Micromechanical finite element predictions of a reduced coefficient of thermal expansion for 3D periodic architectured interpenetrating phase composites

2015 ◽  
Vol 133 ◽  
pp. 85-97 ◽  
Author(s):  
Diab W. Abueidda ◽  
Ahmed S. Dalaq ◽  
Rashid K. Abu Al-Rub ◽  
Iwona Jasiuk
Keyword(s):  
Finite Element ◽  
Thermal Expansion ◽  
Coefficient Of Thermal Expansion ◽  
Interpenetrating Phase Composites

Extraction of the Coefficient of Thermal Expansion of Thin Films from Buckled Membranes

1998 ◽  
Vol 546 ◽  
Author(s):  
V. Ziebartl ◽  
O. Paul ◽  
H. Baltes
Keyword(s):  
Thin Films ◽  
Finite Element ◽  
Thermal Expansion ◽  
Silicon Nitride ◽  
Excellent Agreement ◽  
Energy Minimization ◽  
Coefficient Of Thermal Expansion ◽  
Temperature Dependent ◽  
Minimization Method ◽  
Energy Minimization Method

AbstractWe report a new method to measure the temperature-dependent coefficient of thermal expansion α(T) of thin films. The method exploits the temperature dependent buckling of clamped square plates. This buckling was investigated numerically using an energy minimization method and finite element simulations. Both approaches show excellent agreement even far away from simple critical buckling. The numerical results were used to extract Cα(T) = α0+α1(T−T0 ) of PECVD silicon nitride between 20° and 140°C with α0 = (1.803±0.006)×10−6°C−1, α1 = (7.5±0.5)×10−9 °C−2, and T0 = 25°C.

Effect of aluminum carbide interphase on the thermomechanical behavior of carbon nanotube/aluminum nanocomposites

2018 ◽  
Vol 233 (9) ◽  
pp. 1843-1853 ◽  
Author(s):  
Xiaolong Shi ◽  
Mohammad Kazem Hassanzadeh Aghdam ◽  
Reza Ansari
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Thermal Expansion ◽  
Carbon Nanotube ◽  
Volume Fraction ◽  
Chemical Interaction ◽  
Coefficient Of Thermal Expansion ◽  
Aluminum Matrix ◽  
Aluminum Carbide ◽  
Element Method

The objective of this work is to investigate the coefficient of thermal expansion of carbon nanotube reinforced aluminum matrix nanocomposites in which aluminum carbide (Al4C3) interphase formed due to chemical interaction between the carbon nanotube and aluminum matrix is included. To this end, the micromechanical finite element method along with a representative volume element, which incorporates, carbon nanotube, interphase, and aluminum matrix is employed. The emphasis is mainly placed on the effect of Al4C3 interphase on the coefficient of thermal expansion of aluminum nanocomposites with random microstructures. The effects of interphase thickness, carbon nanotube diameter, and volume fraction on the thermomechanical response of aluminum nanocomposite are discussed. The results reveal that the effect of Al4C3 interphase on the coefficient of thermal expansion of the aluminum nanocomposites becomes more significant with (i) increasing the coefficient of thermal expansion volume fraction, (ii) decreasing the coefficient of thermal expansion diameter, and (iii) increasing the interphase thickness. It is clearly observed that the coefficient of thermal expansion varies nonlinearly with the carbon nanotube diameter; however, it decreases linearly as the carbon nanotube volume fraction increases. Furthermore, the axial and transverse coefficient of thermal expansions of aligned continuous and discontinuous carbon nanotube-reinforced aluminum nanocomposites with Al4C3 interphase are predicted. Also, the presented finite element method results are compared with the available experiment in the literature, rule of mixture, and concentric cylinder model results.

scholarly journals Thermal analysis of metal-ceramic bonding using finite element method

2014 ◽  
Vol 3 (2) ◽  
pp. 216 ◽  
Author(s):  
S. Gopinath ◽  
R Sabarish ◽  
R. Sasidharan
Keyword(s):  
Finite Element ◽  
Thermal Expansion ◽  
Thermal Stress ◽  
Bonding Strength ◽  
Coefficient Of Thermal Expansion ◽  
Linear Thermal Expansion ◽  
Processing Temperature ◽  
Element Analysis ◽  
Metal Ceramic ◽  
The Difference

