scholarly journals Mutual Influence of Geometric Parameters and Mechanical Properties on Thermal Stresses in Composite Laminated Plates with Rectangular Holes

Mathematics ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 311
Author(s):  
Mohammad Hossein Bayati Chaleshtari ◽  
Mohammad Jafari ◽  
Hadi Khoramishad ◽  
Eduard-Marius Craciun
Keyword(s):  
Mechanical Properties ◽  
Heat Flux ◽  
Thermal Stress ◽  
Stress Distribution ◽  
Thermal Stresses ◽  
Mutual Influence ◽  
Geometric Parameters ◽  
Stacking Sequence ◽  
Rectangular Hole ◽  
Thermal Stress Distribution

In this research, the mutual influence of the mechanical properties and geometric parameters on thermal stress distribution in symmetric composite plates with a quasi-rectangular hole subjected to uniform heat flux is examined analytically using the complex variable technique. The analytical solution is obtained based on the thermo-elastic theory and the Lekhnitskii’s method. Furthermore, by employing a suitable mapping function, the solution of symmetric laminates containing a circular hole is extended to the quasi-rectangular hole. The effect of important parameters including the stacking sequence of laminates, the angular position, the bluntness, and the aspect ratio of the hole and the flux angle in the stacking sequence of [45/−45]s for composite materials are examined in relation to the thermal stress distribution. The thermal insulated state and Neumann boundary conditions at the hole edge are taken into account. It is found out that the hole rotation angles and heat flux angle play key roles in obtaining the optimum thermal stress distribution around the hole. The present analytical method can well investigate the interaction of effective parameters on symmetric multilayer composites under heat flux.

scholarly journals Thermal Analysis of Si/GaAs Bonding Wafers and Mitigation Strategies of the Bonding Stresses

2017 ◽  
Vol 2017 ◽  
pp. 1-8
Author(s):  
Yuanying Qiu ◽  
Xun Qiu ◽  
Xianghu Guo ◽  
Dian Wang ◽  
Lijie Sun
Keyword(s):  
Finite Element Method ◽  
Thermal Stress ◽  
Stress Distribution ◽  
Wafer Bonding ◽  
Thermal Stresses ◽  
Annealing Process ◽  
Mitigation Strategies ◽  
Stress Theory ◽  
Effective Strategies ◽  
Thermal Stress Distribution

In order to effectively reduce the thermal stresses of Si/GaAs bonding wafers during their annealing process, first of all, based on E. Suhir’s bimaterial thermal stress theory, the thermal stresses in the wafer bonding interfaces are analyzed and the thermal stress distribution formulas are obtained. Then, the thermal stress distribution curves of Si/GaAs bonding interfaces are investigated by finite element method (FEM) and are compared with the results from E. Suhir’s bimaterial thermal stress theory. Finally, some effective strategies are proposed to reduce the thermal stresses in the bonding interfaces.

scholarly journals INFLUENCE OF THE MODEL SIZE IN THE NUMERICAL DETERMINATION OF THE AVERAGE THERMAL STRESSES IN AN MMC COMPOSITE

2011 ◽  
Vol 10 (1-2) ◽  
pp. 23
Author(s):  
C. A. de J. Miranda ◽  
R. M. P. Libardi ◽  
S. Marcelino ◽  
Z. M. de Boari
Keyword(s):  
Thermal Stress ◽  
Stress Distribution ◽  
Thermal Stresses ◽  
Metallic Matrix ◽  
Aluminum Matrix ◽  
High Strength ◽  
Plastic Behavior ◽  
Non Linear ◽  
Model Size ◽  
Thermal Stress Distribution

In previous works the authors discussed some issues related to a specific metallic matrix composites (MMC), the Aluminum matrix reinforced with SiC particles (Al+SiC) which has a metal matrix (powder) mixed with ceramic particles. These materials have some advantages when used as a structural material such as their high strength and good conformability. Their properties depend, among others, on the volumetric ratio, the  particles size and distribution besides the matrix microstructure itself. Some of them are obtained at elevated temperature what produces a thermal stress state in the material. The Al+SiC is one of the later. The powder mix is extruded at 600oC and it is used at 20oC. Several numerical analyses were performed considering the random distribution of the particles and a non-linear behavior in the aluminum matrix. The results showed strong influence of the aluminum elastic-plastic behavior in the composite thermal stress distribution due to its manufacturing process. However, one issue remained: the size of the model. It represents the central portion of a Al+SiC bar which is only about 10 times the size of a single particle (~10L). The present work investigates, always numerically, the influence of the model size on the thermal stress distribution. It considers 2 sets of non-linear analyses with random distributed particles: one with 20 models with size of 20L each one, the other set with another 20 models with size 40L. This approach allows a view of the results tendency compared with the 10L ones. As done before, the modeled volumetric ratio has a very tight range of values with its average very near to the value in an actual Al+SiC composite. It is showed that the first model size was already enough to get good results without sacrificing neither the computer nor the analyst time.

