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.

A Simplified Thermal Load Evaluation Method for Localized Lug Stresses Beyond Sec. III Appendix-Y

2019 ◽  
Author(s):  
Tsubasa Matsumiya ◽  
Daniel Garcia-Rodriguez ◽  
Akira Nebu ◽  
Noriyuki Takamura
Keyword(s):  
Thermal Stresses ◽  
Evaluation Method ◽  
Three Dimensional ◽  
Parameter Study ◽  
Element Analysis ◽  
Class 1 ◽  
Dimensional Finite Element ◽  
3D Fea ◽  
Three Dimensional Finite Element ◽  
Load Evaluation

Abstract In this work an evaluation method for local thermal stresses on class 1 piping due to U-shaped lugs is presented. First, a three-dimensional finite element analysis (3D-FEA) is used to perform a thermal transient evaluation, obtaining the time-dependent temperature distribution of a realistic range of pipe-lug systems. These results are then used as an input for both a structural 3D-FEA and the corresponding thermal stress term in Non-Mandatory Appendix Y [1]. It was seen that the formula in Appendix-Y cannot account for the thermal stresses obtained through the detailed FEA evaluation. A parameter study using a simplified two-dimensional (2D) FEA approach, shows that the localized thermal stresses due to lugs are significantly affected by: (1) pipe-to-lug thickness ratio, (2) distance between adjacent lugs, and (3) lug height. A set of correction coefficients depending on these parameters is therefore proposed. When applying the proposed correction coefficients to the Appendix Y method, adequately conservative (when compared with 3D FEA results) stresses can be obtained. Since these correction coefficients can be obtained from simple geometric considerations, the proposed method successfully accounts for the complex lug-to-lug interaction while retaining the simplicity of the original Appendix Y approach.

FINITE ELEMENT ANALYSIS OF THE THERMAL BEHAVIOUR OF SINGLE-DISC CLUTCHES DURING REPEATED ENGAGEMENTS

Tribologia ◽  
2016 ◽  
Vol 266 (2) ◽  
pp. 9-24 ◽  
Author(s):  
Oday I. ABDULLAH ◽  
Laith Abed SABRI ◽  
Wassan S. Abd Al-SAHB
Keyword(s):  
Finite Element ◽  
Thermal Behaviour ◽  
Thermal Stresses ◽  
Three Dimensional ◽  
Finite Element Models ◽  
Element Analysis ◽  
Premature Failure ◽  
Friction Clutch ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Most of the failures in the sliding systems occur due to the high thermal stresses, which generated at the interface between the contacting surfaces due to sliding between parts, such as friction clutches and brakes. In this paper, the thermal behaviour of a single-disc clutch is investigated. The surface temperatures of the friction clutch disc will be increased during repeated engagements, in some cases, will lead to premature failure of the clutch disc. In order to avoid this kind of failure, it the surface temperature should be calculated with high accuracy to know the maximum working temperature of the friction system. In this work, the temperature distributions are computed during four repeated engagements at regular intervals (5 s) for the same energy dissipation. Three-dimensional finite element models are used to simulate the typical friction clutch disc.

External Longitudinal Flaws in Pipes Under Complex Loading

2000 ◽  
Vol 123 (1) ◽  
pp. 139-145 ◽  
Author(s):  
Roberto Brighenti
Keyword(s):  
Thermal Stresses ◽  
Superposition Principle ◽  
Three Dimensional ◽  
Complex Loading ◽  
Stress Distributions ◽  
Power Series Expansions ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Hoop Stresses ◽  
Crack Faces

A round pipe with an external longitudinal surface flaw is assumed to be subjected to different types of elementary hoop stress distributions acting perpendicular to the crack faces. The stress intensity factors (SIFs) along the crack front for such elementary cases are determined through the three-dimensional finite element method. Then these results are used to compute approximate values of SIFs in the case of complex loadings (such as internal pressure, thermal stresses, residual stresses due to plasticization, etc.), by employing both the superposition principle and the power series expansions of the actual hoop stresses. Thick and thin-walled pipes are examined, and some results are compared with those presented by other authors.

Three-Dimensional Finite Element Calculations of Thermal Stresses in Patterned GaAs / Si

1991 ◽  
Vol 239 ◽  
Author(s):  
E. H. Lingunis ◽  
N. M. Haegel ◽  
N. H. Karam
Keyword(s):  
Finite Element ◽  
Thermal Stresses ◽  
Stress Measurement ◽  
Three Dimensional ◽  
Biaxial Stress ◽  
Luminescence Spectra ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Free Edges

ABSTRACTThree-dimensional elastic finite element analysis was used to investigate the stress state in patterned GaAs/Si squares with different width to thickness ratios. Quantitative results for stress relief close to free edges were obtained. Features not revealed by previous two-dimensional calculations show the necessity of the three-dimensional treatment. For large areas the calculations give an approximately uniform biaxial stress everywhere, with reduced magnitude close to free edges. This allows for straightforward interpretation of high spatial resolution luminescence spectra and precise stress measurement. Experimental results from low temperature photoluminescence show good agreement with the calculated stresses. Finally, the effects of adjacent layers of different materials on the stress in epitaxial semiconductor thin films is investigated (particularly the case of InP/GaAs/Si) and discussed in conjunction with previous results.

