Transient thermoelastic investigation of FGM composite plate with varying grading parameter

2016 ◽  
Vol 232 (6) ◽  
pp. 441-452 ◽  
Author(s):  
Rajesh Sharma ◽  
Vijay Kumar Jadon ◽  
Balkar Singh ◽  
Neeraj Sharma
Keyword(s):  
High Temperature ◽  
Gas Turbines ◽  
Thermal Stresses ◽  
Three Dimensional ◽  
Electronics Cooling ◽  
Functionally Graded ◽  
Effect Of Temperature ◽  
Integration Scheme ◽  
Graded Materials ◽  
Safe Limits

Functionally graded materials (FGM) are newly developed materials described by variation in the characteristics gradually over volume. These materials find applications in very high temperature environments namely aerospace industry, nuclear reactors, gas turbines, and electronics cooling. These materials are used in high temperature environments with dynamic load conditions, so their transient thermoelastic analysis under these conditions is necessary. In this paper, transient thermoelastic investigation of FGM is carried out using finite element method (FEM). The effect of temperature dependence is considered in the thermophysical properties of a FGM plate in the direction of its thickness. FEM is applied to solve the thermo mechanical equations and Newmark direct integration scheme is used for obtaining the solution for transient loading. This method improves the accuracy for three dimensional cases and produces solutions directly in time domain. A comparative study is made with some existing methods, and it is found that temperature and thermal stresses remain within safe limits at higher temperatures while preserving the deformation in the structure. The results show that the grading parameter has a dominating effect on transient thermoelastic behavior on FGM plate.

scholarly journals Three-Dimensional Finite Element Modeling of Thermomechanical Problems in Functionally Graded Hydroxyapatite/Titanium Plate

2014 ◽  
Vol 2014 ◽  
pp. 1-20 ◽  
Author(s):  
S. N. S. Jamaludin ◽  
S. Basri ◽  
Ahmad Hussain ◽  
Dheya Shujaa Al-Othmany ◽  
F. Mustapha ◽  
...  
Keyword(s):  
Thermal Stresses ◽  
Three Dimensional ◽  
Metallic Phase ◽  
Functionally Graded ◽  
Thermomechanical Model ◽  
Graded Materials ◽  
Ceramic Phase ◽  
Fg Plates ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

The composition of hydroxyapatite (HA) as the ceramic phase and titanium (Ti) as the metallic phase in HA/Ti functionally graded materials (FGMs) shows an excellent combination of high biocompatibility and high mechanical properties in a structure. Because the gradation of these properties is one of the factors that affects the response of the functionally graded (FG) plates, this paper is presented to show the domination of the grading parameter on the displacement and stress distribution of the plates. A three-dimensional (3D) thermomechanical model of a 20-node brick quadratic element is used in the simulation of the thermoelastic behaviors of HA/Ti FG plates subjected to constant and functional thermal, mechanical, and thermomechanical loadings. The convergence properties of the present results are examined thoroughly in order to assess the accuracy of the theory applied and to compare them with the established research results. Instead of the grading parameter, this study reveals that the loading field distribution can be another factor that reflects the thermoelastic properties of the HA/Ti FG plates. The FG structure is found to be able to withstand the thermal stresses while preserving the high toughness properties and thus shows its ability to operate at high temperature.

Computational Models for High-Temperature Multilayered Composite Plates and Shells

1992 ◽  
Vol 45 (10) ◽  
pp. 419-446 ◽  
Author(s):  
Ahmed K. Noor ◽  
W. Scott Burton
Keyword(s):  
High Temperature ◽  
Computational Models ◽  
Thermal Stresses ◽  
Three Dimensional ◽  
Composite Plates ◽  
Effect Of Temperature ◽  
Temperature Sensitive ◽  
Composite Models ◽  
Sandwich Plates And Shells ◽  
Plates And Shells

The focus of this review is on the hierarchy of composite models, predictor-corrector procedures, the effect of temperature-dependence of material properties on the response, and the sensitivity of the thermomechanical response to variations in material parameters. The literature reviewed is devoted to the following eight application areas: Heat transfer; thermal stresses; curing, processing and residual stresses; bifurcation buckling; vibrations of heated plates and shells; large deflection and postbuckling problems; and sandwich plates and shells. Extensive numerical results are presented showing the effects of variation in the lamination and geometric parameters of temperature-sensitive angle-ply composite plates on the accuracy of thermal buckling response, and the sensitivity derivatives predicted by nine different modeling approaches (based on two-dimensional theories). The standard of comparison is taken to be the exact three-dimensional thermoelasticity solutions. Some future directions for research on the modeling of high-temperature multilayered composites are outlined.

A Multiscale NDT System for Damage Detection in Thermal Barrier Coatings

2009 ◽  
Author(s):  
A. M. G. Luz ◽  
D. Balint ◽  
K. Nikbin
Keyword(s):  
High Temperature ◽  
Damage Detection ◽  
Luminescence Spectrum ◽  
Bond Coat ◽  
Gas Turbines ◽  
Thermal Stresses ◽  
Assessment Tool ◽  
Diagnostic Tools ◽  
Spectral Parameters ◽  
Temperature Oxidation