Optimization of Material Composition of FGM Coating under Steady Heat Flux Loading by Micro-Genetic Algorithms

2005 ◽  
Vol 492-493 ◽  
pp. 441-446 ◽  
Author(s):  
Jian Ping Wang ◽  
Gang Chen ◽  
Peng Cheng Zhai
Keyword(s):  
Heat Flux ◽  
Thermal Stress ◽  
Stress Distribution ◽  
Volume Fraction ◽  
Infinite Plate ◽  
Ceramic Surface ◽  
Composition Distribution ◽  
Flowing Liquid ◽  
Thermal Stress Distribution ◽  
Steady Heat

This paper studies the optimization problem of composition distribution of functionally graded material (FGM) coating subjected to steady heat flux loading. The investigation object of the paper is an infinite plate substrate with FGM coating in the surface. The materials are heated at the ceramic surface (upside) with a steady high-intensity heat flux input, and cooled at the metal surface (underside) with flowing liquid nitrogen. The thermal stress distribution and the temperature distribution are obtained by formulation. For optimization, the design variables are the thickness of each interlayer and the volume fraction distribution of the coating. The objective function is the danger coefficient and the restricted condition is the total thickness of FGM plate and heat insulation coefficient. In the paper, three different optimization schemes are considered and compared. The µGA and related parameters are discussed in detail. Optimizing the thermal stress distribution and minimizing the danger coefficient are carried out by µGA. The optimization results of composition distribution are gained, and the results show the optimum composition distribution can distinctly reduce the danger coefficient.

Analysis of Thermal Stress in Cryosurgery of Kidneys

2004 ◽  
Author(s):  
Xiaoming He ◽  
John C. Bischof
Keyword(s):  
Mechanical Properties ◽  
Thermal Stress ◽  
Stress Distribution ◽  
Element Model ◽  
Renal Tissue ◽  
Computational Effort ◽  
Renal Capsule ◽  
Tissue Water ◽  
Sharp Point ◽  
Thermal Stress Distribution

In this study, the thermal stress distribution in cryosurgery of kidney was investigated using a multi-physics finite element model developed in ANSYS (V7.0). The thermal portion of the model was verified using experimental data and the mechanics portion of the model (elastic) was verified using classic analytical solutions. Temperature dependent thermal and mechanical properties were used in the model. Moreover, the model accounts for thermal expansion due to both temperature change and volumetric expansion associated with phase change of tissue water to ice. For a clinical cylindrical cryoprobe inserted into the renal cortex from the top-middle renal capsule, it was found that the thermal stress distributions along the radial position are very different at different depths from the top renal capsule. The thermal stress is much higher at both ends than in the middle of the cryoprobe surface. It was found that there might be more tissue next to the top renal capsule which undergoes microcrack formation or plastic deformation. Furthermore, it was found that macrocrack formation is more likely to occur in tissue adjacent to the cryoprobe surface (especially on the sharp point tip) and during the thawing phase of cryosurgery. Because the thermal stress adjacent to the cryoprobe is much higher than the yield stress of frozen renal tissue, a plastic stress model is required for better modeling of the thermal stress distribution in cryosurgery of kidney in future although the computational effort will be drastically increased due to the strong nonlinear nature of the plastic model and more studies are required to understand the mechanical properties of frozen tissue.

Finite Element Analysis of Thermal Stress Distribution in Planar SOFC

2019 ◽  
Vol 7 (1) ◽  
pp. 1977-1986 ◽  
Author(s):  
Chih-Kuang Lin ◽  
Tsung-Ting Chen ◽  
An-Shin Chen ◽  
Yau-Pin Chyou ◽  
Lieh-Kwang Chiang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Thermal Stress ◽  
Stress Distribution ◽  
Element Analysis ◽  
Thermal Stress Distribution

Surface thermal stress distribution and the influence factors of Sapphire/AlN/GaN epilayers

2016 ◽  
Vol 45 (10) ◽  
pp. 1021001
Author(s):  
陈 靖 Chen Jing ◽  
程宏昌 Cheng Hongchang ◽  
吴玲玲 Wu Lingling ◽  
冯 刘 Feng Liu ◽  
苗 壮 Miao Zhuang
Keyword(s):  
Thermal Stress ◽  
Stress Distribution ◽  
Influence Factors ◽  
Thermal Stress Distribution
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