scholarly journals Construction of visual 3-D fabric reinforced composite thermal performance prediction system

2019 ◽  
Vol 23 (5 Part A) ◽  
pp. 2857-2865 ◽  
Author(s):  
Shaofei Wu
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Thermal Performance ◽  
Performance Prediction ◽  
Volume Fraction ◽  
Theoretical Research ◽  
Prediction System ◽  
Reinforced Composites ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients

In view of the construction of a visualized 3-D thermal performance prediction system for fabric reinforced composites, the thermal constants analyzer was used to analyze and compare the thermal conductivity of the 3-D fabric reinforced composites by experimental methods, such as fiber volume fraction, internal braiding angle, and different yarn reduction methods and fabric structures. The factors influencing the thermal conductivity of 3-D fabric reinforced composites were studied, and the principle of thermal conductivity was analyzed. The thermal expansion coefficients of 3-D fabric reinforced composites in X- and Y-directions are one order of magnitude smaller than those in Z-directions. When aramid fabric is used as reinforcement, the composites with negative thermal expansion coefficients can be designed. The research results provide the necessary basis for the design, application and theoretical research of the 3-D fabric reinforced composites in heat conduction. Through the research of this paper, it lays a foundation for the process selection, performance design and structure optimization of this kind of material, and promotes the further application of 3-D braided composites.

An analytical approach to determine coefficients of thermal expansion of CNT/polymer nanocomposites

2020 ◽  
Vol 234 (21) ◽  
pp. 4268-4276
Author(s):  
A Abbasi ◽  
M Mondali
Keyword(s):  
Thermal Expansion ◽  
Polymer Nanocomposites ◽  
Volume Fraction ◽  
Polymer Nanocomposite ◽  
Van Der Waals Interactions ◽  
Cohesive Law ◽  
Reinforced Polymers ◽  
Interfacial Effects ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients

In this study, thermo-mechanical properties of CNT/polymer nanocomposite were investigated. Semi-continuum analytical method was used to simulate thermal behavior of CNT-reinforced polymers. CNT was modeled in an atomistic scale, whereas polymer was modeled as a continuum. Interfacial effects or the Van Der Waals interactions between matrix and CNT were simulated employing cohesive strength. The results indicate that using the cohesive law for CNT/polymer interface could provide very close results to the available experimental data. Also, adding a small quantity of CNTs to polymer leads to a slight decrease in the radial and axial thermal expansion coefficients of polymer matrix depending on temperature, volume fraction, aspect ratio, and also diameter of CNTs.

Variation of the Expansion Coefficient of Nanofluids With Temperature: A Correction for Conductivity Data

2012 ◽  
Vol 3 (4) ◽  
Author(s):  
Efstathios E. Michaelides
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Conductivity Data ◽  
Volumetric Fraction ◽  
Solid Materials ◽  
Strong Function ◽  
Temperature Changes ◽  
Thermal Expansion Coefficients ◽  
High Thermal Expansion ◽  
Expansion Coefficients

The two constituent phases of the nanofluids have thermal expansion coefficients that are significantly different. Moreover, the variability of the thermal expansion coefficients of fluids with temperature is significantly higher than that of solid materials. The mismatch of the thermal expansion coefficients creates changes of the volumetric fraction of solids with temperature changes. The changes can be significant with fluids that have high thermal expansion coefficients, such as refrigerants and fluids that operate close to their critical points. Since the thermal conductivity of nanofluids is a very strong function of the volumetric fraction of the nanoparticles, these changes of the volumetric fraction may cause significant effects on the thermal conductivity of the nanofluids, which must be accounted for in any design process.

Measurements of Thermal Properties of Gaskets for the Design of Bolted Flange Joints Under Thermal Conduction Conditions

2006 ◽  
Author(s):  
Takahiro Ohmura ◽  
Kanji Hanashima ◽  
Junichi Nyumura ◽  
Toshiyuki Sawa
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Thermal Properties ◽  
Effective Thermal Conductivity ◽  
Linear Thermal Expansion ◽  
Absolute Temperature ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients ◽  
Bolted Flange ◽  
The Relationship

In this study, the thermal properties of the gaskets, which were used for designing the bolted flange joints, such as effective thermal conductivity, specific heat, linear thermal expansion coefficient and so on were measured. Especially, the effective thermal conductivities were measured by using the heat flow method. The relationship between the gasket structure and the thickness was shown by using an equivalent thermal resistance, and an empirical equation of effective thermal conductivity, which was related to the bulk density and absolute temperature, was proposed by deriving the heat conduction in solid, radiation and gas. Also, in the measurement of the linear thermal expansion coefficients of the gaskets, the measured values were shown to change substantially below 150 °C, and to depend on the heating rate and the load applied on the gasket sample.

Thermophysical Properties of Gd2O3 Doped SrHfO3 Ceramic

2015 ◽  
Vol 816 ◽  
pp. 237-241 ◽  
Author(s):  
Wen Ma ◽  
Yi Ren ◽  
Xi Long Jin ◽  
Ya Hong Liang ◽  
Bao Dong Chen ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Phase Transitions ◽  
High Temperature ◽  
Solid State ◽  
Solid State Reaction Method ◽  
Reaction Method ◽  
Long Period ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients

Gd2O3 (10mol%) doped SrHfO3 (Sr (Hf0.9Gd0.1)O2.95) was synthesized by solid state reaction method. The phase stability of the synthesized Sr (Hf0.9Gd0.1)O2.95 powder at high temperature of 1450 oC for a long period and in a temperature range of RT-1400 oC was characterized by XRD and DSC, respectively. The thermal expansion coefficients (TECs) of bulk Sr (Hf0.9Gd0.1)O2.95 were recorded by a high-temperature dilatometer, indicating that the phase transitions of SrHfO3 are suppressed remarkably by doping Gd2O3. The thermal conductivity of bulk Sr (Hf0.9Gd0.1)O2.95 at 1000 oC is ~1.95 W/m·K, which is ~11% lower than that of bulk 8YSZ.

scholarly journals Polytope Sector-Based Synthesis and Analysis of Microarchitectured Materials With Tunable Thermal Conductivity and Expansion

2015 ◽  
Author(s):  
Jonathan B. Hopkins ◽  
Howon Lee ◽  
Nicholas X. Fang ◽  
Christopher M. Spadaccini
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Material Property ◽  
Analytical Methods ◽  
Positive Zero ◽  
Bulk Property ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients ◽  
Projection Microstereolithography ◽  
2D And 3D

The aim of this paper is to (1) introduce an approach, called Polytope Sector-based Synthesis, for synthesizing 2D or 3D microstructural architectures that exhibit a desired bulk-property directionality (e.g., isotropic, cubic, orthotropic, etc.), and (2) provide general analytical methods that can be used to rapidly optimize the geometric parameters of these architectures such that they achieve a desired combination of bulk thermal conductivity and thermal expansion properties. Although the methods introduced can be applied to general beam-based microstructural architectures, we demonstrate their utility in the context of an architecture that can be tuned to achieve a large range of extreme thermal expansion coefficients — positive, zero, and negative. The material-property-combination region that can be achieved by this architecture is determined within an Ashby-material-property plot of thermal expansion vs. thermal conductivity using the analytical methods introduced. Both 2D and 3D versions of the design have been fabricated using projection microstereolithography.

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