Progress in aero-engines and land-based gas turbines is continuously linked with a rise of the operating temperature. TBCs are multilayered structures which function together to effectively lower the temperature of its load-bearing superalloy substrate while simultaneously providing oxidation protection against high temperature combustion environments during operation. They typically comprise of a ceramic top coat for thermal insulation and a metallic bond coat that provides oxidation/corrosion resistance and enhances the adhesion of the YSZ to the superalloy substrate. Due to high-temperature oxidation of the bond coat, a thermally grown oxide (TGO) scale of continuous Al2O3 is formed between the ceramic top coat and the bond coat. The formation and growth of the TGO increases the mismatch of thermal expansion coefficients among the multilayered TBC and induce high thermal stresses leading to spallation of the YSZ coat from the underlying metal. Hence, nondestructive diagnostic tools that could reliably probe the subsurface damage state of TBCs are essential to take full advantage of these systems. In this contribution, a new concept of multiscale NDT system is presented. The instrument uses a combination of imaging-based methods with photoluminescence piezospectroscopy, a laser-based method. Imaging-based methods like mid-infrared reflectance, laser optical backscatter and infrared tomography were used to predict the overall lifetime of the coated component. When TBCs approach the end of life, micro-crack nucleation and propagation at the top coat/bond coat interface increases the amount of reflected light. This rise in reflectance was correlated with the lifetime of the component using a neural network that merges the mean and standard deviation value of the gray level. Photoluminescence piezospectroscopy was subsequently used to give information about the structural integrity of the hot spots identified in the image analysis. This laser-based technique measures in-situ the residual stress in the TGO at room temperature. Damage leads to a relaxation of the local stress which is in turn reflected in the luminescence spectrum shape. However, presently there is no agreement on the best spectral parameters that should be used as a measure of the damage accumulation in the coatings. Therefore, the evolution of luminescence spectrum from as-manufactured to critically damaged TBCs was determined using the finite element method. This approach helped to identify the most suitable spectral parameters for damage detection, improving the reliability of photoluminescence piezospectroscopy as a failure assessment tool for TBCs.

Transient Analysis of a Ceramic High Temperature Heat Exchanger and Chemical Decomposer

2007 ◽  
Author(s):  
Valery Ponyavin ◽  
Taha Mohamed ◽  
Mohamed Trabia ◽  
Yitung Chen ◽  
Anthony E. Hechanova
Keyword(s):  
Steady State ◽  
High Temperature ◽  
Heat Exchanger ◽  
Thermal Stresses ◽  
Three Dimensional ◽  
Failure Criteria ◽  
Operating Conditions ◽  
Finite Element Software ◽  
Micro Channels ◽  
Temperature Heat

Ceramics are suitable for use in high temperature applications as well as corrosive environment. These characteristics were the reason behind selection silicone carbide for a high temperature heat exchanger and chemical decomposer, which is a part of the Sulphur-Iodine (SI) thermo-chemical cycle. The heat exchanger is expected to operate in the range of 950°C. The proposed design is manufactured using fused ceramic layers that allow creation of micro-channels with dimensions below one millimeter. A proper design of the heat exchanges requires considering possibilities of failure due to stresses under both steady state and transient conditions. Temperature gradients within the heat exchanger ceramic components induce thermal stresses that dominate other stresses. A three-dimensional computational model is developed to investigate the fluid flow, heat transfer and stresses in the decomposer. Temperature distribution in the solid is imported to finite element software and used with pressure loads for stress analysis. The stress results are used to calculate probability of failure based on Weibull failure criteria. Earlier analysis showed that stress results at steady state operating conditions are satisfactory. The focus of this paper is to consider stresses that are induced during transient scenarios. In particular, the cases of startup and shutdown of the heat exchanger are considered. The paper presents an evaluation of the stresses in these two cases.

An Analysis of Thermo-Mechanical Behavior in a Multilayer Composite Pipe Under Temperature Variation

2010 ◽  
Author(s):  
Wei Yang ◽  
Jyhwen Wang
Keyword(s):  
Finite Element ◽  
Thermal Stress ◽  
Analytical Solution ◽  
Mechanical Behavior ◽  
Temperature Change ◽  
Thermal Stresses ◽  
Element Model ◽  
Functionally Graded ◽  
Element Analysis ◽  
Graded Materials

A generalized analytical solution of mechanical and thermal induced stresses in a multi-layer composite cylinder is presented. Based on the compatibility condition at the interfaces, an explicit solution of mechanical stress due to inner and outer surface pressures and thermal stress due to temperature change is derived. A finite element model is also developed to provide the comparison with the analytical solution. It was found that the analytical solutions are in good agreement with finite element analysis result. The analytical solution shows the non-linear dependency of thermal stress on the diameters, thicknesses and the material properties of the layers. It is also shown that the radial and circumferential thermal stresses depend linearly on the coefficients of thermal expansion of the materials and the temperature change. As demonstrated, this solution can also be applied to analyze the thermo-mechanical behavior of pipes coated with functionally graded materials.

Hot Dynamic Densification of Materials by Utilizing Underwater Shock Wave

2012 ◽  
Vol 706-709 ◽  
pp. 793-798 ◽  
Author(s):  
Ryuichi Tomoshige ◽  
Seiichiro Ii ◽  
Masahiro Fujita ◽  
Akira Chiba
Keyword(s):  
High Temperature ◽  
Ceramic Composites ◽  
Functionally Graded ◽  
Underwater Shock Wave ◽  
Graded Materials ◽  
High Temperature Synthesis ◽  
Two Phases ◽  
Tini Phase ◽  
Short Time ◽  
Dynamic Densification

Hot dynamic densification method was developed by combining self-propagating high temperature synthesis (SHS) with explosively shock powder compaction technique. This method is extremely short time processing. The main purpose in this study is to perform from synthesis to densification of TiB2-TiN system high temperature ceramic composites and TiB2-TiNi-Cu system functionally graded materials (FGMs) in one step. In TiN-TiB2 ceramic composites, they showed up to 95% of relative density. It was appeared by TEM observations that both the two phases joined tightly each other. The FGMs also were produced by the same technique. They indicated no interlayer exfoliation and no macro cracks after thermal shock tests from 973 K to room temperature. It was shown that thermoelastic property of intermetallic TiNi phase as intermediate layer between ceramics and metal layers operated effectively.

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