Method for obtaining the spectrum of plastic strains of mesoscopic volume elements in fatigued materials investigated by X-rays. I. plastic and elastic strains in fatigued material

1984 ◽  
Vol 82 (1) ◽  
pp. 75-84 ◽  
Author(s):  
G. K. Schmidt
Keyword(s):  
Plastic Strains ◽  
X Rays ◽  
Elastic Strains

A New Model for Accelerated Thermal Cycle Testing With Application to TAB Leads and PCB PTHs

1994 ◽  
Vol 116 (1) ◽  
pp. 16-22 ◽  
Author(s):  
R. G. Bayer
Keyword(s):  
Plastic Strain ◽  
Thermal Cycle ◽  
The Other ◽  
Plastic Strains ◽  
Proposed Model ◽  
Goodman Diagram ◽  
Accelerated Thermal Cycling ◽  
Mean Strain ◽  
Elastic Strains ◽  
Good Agreement

A model for thermal fatigue that accounts for both plastic and elastic strains and a mean strain is developed. The model is based on a combination of the generalized Coffin-Manson Equation and the Goodman diagram for fatigue. This model was applied to two accelerated thermal cycling tests—one was for TAB leads; the other, unfilled PTHs at TCM sites in PC boards. Good agreement between the model and data was found. In addition, an existing industry model, which is based solely on plastic strain, is compared to the proposed model and the observed behavior in these two tests. It was concluded that both the effects of elastic and plastic strains and a mean strain are needed to explain the results of these evaluations.

Residual Microstress of Austenitic Stainless Steel Due to Tensile Deformation

2010 ◽  
Vol 652 ◽  
pp. 7-12 ◽  
Author(s):  
Kenji Suzuki ◽  
Takahisa Shobu
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Plastic Strain ◽  
Tensile Deformation ◽  
Annealed Specimen ◽  
Plastic Strains ◽  
X Rays ◽  
Lattice Plane ◽  
Coarse Grains

Material of the specimen was austenitic stainless steel (SUS316L). The specimens were given tensile plastic strains from 0% to 55%. The Vickers hardness of the specimen corresponded to the plastic strain. The residual macrostress was measured by Mn-Kα radiations. The residual macrostress of the annealed specimen had a small compression and changed into a tension after ten- sile plastic deformation. The specimen with 1% plastic strain showed the maximum tensile residual stress. To examine the dependency of the residual stress on the lattice plane, the residual microstress for each lattice plane was measured by hard synchrotron X-rays. The residual microstress was related with Young’s modulus which was calculated by Kro¨ ner model. A new method, 2θ-cos2 χ method, was proposed to solve the problem of coarse grains and it was excellent in comparison with the sin2 ψ method.

Plastic Deformations of a Free Ring Under Concentrated Dynamic Loading

1955 ◽  
Vol 22 (4) ◽  
pp. 523-529
Author(s):  
R. H. Owens ◽  
P. S. Symonds
Keyword(s):  
Dynamic Loading ◽  
Arbitrary Shape ◽  
Time Dependent ◽  
Plastic Behavior ◽  
Plastic Strains ◽  
Plastic Deformations ◽  
Free Ring ◽  
Thin Ring ◽  
Special Case ◽  
Elastic Strains

Abstract A concentrated time-dependent force acts on an unsupported thin ring along a diameter. The problem considered in this paper is to determine the deformations of the ring when the force magnitudes are such that plastic strains large compared with elastic strains occur. By neglecting elastic strains and assuming ideally plastic behavior, approximations to the final deformations of the ring are obtained. The analysis is developed for force pulses of arbitrary shape, but numerical results are obtained only in the special case of a rectangular force pulse. A criterion is stated for conditions when this type of analysis can be expected to provide satisfactory results.

