Thermal shock-induced Moore-Gibson-Thompson generalized coupled thermoelasticity analysis based on the strain gradient Love-Bishop theory in a nanorod resonator

Meccanica ◽  
2022 ◽  
Author(s):  
Seyed Mahmoud Hosseini ◽  
Fengming Li
Keyword(s):  
Thermal Shock ◽  
Strain Gradient ◽  
Coupled Thermoelasticity

Coupled thermoelasticity of FG-GPLRC multi-curved composite panel under thermal shock loading

2021 ◽  
pp. 114515
Author(s):  
Qiangfeng Wang ◽  
Jun Gao ◽  
Shengbin Wu ◽  
Mohamed Amine Khadimallah ◽  
Huiwei Chen
Keyword(s):  
Thermal Shock ◽  
Shock Loading ◽  
Composite Panel ◽  
Coupled Thermoelasticity

Generalized Thermoelasticity Theories for Axisymmetric Hollow Cylinders Under Thermal Shock with Variable Thermal Conductivity

2018 ◽  
Vol 06 (03n04) ◽  
pp. 1850006
Author(s):  
Ashraf M. Zenkour
Keyword(s):  
Thermal Conductivity ◽  
Thermal Shock ◽  
Generalized Thermoelasticity ◽  
Present Theory ◽  
Variable Thermal Conductivity ◽  
Coupled Thermoelasticity ◽  
Heating Source ◽  
Special Cases ◽  
Hollow Cylinders ◽  
Time Parameters

The thermoelastic problem of clamped axisymmetric infinite hollow cylinders under thermal shock with variable thermal conductivity is presented. The outer surface of infinite hollow cylinder is considered to be thermally insulated while inner surface is subjected to an initial heating source. In addition, the cylinder is considered to be clamped at its inner and outer radii. Generalized thermoelasticity theories are used to deal with the field quantities. All generalized thermoelasticity theories such as Green and Lindsay, Lord and Shulman, and coupled thermoelasticity (CTE) are considered as special cases of the present theory. Effects of variable thermal conductivity and time parameters on radial displacement, temperature, and stresses of the hollow cylinders are investigated.

Modification of Shock Resistance for Cutting Tools Using Functionally Graded Concept in Multilayer Coating

2015 ◽  
Vol 7 (1) ◽  
Author(s):  
M. R. Vaziri ◽  
S. M. Nowruzpour Mehrian ◽  
M. H. Naei ◽  
Jamal Y. Sheikh Ahmad
Keyword(s):  
Thermal Shock ◽  
Multilayer Coating ◽  
Cutting Tools ◽  
Milling Process ◽  
Functionally Graded ◽  
Sound Effect ◽  
Laplace Domain ◽  
Coupled Thermoelasticity ◽  
Coupled Equations ◽  
Temperature Levels

In this study, thermal analysis and optimization of the material composition in functionally graded (FG) cutting tools were carried out to achieve the minimum thermal stress. Since cutting tool particularly rotating ones in milling process are exposed to thermal shock during machining, a complicated analysis is required to analyze the thermal shock response. Therefore, a generalized coupled thermoelasticity theory of Lord–Shulman based on second sound effect is adopted. Lord–Shulman theory, as a generalized coupled thermoelasticity, is chosen as governing equation in terms of temperature and displacement. The coupled equations are transferred to Laplace domain and then Galerkin finite element method is employed to solve the equation in the Laplace domain. Then, a numerical Laplace inversion has been applied to transform back the equation from Laplace domain to real time. Results are obtained for several material compositions so that the proper composition will be found for design. It is shown that FG materials (FGMs) exhibit lower stresses, lower displacement, and lower temperature levels compared to multilayer materials. Furthermore, the effect of FGM is increased by increasing the power law index, representing the change in concentration.

A controller for safe, convenient operation of LaB6 emitters on electron-beam instruments

1983 ◽  
Vol 41 ◽  
pp. 408-409
Author(s):  
W. J. Abramson ◽  
H. W. Estry ◽  
L. F. Allard
Keyword(s):  
Electron Beam ◽  
Control System ◽  
Thermal Shock ◽  
Appropriate Care ◽  
Electron Guns ◽  
Tungsten Filaments ◽  
Order Of Magnitude ◽  
Main Components

LaB6 emitters are becoming increasingly popular as direct replacements for tungsten filaments in the electron guns of modern electron-beam instruments. These emitters offer order of magnitude increases in beam brightness, and, with appropriate care in operation, a corresponding increase in source lifetime. They are, however, an order of magnitude more expensive, and may be easily damaged (by improper vacuum conditions and thermal shock) during saturation/desaturation operations. These operations typically require several minutes of an operator's attention, which becomes tedious and subject to error, particularly since the emitter must be cooled during sample exchanges to minimize damage from random vacuum excursions. We have designed a control system for LaBg emitters which relieves the operator of the necessity for manually controlling the emitter power, minimizes the danger of accidental improper operation, and makes the use of these emitters routine on multi-user instruments.Figure 1 is a block schematic of the main components of the control system, and Figure 2 shows the control box.

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