The Effects of the Temperature-Dependence of Properties on the Thermal Stresses in Cylinders

1980 ◽  
pp. 61-80 ◽  
Author(s):  
P. Stanley ◽  
F. S. Chau
Keyword(s):  
Temperature Dependence ◽  
Thermal Stresses

The Study of the Thermal Processes in an Electrode Influenced by an Electric Arc

2015 ◽  
Vol 792 ◽  
pp. 482-487
Author(s):  
Olga Dutova ◽  
Pavel Domarov ◽  
Tatiana Oschepkova
Keyword(s):  
Characteristic Feature ◽  
Temperature Dependence ◽  
Thermophysical Properties ◽  
Thermal Stresses ◽  
Electric Arc ◽  
Thermal Processes ◽  
Narrow Zone ◽  
Large Gradient

The effect of a moving arc spot on a material of a plasmatron electrode is considered in the present paper. Temperature-dependence of material thermophysical properties is taken into account. Dynamics of temperature and thermal stresses fields are calculated. The characteristic feature of temperatures distribution along radius of an electrode is large gradient of temperatures in a narrow zone near to a surface which can cause large thermostresses and microcracks.

Temperature dependence of stresses in GaN thin films grown on (0001) sapphire: Modeling of thermal stresses

2001 ◽  
Vol 79 (26) ◽  
pp. 4307-4309 ◽  
Author(s):  
J. Keckes ◽  
J. W. Gerlach ◽  
R. Averbeck ◽  
H. Riechert ◽  
S. Bader ◽  
...  
Keyword(s):  
Thin Films ◽  
Temperature Dependence ◽  
Thermal Stresses

Raman Thermometry of Polysilicon Microelectro-mechanical Systems in the Presence of an Evolving Stress

2006 ◽  
Vol 129 (3) ◽  
pp. 329-334 ◽  
Author(s):  
Mark R. Abel ◽  
Samuel Graham ◽  
Justin R. Serrano ◽  
Sean P. Kearney ◽  
Leslie M. Phinney
Keyword(s):  
Thermal Stress ◽  
Stress State ◽  
Spectral Characteristic ◽  
Temperature Dependence ◽  
Power Dissipation ◽  
Thermal Stresses ◽  
Stokes Shift ◽  
Stress Variation ◽  
Peak Location ◽  
Linewidth Broadening

In this work, the use of Raman Stokes peak location and linewidth broadening methods were evaluated for thermometry applications of polysilicon microheaters subjected to evolving thermal stresses. Calibrations were performed using the temperature dependence of each spectral characteristic separately, and the uncertainty of each method quantified. It was determined that the Stokes linewidth was independent of stress variation allowing for temperature determination, irrespective of stress state. However, the linewidth method is subject to greater uncertainty than the Stokes shift determination. The uncertainties for each method are observed to decrease with decreasing temperature and increasing integration times. The techniques were applied to mechanically constrained electrically active polysilicon microheaters. Results revealed temperatures in excess of 500°C could be achieved in these devices. Using the peak location method resulted in an underprediction of temperature due to the development of a relative compressive thermal stress with increasing power dissipation.

Optimal Cooling of Cross-Ply Composite Laminates and Adhesive Joints

1982 ◽  
Vol 49 (4) ◽  
pp. 735-739 ◽  
Author(s):  
Y. Weitsman ◽  
B. D. Harper
Keyword(s):  
Thermal Expansion ◽  
Residual Stresses ◽  
Temperature Dependence ◽  
Composite Laminates ◽  
Thermal Stresses ◽  
Viscoelastic Behavior ◽  
Adhesive Joints ◽  
Analytical Scheme ◽  
Polymeric Resins

This paper concerns the optimal cooling of symmetric, balanced, cross-ply composite laminates and adhesive joints so as to minimize the residual thermal stresses upon termination of the cool-down process. The computations are based on a recently developed analytical scheme and employ up-to-date data on graphite/epoxy laminas. The calculations consider the thermoviscoelastic response of the polymeric resins and incorporate the temperature dependence of the coefficients of thermal expansion. It is shown that the viscoelastic behavior may contribute to a significant reduction of the residual stresses.

scholarly journals Modeling of the temperature regime and stress state in the thermal sensitive pad-disk brake system

2018 ◽  
Vol 10 (6) ◽  
pp. 168781401878128 ◽  
Author(s):  
Aleksander Yevtushenko ◽  
Michal Kuciej ◽  
Ewa Och
Keyword(s):  
Temperature Dependence ◽  
Thermal Stresses ◽  
Heat Conduction Problem ◽  
Friction Pair ◽  
Linear Thermal Expansion ◽  
Temperature Fields ◽  
Disk Brake ◽  
Partial Linearization ◽  
Thermal Bending ◽  
Properties Of Materials

