Hysteresis in Crystallization of Stretched Vulcanized Rubber from X-Ray Data. Correlation with Stress-Strain Behavior and Resilience

1941 ◽  
Vol 14 (1) ◽  
pp. 27-34
Author(s):  
George L. Clark ◽  
Marian Kabler ◽  
Ernest Blaker ◽  
John M. Ball
Keyword(s):  
Normal State ◽  
Previous History ◽  
The Body ◽  
Stress Strain ◽  
X Ray ◽  
Strain Behavior ◽  
Vulcanized Rubber ◽  
Set Up ◽  
Applied Stresses ◽  
Marked Tendency

Abstract 1. For sample H, with high modulus and high resilience, there is a greater crystallizing tendency above 350 per cent for the first cycle and above 400 per cent after previous flexing. 2. Both H and L have narrow loops, which indicate an approach to reversibility in the formation and deformation of crystalline regions above 400 per cent for the first and later cycles. 3. The crystallization of H is greatly enhanced above 400 per cent after the first cycle of stretching and retraction; L remains essentially unchanged by previous history over this range; this is analogous to the much greater change in the stress-strain loop from the first to third cycles for H, as compared with L. 4. At elongations below 400 per cent for the first cycle and 350 per cent for subsequent cycles, L has a far greater hysteresis or tendency to retain the crystalline arrangement, and this greatly increases after the first cycle, so that the fiber interferences persist on retraction to elongations 150 per cent below the elongation required for institution of organization on extension of the sample. Sample H is considerably more consistent in its behavior over the lower elongations, and between the first and later cycles. In other words, the tendency of H to return to the normal state on release of a deforming force is clearly evident, whereas L shows a marked tendency to retain a structure once set up. If resilience is the property of an elastic body related to the percentage of the potential energy introduced by applied stresses which is returned as work when the body returns to its original shape and size upon release of the stresses, then these x-ray data would seem to be consistent with the higher resilience of H; for ordinary measurements of resilience are evidently related to the lower ranges of deformation over which H returns to its normal state (disorder of macromolecules as in a liquid) so much more easily than L.

scholarly journals Evaluation of stress-strain behavior of surface treated steels by X-ray diffraction

2012 ◽  
Vol 2 (1) ◽  
Author(s):  
Luis Coelho ◽  
A. Batista ◽  
J. Nobre ◽  
M. Marques
Keyword(s):  
Yield Strength ◽  
Plasma Nitriding ◽  
Nitrided Layer ◽  
Experimental Methodology ◽  
X Ray Diffraction ◽  
Stress Strain ◽  
X Ray ◽  
Strain Behavior ◽  
Four Point Bending ◽  
Nitride Layers

AbstractX-ray diffraction assisted four-point bending method (XRDABM) enables to analyze the evolution of surface stress with the strain during bending of specimens. This experimental methodology was used to characterize the stress-strain behavior of two plasma nitriding steels, DIN 40 Cr Mn Mo 7 and DIN 32 Cr Mo V 13, with gradients of mechanical properties across the surface layers, allowing the characterization of the in-depth evolution of the local yield strength in the nitrided layer. The results show a significantly increase of the yield strength of the nitride layers and a good agreement between the in-depth evolution of the yield strength and the XRD peak breadth for the two nitrided steels.

A Study into the Behavior of an Aluminum Foam under Compression

2013 ◽  
Vol 535-536 ◽  
pp. 64-67
Author(s):  
C. Mahesh ◽  
Anindya Deb ◽  
S.V. Kailas ◽  
C. Uma Shankar ◽  
T.R.G. Kutty ◽  
...  
Keyword(s):  
Aluminum Foam ◽  
Absorption Capacity ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Stress Strain ◽  
Compression Loading ◽  
Strain Behavior ◽  
Axial Crush ◽  
Set Up ◽  
Energy Absorbing

