nonlinear piezoelectric properties have been studied. In the earlier analysis it was shown that the shape of the current pulse delivered to a short circuit by a shock-compressed piezoelectric disk was influenced by strain-induced changes in permittivity. When a normal dielectric disk is biased by an electric field and is subjected to shock compression, a current pulse is also delivered into an external circuit. In the short-circuit approximation, the amplitude of this current pulse provides a direct measure of the shock-induced change in permittivity of the dielectric. 

Cyclic fatigue measurements require the specimen to be subjected to cyclic stress or strain of a higher amplitude than that employed for the simple dynamic test just described. The deformation must be of sufficient intensity to bring about specimen failure after a certain number of cycles, N. The value of stress leading to failure for a given N is typically 20% to 40% of the static tensile strength. 

Kevlar aramid fiber has good vibration damping characteristics. Dynamic (commonly sinusoidal) perturbations are used to study the damping behavior of a material. The material is subjected to an oscillatory strain. We can characterize the damping behavior in terms of a quantity called the logarithmic decrement, A, which is defined as the natural logarithm of the ratio of amplitudes of successive vibrations, i.e. 

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