Metal Microstructures in Four Dimensions

2004 ◽  
Author(s):  
S. F. Nielsen ◽  
C. Gundlach ◽  
E. M. Lauridsen ◽  
R. V. Martins ◽  
H. F. Poulsen ◽  
...  
Keyword(s):  
Grain Growth ◽  
Three Dimensional ◽  
High Energy ◽  
Third Generation ◽  
Plastic Strains ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Four Dimensions

By Three Dimensional X-ray Diffraction (3DXRD) microscopy it is possible to characterize microstructures non-destructively in 3 dimensions. The measurements are furthermore typically so fast that dynamics may be monitored in-situ, giving also the 4th dimension, namely the time. The 3DXRD technique is based on diffraction of high energy x-rays from third generation synchrotron sources. In the present paper the 3DXRD technique is described and it’s potentials are illustrated by examples relating to elastic and plastic strains, recovery, recrystallization and grain growth.

Plastic-Elastic strains in two-dimensional sections of partial-penetration fillet welds

1989 ◽  
Vol 24 (1) ◽  
pp. 15-21 ◽  
Author(s):  
H Fessler ◽  
C Pappalettere
Keyword(s):  
Heat Affected Zone ◽  
Fillet Welds ◽  
Plastic Collapse ◽  
Plastic Strains ◽  
Weld Toes ◽  
Two Dimensional ◽  
Pure Bending ◽  
Coating Technique ◽  
Plate Models ◽  
Elastic Strains

The photoelastic coating technique was used to study plastic strains at the orthogonal intersections of plates, formed by welding two side plates, without weld preparation, to a main plate. Models were cut from this weldment, perpendicularly to the planes of the plates. These models were loaded by tension and pure bending applied to the side plates. Although yielding starts at the weld toes, it remains constrained there due to the greater strength of the heat-affected zone. Plastic collapse occurs in the ‘parent’ plate. This phenomenon is due to the heat affected zone, not due to the notch formed by the weld.

White-Light Coronal Structures: Streamers and CMEs

1994 ◽  
Vol 144 ◽  
pp. 82
Author(s):  
E. Hildner
Keyword(s):  
Emission Line ◽  
Electron Density ◽  
White Light ◽  
Coronal Mass Ejections ◽  
X Rays ◽  
Solar Cycles ◽  
Temperature Function ◽  
X Ray ◽  
Eclipse Observations ◽  
Coronal Structures

AbstractOver the last twenty years, orbiting coronagraphs have vastly increased the amount of observational material for the whitelight corona. Spanning almost two solar cycles, and augmented by ground-based K-coronameter, emission-line, and eclipse observations, these data allow us to assess,inter alia: the typical and atypical behavior of the corona; how the corona evolves on time scales from minutes to a decade; and (in some respects) the relation between photospheric, coronal, and interplanetary features. This talk will review recent results on these three topics. A remark or two will attempt to relate the whitelight corona between 1.5 and 6 R⊙to the corona seen at lower altitudes in soft X-rays (e.g., with Yohkoh). The whitelight emission depends only on integrated electron density independent of temperature, whereas the soft X-ray emission depends upon the integral of electron density squared times a temperature function. The properties of coronal mass ejections (CMEs) will be reviewed briefly and their relationships to other solar and interplanetary phenomena will be noted.

Emergence of Twisted Magnetic Flux Related Sigmoidal Brightening

2000 ◽  
Vol 179 ◽  
pp. 263-264
Author(s):  
K. Sundara Raman ◽  
K. B. Ramesh ◽  
R. Selvendran ◽  
P. S. M. Aleem ◽  
K. M. Hiremath
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Magnetic Flux ◽  
Ultra Violet ◽  
Active Regions ◽  
Morphological Properties ◽  
Energy Storage And Conversion ◽  
The Sun ◽  
X Rays ◽  
The Magnetic Field