The characterization of a closed-cell aluminum foam with the trade name Alporas is carried out here under compression loading for a nominal cross-head speed of 1 mm/min. Foam samples in the form of cubes are tested in a UTM and the average stress-strain behavior is obtained which clearly displays a plateau strength of approximately 2 MPa. It is noted that the specific energy absorption capacity of the foam can be high despite its low strength which makes it attractive as a material for certain energy-absorbing countermeasures. The mechanical behavior of the present Alporas foam is simulated using cellular (i.e. so-called microstructure-based) and solid element-based finite element models. The efficacy of the cellular approach is shown, perhaps for the first time in published literature, in terms of prediction of both stress-strain response and inclined fold formation during axial crush under compression loading. Keeping in mind future applications under impact loads, limited results are presented when foam samples are subjected to low velocity impact in a drop-weight test set-up.

Stress-Strain Behavior of Hot-Compression Mg-Li Alloy

2012 ◽  
Vol 485 ◽  
pp. 283-287
Author(s):  
Jian Bo Wen ◽  
Qian Liu ◽  
Deng Yu Gai
Keyword(s):  
Regression Analysis ◽  
Flow Stress ◽  
Hot Compression ◽  
Compression Process ◽  
Stress Strain ◽  
Arithmetic Average ◽  
Strain Behavior ◽  
Set Up ◽  
Gleeble 3500 ◽  
Gleeble 3500 System

The stress-strain behavior of hot-compression Mg-Li alloy was investigated by using a physical simulator Gleeble-3500 system. And the constitutive equation was set up by regression analysis and BP neural networks. Results show that the dynamic recrystallization occured during the hot-compression process. The grain size of the alloy increased and the stress decreased with increasing temperature. Regression analysis indicates that the flow stress can be expressed by hyperbolic sine model and the arithmetic average of errors is 14.13%. Training the flow stress prediction model with MatLab by an improved BP，the maximum arithmetic average of errors is 4.27%. The predicted stress-strain curves are in good agreement with the experimental results.

X-Ray Investigation of the Crystallization of Vulcanized Rubber on Stretching

1948 ◽  
Vol 21 (3) ◽  
pp. 621-626 ◽  
Author(s):  
B. V. Lukin ◽  
V. I. Kasatochkin
Keyword(s):  
Tensile Strength ◽  
Crystalline Phase ◽  
Oxidative Degradation ◽  
Point Of View ◽  
Crystal Formation ◽  
Stress Strain ◽  
X Ray ◽  
Vulcanized Rubber ◽  
Cross Links ◽  
Ray Methods

Abstract 1. x-Ray methods have been used to investigate the amount of crystalline phase in stretched samples as a function of the vulcanization time. 2. Curves relating the percentage of crystalline phase to the vulcanization time have sharply defined maxima. 3. A comparison of the curves relating tensile strength to vulcanization time with the curves of crystal formation shows their analogous character, the position of the maxima approximately corresponding to one and the same vulcanization time. 4. The position of the maxima on the curves of crystal formation is not related to the degree of stretching. 5. The effect of accelerators is to shift the maximum on the curve of crystal formation to the region of short vulcanization times and to increase the percentage of crystalline phase. 6. The curves of crystal formation and of tensile strength, and thus the behavior of the stress-strain curves for various vulcanization times, is interpreted from the point of view of the existence of two processes—the process of forming a network of cross-links by the interaction of rubber with sulfur, and the process of oxidative degradation of the rubber.

X-Ray Studies of Preferred Orientations and Stress-Strain Relations in Rapidly Deformed Copper

1961 ◽  
Vol 5 ◽  
pp. 161-168
Author(s):  
M.K. Gainer ◽  
C.M. Glass
Keyword(s):  
Grain Orientation ◽  
Plastic Region ◽  
X Ray Diffraction ◽  
Large Specimen ◽  
Stress Strain ◽  
Orientation Analysis ◽  
X Ray ◽  
Strain Relationship ◽  
Applied Stresses

AbstractA stress-strain relationship for copper in the plastic region has been determined by examining the influence of the applied stresses on the grain orientation of shear-formed specimens. Instrumentation was developed to permit accurate grain-orientation analysis of a large specimen by X-ray diffraction without the necessity for deformation or destruction of the specimen.