This paper reports a finite element study of effect of bonding strength between metal and ceramic. The bonding strength is evaluated with different processing temperature and holding time. The difference between the coefficients of linear thermal expansion (CTEs) of the metal and ceramic induces thermal stress at the interface. The mismatch thermal stress at the interface region plays an important role in improving bonding strength. Hence, it is essential to evaluate the interface bonding in metal-ceramics joints. The Al/SiC bonding was modeled and analyzed using finite element analysis in ANSYS (v.10). Keywords: Bonding Strength, Coefficient of Thermal Expansion, Thermal Stress, Interface, Al/Sic, FEA.

Effects of Imperfections on Bifurcation of Multi-Layer Microstructures of MEMS under Thermal Loading

2007 ◽  
Vol 339 ◽  
pp. 276-280
Author(s):  
Y.T. Yu ◽  
Wei Zheng Yuan ◽  
D.Y. Qiao
Keyword(s):  
Finite Element ◽  
Thermal Expansion ◽  
Finite Element Simulation ◽  
Thermal Loading ◽  
Coefficient Of Thermal Expansion ◽  
Element Simulation ◽  
Simulation Results ◽  
Structural Bifurcation

Bifurcation of multi-layer microstructures subjected to thermal loading can be harmful for reliability and stability of MEMS structures. In this paper, three imperfections of geometry, coefficient of thermal expansion and thermal loading were introduced to investigate their effects on structural bifurcation by finite element simulation. Results show that bifurcation is strongly influenced by the imperfections. With larger deviation of imperfections, it results in a decreasing temperature to trigger the bifurcation and a gradual beginning of it.

Finite-Element Modeling and Analysis of Early-Age Cracking Risk of Cast-In-Place Concrete Culverts

2018 ◽  
Vol 2672 (27) ◽  
pp. 24-36 ◽  
Author(s):  
Yalin Liu ◽  
Anton K. Schindler ◽  
James S. Davidson
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Thermal Expansion ◽  
Lightweight Concrete ◽  
Coefficient Of Thermal Expansion ◽  
Early Age ◽  
Thermal Coefficient ◽  
Element Analysis ◽  
Joint Spacing ◽  
Cracking Risk

Extensive cracking was found in several cast-in-place concrete culverts in Alabama. This condition can decrease the long-term durability of the culverts. Early-age stress development in concrete is influenced by temperature changes, modulus of elasticity, stress relaxation, shrinkage, thermal coefficient of expansion, and the degree of restraint. The objective of this study is to determine means to mitigate early-age cracking in culverts by evaluating the cracking risk. Finite-element analysis was used to model the early-age stress by accounting for the following factors: construction sequencing, support restraint, concrete constituents, temperature effects, and the time-dependent development of mechanical properties, creep/relaxation, and drying shrinkage. Experimental results from restraint to volume change tests with rigid cracking frames were used to verify the accuracy of the finite-element analysis. A parametric study was performed to quantify the effect of changing joint spacing, joint type, construction sequence, concrete coefficient of thermal expansion, placement season, and concrete type on the risk of early-age cracking. The finite-element model results revealed that the use of the following measures will reduce the risk of early-age cracking in cast-in-place concrete culverts: concrete with lower coefficient of thermal expansion, contraction joints, sand-lightweight concrete or all-lightweight concrete, and scheduling the casting of the culvert wall to minimize the difference in its placement time relative to its previously cast base. Alternatively, to minimize the contribution of thermal effects on risk of cracking, the construction schedule should be developed to avoid concrete placement during hot weather conditions.