Extended AbstractWe have examined the morphological properties of a sigmoid associated with an SXR (soft X-ray) flare. The sigmoid is cospatial with the EUV (extreme ultra violet) images and in the optical part lies along an S-shaped Hαfilament. The photoheliogram shows flux emergence within an existingδtype sunspot which has caused the rotation of the umbrae giving rise to the sigmoidal brightening.It is now widely accepted that flares derive their energy from the magnetic fields of the active regions and coronal levels are considered to be the flare sites. But still a satisfactory understanding of the flare processes has not been achieved because of the difficulties encountered to predict and estimate the probability of flare eruptions. The convection flows and vortices below the photosphere transport and concentrate magnetic field, which subsequently appear as active regions in the photosphere (Rust & Kumar 1994 and the references therein). Successive emergence of magnetic flux, twist the field, creating flare productive magnetic shear and has been studied by many authors (Sundara Ramanet al.1998 and the references therein). Hence, it is considered that the flare is powered by the energy stored in the twisted magnetic flux tubes (Kurokawa 1996 and the references therein). Rust & Kumar (1996) named the S-shaped bright coronal loops that appear in soft X-rays as ‘Sigmoids’ and concluded that this S-shaped distortion is due to the twist developed in the magnetic field lines. These transient sigmoidal features tell a great deal about unstable coronal magnetic fields, as these regions are more likely to be eruptive (Canfieldet al.1999). As the magnetic fields of the active regions are deep rooted in the Sun, the twist developed in the subphotospheric flux tube penetrates the photosphere and extends in to the corona. Thus, it is essentially favourable for the subphotospheric twist to unwind the twist and transmit it through the photosphere to the corona. Therefore, it becomes essential to make complete observational descriptions of a flare from the magnetic field changes that are taking place in different atmospheric levels of the Sun, to pin down the energy storage and conversion process that trigger the flare phenomena.

The Clinical, Roentgenological and Morphological Effects of an Acute Exposure of Phosgene on the Lungs of Dogs

1971 ◽  
Vol 29 ◽  
pp. 236-237
Author(s):  
R. F. Bils ◽  
W. F. Diller ◽  
F. Huth
Keyword(s):  
Latent Period ◽  
Chemical Industry ◽  
Toxic Substance ◽  
Lung Edema ◽  
X Rays ◽  
Beagle Dogs ◽  
Male And Female ◽  
Morphological Alterations ◽  
Before And After ◽  
Electron Microscopes

Phosgene still plays an important role as a toxic substance in the chemical industry. Thiess (1968) recently reported observations on numerous cases of phosgene poisoning. A serious difficulty in the clinical handling of phosgene poisoning cases is a relatively long latent period, up to 12 hours, with no obvious signs of severity. At about 12 hours heavy lung edema appears suddenly, however changes can be seen in routine X-rays taken after only a few hours' exposure (Diller et al., 1969). This study was undertaken to correlate these early changes seen by the roengenologist with morphological alterations in the lungs seen in the'light and electron microscopes.Forty-two adult male and female Beagle dogs were selected for these exposure experiments. Treated animals were exposed to 94.5-107-5 ppm phosgene for 10 min. in a 15 m3 chamber. Roentgenograms were made of the thorax of each animal before and after exposure, up to 24 hrs.

Chemical Species Identification in an SEM by Changes in Emitted X-Ray Energies

1974 ◽  
Vol 32 ◽  
pp. 570-571
Author(s):  
R. H. Duff
Keyword(s):  
Species Identification ◽  
Valence Electron ◽  
Chemical Species ◽  
X Rays ◽  
Chemical Bonds ◽  
Small Shift ◽  
X Ray ◽  
Electron Transitions ◽  
Peak Energy ◽  
Chemical Combination

A material irradiated with electrons emits x-rays having energies characteristic of the elements present. Chemical combination between elements results in a small shift of the peak energies of these characteristic x-rays because chemical bonds between different elements have different energies. The energy differences of the characteristic x-rays resulting from valence electron transitions can be used to identify the chemical species present and to obtain information about the chemical bond itself. Although these peak-energy shifts have been well known for a number of years, their use for chemical-species identification in small volumes of material was not realized until the development of the electron microprobe.

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