scholarly journals Second-Order Parabolic Equation to Model, Analyze, and Forecast Thermal-Stress Distribution in Aircraft Plate Attack Wing–Fuselage

Mathematics ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 6
Author(s):  
Giovanni Angiulli ◽  
Salvatore Calcagno ◽  
Domenico De Carlo ◽  
Filippo Laganá ◽  
Mario Versaci
Keyword(s):  
Thermal Stress ◽  
Thermal Load ◽  
Thermal Stresses ◽  
Steel Plate ◽  
Second Order ◽  
Parabolic Partial Differential Equation ◽  
Flight Altitude ◽  
Aeronautical Industry ◽  
Thermal Stress Distribution ◽  
Element Technique

During a flight, the steel plate attack wing–fuselage of an aircraft is subjected to cyclical thermal stress caused by flight altitude variation that could compromise the functionality of the plate. Thus, it is compulsory after a sequence of flights to evaluate the state of plate health. In this work, we propose a new dynamic model on the basis of the physical transmission of heat by conduction governed by a second-order parabolic partial differential equation with suitable initial and boundary conditions to analyze and forecast thermal stresses in the plate of a P64 OSCAR B airplane. Developing this model in the COMSOL Multi-Physics® environment, a finite-element technique was applied to achieve the thermal-stress map on the plate. The achieved results, equivalent to those obtained by a campaign of infrared thermographic experiment measurements (not yet used in the aeronautical industry), highlight the evolution of the thermal load of the steel plate attack wing–fuselage, adding evidence of possible incoming fatigue phenomena to identify in advance if the steel plate must be replaced.

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.

Thermal Stress CAD Analysis of a Multi-Layer Composite of an Operating Transistor Package

1990 ◽  
Vol 112 (1) ◽  
pp. 77-80
Author(s):  
Agha J. Ghorieshi ◽  
Umid R. Nejib
Keyword(s):  
Thermal Stress ◽  
Thermal Stresses ◽  
Cooling System ◽  
Three Dimensional ◽  
Heat Transfer Analysis ◽  
Temperature Cycle ◽  
Shear Stresses ◽  
Layer Composite ◽  
Convection Cooling ◽  
Element Technique

Thermal stress management is a major factor in the design of an electronic package. Thermal mismatch among the assembled components induces thermal stresses within the device. Finite element technique is utilized for three dimensional thermal stress analysis of a transistor with a free convection cooling system. Heat transfer analysis is used to determine the temperature distribution throughout the package for a given operating temperature. The data are then used to determine package stresses. The results show the shear stress concentration is higher at the corner of the chip. These values were found to be lower compared to those using temperature cycle analysis. An alternative method of lowering shear stresses in the chip is suggested.

Analysis of Thermal Stresses in 304 Stainless Steel Plate-Fin Structure

2013 ◽  
Vol 681 ◽  
pp. 286-290
Author(s):  
Huai Xiang Cao ◽  
Xing Qi Qiu ◽  
Wen Chun Jiang
Keyword(s):  
Stainless Steel ◽  
Thermal Stresses ◽  
Steel Plate ◽  
Filler Metal ◽  
Plate Thickness ◽  
304 Stainless Steel ◽  
Stainless Steel Plate ◽  
Metal Thickness ◽  
Thermal Stress Distribution ◽  
Fin Thickness

Thermal stresses in 304 stainless steel plate-fin structure at steady condition were calculated by finite element method. A squential coupling calculation procedure was developed to obtain the temperature and thermal stress distribution. The effects of plate thickness, fin thickness and filler metal thickness on thermal stresses were discussed. The results show that the thermal stresses in plate-fin structure are complex and nonuniform. The peak thermal stresses are shown in the fillet. With the plate thickness and fin thickness increasing, the thermal stresses are increased. The peak stresses are decreased as the filler metal thickness increasing.

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 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.

Thermal Stress Analysis of MCM Package Using Diamond Material

2007 ◽  
Vol 353-358 ◽  
pp. 2904-2907
Author(s):  
Kuo Jun Xie ◽  
Chang Shun Jiang ◽  
Lin Zhu ◽  
Hai Feng Xu
Keyword(s):  
Finite Element ◽  
Thermal Stress ◽  
Thermal Stresses ◽  
Geometrical Structure ◽  
Integrate Circuit ◽  
Stress Model ◽  
Temperature Distributions ◽  
Thermal Stress Distribution ◽  
On Chip ◽  
Quantity Of Heat

With the increasing of packaging integration the power and the quantity of heat of integrate circuit will increase, it will bring more and more temperature distributions and problems about thermal stresses in package. In this paper a finite element thermal stress model of substrate-adhesive-chip is established, thermal stress distribution of substrate-chip interfaces and the affects of geometrical structure on thermal stresses are analyzed by finite element method, especially discuss interfacial thermal stresses distributions on chip-adhesive interface and adhesinve-substrate interface.

Three Turnaround Heat Treating Studies

2003 ◽  
Author(s):  
Jaan Taagepera ◽  
Marty Clift ◽  
D. Mike DeHart ◽  
Keneth Marden
Keyword(s):  
Heat Treatment ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Thermal Stress ◽  
Thermal Stresses ◽  
Heat Treating ◽  
Element Analysis ◽  
Stress Profiles ◽  
Insight Into

Three vessel modifications requiring heat treatment were analyzed prior to and during a planned turnaround at a refinery. One was a thick nozzle that required weld build up. This nozzle had been in hydrogen service and required bake-out to reduce the potential for cracking during the weld build up. Finite element analysis was used to study the thermal stresses involved in the bake-out. Another heat treatment studied was a PWHT of a nozzle replacement. The heat treatment band and temperature were varied with location in order to minimize cost and reduction in remaining strength of the vessel. Again, FEA was used to provide insight into the thermal stress profiles during heat treatment. The fmal heat treatment study was for inserting a new nozzle in a 1-1/4Cr-1/2Mo reactor. While this material would ordinarily require PWHT, the alteration was proposed to be installed without PWHT. Though accepted by the Jurisdiction, this nozzle installation was ultimately cancelled.

Steady-State Thermal Stresses in Wedge-Shaped Cutting Tools

1975 ◽  
Vol 97 (3) ◽  
pp. 1060-1066
Author(s):  
P. F. Thomason
Keyword(s):  
Thermal Stress ◽  
Steady State ◽  
Metal Cutting ◽  
Thermal Stresses ◽  
Heat Conduction Problem ◽  
Equivalent Stress ◽  
Cutting Tools ◽  
Thermoelastic Stress ◽  
Plastic State ◽  
Steady State Heat

Closed form expressions for the steady-state thermal stresses in a π/2 wedge, subject to constant-temperature heat sources on the rake and flank contact segments, are obtained from a conformal mapping solution to the steady-state heat conduction problem. It is shown, following a theorem of Muskhelishvili, that the only nonzero thermal stress in the plane-strain wedge is that acting normal to the wedge plane. The thermal stress solutions are superimposed on a previously published isothermal cutting-load solution, to give the complete thermoelastic stress distribution at the wedge surfaces. The thermoelastic stresses are then used to determine the distribution of the equivalent stress, and this gives an indication of the regions on a cutting tool which are likely to be in the plastic state. The results are discussed in relation to the problems of flank wear and rakeface crater wear in metal cutting tools.

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