Design of a Composite Encapsulation for Concentrated Photovoltaic Systems With Improved Performance

2019 ◽  
Author(s):  
Kabeer Raza ◽  
Syed Sohail Akhtar ◽  
Abul Fazal M. Arif ◽  
Abbas Saeed Hakeem
Keyword(s):  
Thermal Conductivity ◽  
Finite Element ◽  
Thermal Expansion ◽  
Shear Modulus ◽  
Material Properties ◽  
Coefficient Of Thermal Expansion ◽  
Material Design ◽  
Element Model ◽  
Parametric Studies

Abstract Most of the currently used encapsulants are inefficient for cooled concentrated photovoltaic (CPV) systems. The encapsulant of cells for CPV systems, must have an optimum combination of thermal conductivity, coefficient of thermal expansion and long term shear modulus. In this work an improved backside composite encapsulation is designed and developed that can provide increased power output and longer life by enhancing the effectiveness of cooling and reducing thermal stresses. The best combination of material properties is identified through parametric studies on finite element model of CPV laminate using ethylene vinyl acetate as datum line. It is found that increasing thermal conductivity from 0.311 to 0.75 W/mK can improve the cooling and hence the power production by 2%. While long term shear modulus and coefficient of thermal expansion needs to be reduced for a longer service life. Using in-house built material design codes, optimum combinations of matrix and filler were identified that could provide the set range of properties. In line with material design code, a total of only four samples using thermoplastic polyurethane as matrix and Al2O3 or AlN as fillers were synthesized to validate the design experimentally. The material properties were measured and used in the parent finite element model to evaluate the performance of the experimentally developed material and to validate the parametric studies. A good agreement is found between the experimental and computational results and hence the overall methodology is found effective for application focused design and development of composite materials. It is expected that this material design and development approach will provide a useful guideline to the CPV manufacturing industries.

scholarly journals Thermomechanical Analysis of Ceramic Composites Using Object Oriented Finite Element Analysis

2021 ◽  
Author(s):  
Satyanarayan Patel
Keyword(s):  
Finite Element ◽  
Thermal Expansion ◽  
Coefficient Of Thermal Expansion ◽  
Object Oriented ◽  
Thermomechanical Analysis ◽  
Ceramic Composites ◽  
Thermomechanical Properties ◽  
Element Analysis ◽  
Simulation Techniques ◽  
Barrier Coating

This chapter discussed the object oriented finite element (OOF2)-based studies for ceramic composites. OOF2 is an effective method that uses an actual microstructure image of the material/composites for simulation. The effect of filler inclusions on the thermomechanical properties (coefficient of thermal expansion, thermal conductivity, Young’s modulus, stress and strain) is discussed. For this purpose, various ceramics composites (thermal barrier coating and ferroelectric based) are considered at homogeneous and heterogeneous temperature/stress conditions. The maximum stress is found at the interface of the filler/matrix due to their mismatch of thermal expansion coefficient. Further, residual and localized interface stress distributions are evaluated to analyze the composite’s failure behavior. The possible integration of OOF2 with other simulation techniques is also explored.

A Note on the Implementation of Temperature Dependent Coefficient of Thermal Expansion (CTE) in ABAQUS

1992 ◽  
Vol 114 (4) ◽  
pp. 470-472 ◽  
Author(s):  
Yi-Hsin Pao ◽  
Edward Jih ◽  
Bruce E. Artz ◽  
Larry W. Cathey
Keyword(s):  
Finite Element ◽  
Thermal Expansion ◽  
Coefficient Of Thermal Expansion ◽  
Quantitative Measure ◽  
Element Model ◽  
Electronic Packages ◽  
Not Given ◽  
Temperature Dependent ◽  
The Finite Element Model ◽  
Implementation Steps

When modeling the thermomechanical behavior of electronic packages, engineers often need to include the temperature dependence of coefficients of thermal expansion (CTE) of materials involved in the finite element model. In ABAQUS some input parameters associated with such temperature dependent CTE are not clearly defined, and directions to determine the value of these parameters are not given. Misinterpretation of these variables can result in serious errors in the finite element result. This brief tends to illustrate in detail the implementation steps of the temperature dependent CTE in ABAQUS and presents an error analysis so that a quantitative measure of the error can be obtained. The information presented here is regarded critical to those who are using ABAQUS with temperature dependent CTE.

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