An analytical–numerical nonlinear model to investigate temperature fields and thermal stresses in a pad and a disk for a single braking with a constant deceleration has been proposed. For this purpose, the boundary-value heat conduction problem for a tribosystem strip–semi-space has been formulated, which takes into account the temperature dependence of the thermophysical properties of materials. The solution to this problem has been obtained by a partial linearization through the Kirchhoff substitution, and next with a subsequent use of the method of linearizing parameters. Knowing the distribution of temperature fields in the elements of a friction pair, the thermal stresses have been established within the theory of thermal bending of plates. In this case, the temperature dependence of the Young’s modulus, Poisson’s ratio, and linear thermal expansion of the pad and disk materials have been additionally taken into account. The numerical analysis has been performed for a friction pair consisting of a titanium alloy pad and a steel disk.

Temperature Dependence of the Critical Electron Dose for Fatty Acid Monolayers

1982 ◽  
Vol 40 ◽  
pp. 78-79
Author(s):  
Kenneth H. Downing ◽  
Robert M. Glaeser
Keyword(s):  
Electron Beam ◽  
Fatty Acid ◽  
Inelastic Scattering ◽  
Temperature Dependence ◽  
Structural Damage ◽  
Direct Result ◽  
Second Step ◽  
Strong Temperature Dependence ◽  
Electron Dose ◽  
Covalent Bonds

The structural damage of molecules irradiated by electrons is generally considered to occur in two steps. The direct result of inelastic scattering events is the disruption of covalent bonds. Following changes in bond structure, movement of the constituent atoms produces permanent distortions of the molecules. Since at least the second step should show a strong temperature dependence, it was to be expected that cooling a specimen should extend its lifetime in the electron beam. This result has been found in a large number of experiments, but the degree to which cooling the specimen enhances its resistance to radiation damage has been found to vary widely with specimen types.

Temperature Dependence of Magnetic Domains and Wall Structures

1972 ◽  
Vol 30 ◽  
pp. 496-497
Author(s):  
Sonoko Tsukahara ◽  
Tadami Taoka ◽  
Hisao Nishizawa
Keyword(s):  
Temperature Dependence ◽  
Domain Walls ◽  
Magnetic Domain ◽  
Iron Film ◽  
Objective Lens ◽  
Lorentz Microscopy ◽  
Domain Structures ◽  
Wall Structures ◽  
Crystal Films ◽  
Metallurgical Structure

The high voltage Lorentz microscopy was successfully used to observe changes with temperature; of domain structures and metallurgical structures in an iron film set on the hot stage combined with a goniometer. The microscope used was the JEM-1000 EM which was operated with the objective lens current cut off to eliminate the magnetic field in the specimen position. Single crystal films with an (001) plane were prepared by the epitaxial growth of evaporated iron on a cleaved (001) plane of a rocksalt substrate. They had a uniform thickness from 1000 to 7000 Å.The figure shows the temperature dependence of magnetic domain structure with its corresponding deflection pattern and metallurgical structure observed in a 4500 Å iron film. In general, with increase of temperature, the straight domain walls decrease in their width (at 400°C), curve in an iregular shape (600°C) and then vanish (790°C). The ripple structures with cross-tie walls are observed below the Curie temperature.

Deformation at interfaces of Ti-6Al-4V/SiC fiber composites

1992 ◽  
Vol 50 (1) ◽  
pp. 158-159
Author(s):  
Warren J. Moberly ◽  
Daniel B. Miracle ◽  
S. Krishnamurthy
Keyword(s):  
Thermal Stresses ◽  
Load Transfer ◽  
Coefficient Of Thermal Expansion ◽  
Hot Isostatic Pressing ◽  
Matrix Composites ◽  
Ongoing Research ◽  
Aerospace Applications ◽  
Sic Fiber ◽  
The Matrix ◽  
Intermetallic Matrix Composites

Titanium-aluminum alloy metal matrix composites (MMC) and Ti-Al intermetallic matrix composites (IMC), reinforced with continuous SCS6 SiC fibers are leading candidates for high temperature aerospace applications such as the National Aerospace Plane (NASP). The nature of deformation at fiber / matrix interfaces is characterized in this ongoing research. One major concern is the mismatch in coefficient of thermal expansion (CTE) between the Ti-based matrix and the SiC fiber. This can lead to thermal stresses upon cooling down from the temperature incurred during hot isostatic pressing (HIP), which are sufficient to cause yielding in the matrix, and/or lead to fatigue from the thermal cycling that will be incurred during application, A second concern is the load transfer, from fiber to matrix, that is required if/when fiber fracture occurs. In both cases the stresses in the matrix are most severe at the interlace.

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