Evaluation of Freezing Methods by Low Temperature X-Ray Diffraction

1977 ◽  
Vol 35 ◽  
pp. 330-333
Author(s):  
T. Gulik-Krzywicki ◽  
M.J. Costello
Keyword(s):  
Biological Materials ◽  
Molecular Organization ◽  
X Ray Diffraction ◽  
Glass Capillary ◽  
X Ray ◽  
Rate Dependent ◽  
Before And After ◽  
Freeze Etching ◽  
Diffraction Patterns ◽  
Set Up

Freeze-etching electron microscopy is currently one of the best methods for studying molecular organization of biological materials. Its application, however, is still limited by our imprecise knowledge about the perturbations of the original organization which may occur during quenching and fracturing of the samples and during the replication of fractured surfaces. Although it is well known that the preservation of the molecular organization of biological materials is critically dependent on the rate of freezing of the samples, little information is presently available concerning the nature and the extent of freezing-rate dependent perturbations of the original organizations. In order to obtain this information, we have developed a method based on the comparison of x-ray diffraction patterns of samples before and after freezing, prior to fracturing and replication.Our experimental set-up is shown in Fig. 1. The sample to be quenched is placed on its holder which is then mounted on a small metal holder (O) fixed on a glass capillary (p), whose position is controlled by a micromanipulator.

X-ray micro tomography in the scanning electron microscope

1978 ◽  
Vol 36 (1) ◽  
pp. 106-107 ◽  
Author(s):  
W. Brünger
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Target Surface ◽  
The Body ◽  
X Rays ◽  
Cross Sectional ◽  
X Ray ◽  
Micro Tomography ◽  
Scanning Electron

Reconstructive tomography is a new technique in diagnostic radiology for imaging cross-sectional planes of the human body /1/. A collimated beam of X-rays is scanned through a thin slice of the body and the transmitted intensity is recorded by a detector giving a linear shadow graph or projection (see fig. 1). Many of these projections at different angles are used to reconstruct the body-layer, usually with the aid of a computer. The picture element size of present tomographic scanners is approximately 1.1 mm2.Micro tomography can be realized using the very fine X-ray source generated by the focused electron beam of a scanning electron microscope (see fig. 2). The translation of the X-ray source is done by a line scan of the electron beam on a polished target surface /2/. Projections at different angles are produced by rotating the object.During the registration of a single scan the electron beam is deflected in one direction only, while both deflections are operating in the display tube.

Great Increase of Numbers of Virus Particles by Irradiating C3H Mouse Mammary Tumors Transplanted into Male Mice

1972 ◽  
Vol 30 ◽  
pp. 272-273
Author(s):  
P. J. Melnick ◽  
J. W. Cha ◽  
E. Samouhos
Keyword(s):  
Subcutaneous Tissue ◽  
Mammary Tumors ◽  
The Body ◽  
X Ray ◽  
Virus Particles ◽  
Mouse Mammary Tumors ◽  
Transplantable Tumors ◽  
C3h Mice ◽  
Cobalt Radiation ◽  
Enzyme Changes

Spontaneous mammary tumors in females of a high tumor strain of C3H mice were cut into small fragments that were Implanted into the subcutaneous tissue of the back of males of the same strain, where they grew as transplantable tumors. When about Cm. In diameter daily fractional radiation was begun, applied to the tumors, the rest of the body being shielded by a lead shield. Two groups were treated with 150 and 200 r X-ray dally, of half value layer 0.6mm. copper; a third group was treated with 500 r cobalt radiation dally. The primary purpose was to examine the enzyme changes during radiation, with histochemlcal technics.

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