Thermomechanical Stresses in Copper Interconnect/Low-κ Dielectric Systems

2004 ◽  
Vol 812 ◽  
Author(s):  
Y.-L. Shen ◽  
E. S. Ege
Keyword(s):  
Finite Element ◽  
Metal Oxide ◽  
Numerical Simulations ◽  
Thermal Stresses ◽  
Three Dimensional ◽  
Deformation Pattern ◽  
Barrier Layers ◽  
Copper Interconnect ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

AbstractNumerical simulations of thermal stresses in copper interconnect and low-κ dielectric systems are carried out. The analyses include two- and three-dimensional finite element modeling of the interconnect structure. Various combinations of metal, oxide and polymer-based low-κ dielectric schemes are considered in the simulation. The evolution of stresses and deformation pattern in copper, barrier layers, and the dielectrics are critically assessed.

Effects of Local Interfacial Debonding on the Stress Evolution in Aluminum Interconnects

1997 ◽  
Vol 473 ◽  
Author(s):  
Y. -L. Shen
Keyword(s):  
Thermal Stresses ◽  
Three Dimensional ◽  
Interfacial Debonding ◽  
Stress Fields ◽  
Stress Evolution ◽  
Geometrical Features ◽  
Dimensional Finite Element ◽  
Interconnect Reliability ◽  
Three Dimensional Finite Element ◽  
Aluminum Interconnects

ABSTRACTThe evolution of thermal stresses in aluminum interconnects, with the presence of local debonded areas between the aluminum line and the surrounding dielectric, is studied numerically. Local interfacial debonding is presumably due to contamination during the line patterning process. Various geometrical features of the interconnect and the debond segment are assumed, and the resulting stress fields are examined by recourse to two- and three-dimensional finite element analyses. Implications of the findings to the interconnect reliability, particularly stress-induced voiding in aluminum lines, are discussed.

Computational Models for Functionally Graded Composites Using the SMA as the Metallic Phase

2013 ◽  
Vol 470 ◽  
pp. 289-292
Author(s):  
Bing Fei Liu ◽  
Tian Lan ◽  
Pei Zhe Heng ◽  
Yu Tao Liu ◽  
Xiang Rui Liu
Keyword(s):  
Mechanical Properties ◽  
Computational Models ◽  
Thermal Loading ◽  
Metallic Phase ◽  
Functionally Graded ◽  
Stress Distributions ◽  
Graded Materials ◽  
Ceramic Phase ◽  
Temperature Resistance ◽  
New Applications

Shape Memory Alloy (SMA) composites are being used in an ever-expanding set of applications. For new applications, SMA composites are being developed as metal-ceramic Functionally Graded Materials (FGMs) utilizing SMA as the metallic phase, which contain both high temperature resistance of the ceramic phase and the mechanical properties of SMA composites. Three models including Averaging Technique of Composites (ATC), Mixture Rule (MR) and Mori-Tanaka (MT) scheme are used to calculate the stress distributions of the system subjected to thermal loading, respectively. The results obtained from the analyses of an SMA-ceramic graded composite show that after transformation the stress in the SMA composite is lower than in the case of pure elastic composite under the same thermal loading. This decrease stress can result in an increase in temperature resistance and improved mechanical properties of SMA composites. This work will be explored through a parametric study to understand their influence on SMA composite design.

Thermal Benefits of Low Solar Absorption Coating for Preventing Rail Buckling

2015 ◽  
Author(s):  
Hao Wang ◽  
Jiaqi Chen ◽  
P. N. Balaguru ◽  
Leith Al-Nazer
Keyword(s):  
Thermal Stresses ◽  
Three Dimensional ◽  
Surface Preparation ◽  
Organic Content ◽  
Coating System ◽  
Solar Absorption ◽  
Coating Application ◽  
Dimensional Finite Element ◽  
Hot Weather ◽  
Three Dimensional Finite Element

A low solar absorption coating for rail application is developed to reduce the peak rail temperature and buckling risk in summer months. The proposed coating system provides a highly reflective surface through white or off-white color and has constituents to provide high abrasion resistance and self-cleaning properties. The zero volatile organic content (VOC) and one hundred percent inorganic coating system has excellent adhesion to steel surfaces with minimal surface preparation. This paper presented the outdoor temperature monitoring results of the coated rail segments under hot weather. The results show that the application of coating could significantly reduce the peak rail temperature up to 10.5°C. Three-dimensional finite element (FE) models were developed to predict temperature distributions and thermal stresses in the rail. The thermal stress simulation shows that, when the rail neutral temperature (RNT) is relatively low, rail coating decreases the compressive stress in the rail up to about 50% during the hottest hours. Although increasing the RNT decreases compressive thermal stresses in the rail, it could increase the risk of rail break due to the increased tensile stresses in the rail. The coating application could reduce the high RNT requirement during rail placement and prevent rail buckling as the effective RNT decreases after traffic and maintenance. Therefore, the low solar absorption coating could serve as a proactive way to control peak temperatures and thermal stresses in the rail.

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