scholarly journals The Strength and Delamination of Graphene/Cu Composites with Different Cu Thicknesses

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2983
Author(s):  
Song-Mi Kim ◽  
Woo-Rim Park ◽  
Oh-Heon Kwon
Keyword(s):  
Fracture Behavior ◽  
Mechanical Characteristics ◽  
Volume Fraction ◽  
Composite Model ◽  
Analytical Models ◽  
Thickness Variation ◽  
Evaluation Standards ◽  
Delamination Fracture ◽  
Tensile Forces ◽  
And Performance

This study analyzed the mechanical and fracture behavior of graphene/copper (Cu) composites with different Cu thicknesses by using molecular dynamics (MD) and representative volume element (RVE) analysis. Three graphene/Cu composite analytical models were classified as 4.8, 9.8, and 14.3 nm according to Cu thicknesses. Using MD analysis, zigzag-, armchair-, and z (thickness)-direction tensile analyses were performed for each model to analyze the effect of Cu thickness variation on graphene/Cu composite strength and delamination fracture. In the RVE analysis, the mechanical characteristics of the interface between graphene and Cu were evaluated by setting the volume fraction to 1.39, 2.04, and 4.16% of the graphene/Cu composite model, classified according to the Cu thickness. From their obtained results, whether the graphene bond is maintained has the greatest effect on the strength of graphene/Cu composites, regardless of the Cu thickness. Additionally, graphene/Cu composites are more vulnerable to armchair direction tensile forces with fracture strengths of 14.7, 8.9, and 8.2 GPa depending on the Cu thickness. The results of this study will contribute to the development of guidelines and performance evaluation standards for graphene/Cu composites.

Characterization of a soft magnetic composite for use in road-embedded wireless-charging systems

2021 ◽  
pp. 1-10
Author(s):  
Kai-Yeung Li ◽  
Bill Trompetter ◽  
Maedeh Amirpour ◽  
Tom Allen ◽  
Simon Bickerton ◽  
...  
Keyword(s):  
Volume Fraction ◽  
Flexural Modulus ◽  
Magnetic Core ◽  
Analytical Models ◽  
Magnetic Composite ◽  
Wireless Charging ◽  
Soft Magnetic ◽  
Soft Magnetic Composite ◽  
Trade Offs ◽  
Wheel Loading

The ferrite magnetic core is an integral component of road-embedded wireless charging systems for electric vehicles. However, the brittleness of ferrite makes it susceptible to premature fracture due to cyclic wheel loading from vehicles. This has motivated the development of a soft magnetic composite (SMC) composed of a flexible polyurethane and crushed ferrite as an alternative. An experimental investigation was conducted into the trade-offs between mechanical, thermal and magnetic properties at ferrite volume fractions between 45.9[Formula: see text]vol% and 80.6[Formula: see text]vol%. A comparison was made between measured properties and predictions from analytical models in order to further investigate the characteristics of the composite. The investigation showed a trade-off between the increase in magnetic permeability and the reduction in strain-to-failure as ferrite volume fraction increased. In addition, a large increase in flexural modulus and thermal conductivity, along with a slight increase in flexural strength was observed. More importantly, the strain-to-failure of the composite was 20 times higher than that of ferrite even at the highest volume fraction, indicating that the SMC was successful in providing a more ductile and flexible alternative.

scholarly journals Comparison of Analytical Approaches Predicting the Compressive Strength of Fibre Reinforced Polymers

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2517 ◽  
Author(s):  
Christian Leopold ◽  
Sergej Harder ◽  
Timo Philipkowski ◽  
Wilfried Liebig ◽  
Bodo Fiedler
Keyword(s):  
Compressive Strength ◽  
Prediction Accuracy ◽  
Volume Fraction ◽  
Fibre Volume Fraction ◽  
Experimental Results ◽  
Analytical Models ◽  
Reinforced Polymers ◽  
Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Analytical Approaches

Common analytical models to predict the unidirectional compressive strength of fibre reinforced polymers are analysed in terms of their accuracy. Several tests were performed to determine parameters for the models and the compressive strength of carbon fibre reinforced polymer (CFRP) and glass fibre reinforced polymer (GFRP). The analytical models are validated for composites with glass and carbon fibres by using the same epoxy matrix system in order to examine whether different fibre types are taken into account. The variation in fibre diameter is smaller for CFRP. The experimental results show that CFRP has about 50% higher compressive strength than GFRP. The models exhibit significantly different results. In general, the analytical models are more precise for CFRP. Only one fibre kinking model’s prediction is in good agreement with the experimental results. This is in contrast to previous findings, where a combined modes model achieves the best prediction accuracy. However, in the original form, the combined modes model is not able to predict the compressive strength for GFRP and was adapted to address this issue. The fibre volume fraction is found to determine the dominating failure mechanisms under compression and thus has a high influence on the prediction accuracy of the various models.

STUDYING THE EFFECT OF DIFFERENT ADDITIVES ON THE THERMAL CONDUCTIVITY AND MECHANICAL CHARACTERISTICS OF EPOXY-BASED COMPOSITE MATERIALS

2021 ◽  
Vol 25 (Special) ◽  
pp. 2-72-2-77
Author(s):  
Hassanein M. Nhoo ◽  
◽  
Raad. M. Fenjan ◽  
Ahmed A. Ayash ◽  
◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Particle Size ◽  
Tensile Strength ◽  
Mechanical Characteristics ◽  
Volume Fraction ◽  
Pyrolysis Process ◽  
Volume Percent ◽  
Fair Comparison ◽  
Filler Level

The current paper deals with investigating the effect of two different fillers on the thermal and mechanical characteristics of epoxy-based composite. The filler used throughout the study are: charcoal and Pyrex, both of them are different in nature and have not been investigated thoroughly or even compared fairly in terms of their effect on polymer matrix. Further, they can be considered as a cheap filler, charcoal can be obtained from a simple pyrolysis process of plants (charcoal) and Pyrex waste can be collected easily. Both types are added to the selected matrix with volume percent ranged from 10 to 60 with increments of 10. To ensure a fair comparison, the particle size is fixed (is about 1.7 micrometer). The results showed that the epoxy thermal conductivity has enhanced by about two orders of magnitudes over the studied range of filler. In terms of mechanical properties, the charcoal improves the tensile strength about 84% at 60% volume fraction while the Pyrex effect is about 40% at the same filler level. On the contrast, the results of compressive strength do not show an appreciable improvement overall. It decreases by about 12% at 60% volume fraction of charcoal while increases about the same percent with Pyrex at the same filler level.

scholarly journals The field of rational application of the methods of hardening treatment

2018 ◽  
Vol 224 ◽  
pp. 01061
Author(s):  
Vitalii Krutsilo ◽  
Nina Papsheva ◽  
Olga Akushskaya
Keyword(s):  
Surface Layer ◽  
Titanium Alloys ◽  
Performance Indicators ◽  
Mechanical Characteristics ◽  
Extreme Conditions ◽  
Rational Application ◽  
Hardening Treatment ◽  
And Performance

The paper presents data on the research of influence of various methods of hardening on physico- mechanical characteristics of surface layer and performance indicators of details from heatproof, difficult-to-cut steels and titanium alloys working in extreme conditions.

scholarly journals Heat Transfer Enhancement of TiO2/Water Nanofluids Flowing Inside a Square Minichannel with a Microfin Structure: A Numerical Investigation

Energies ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 3041 ◽  
Author(s):  
Budi Kristiawan ◽  
Agung Tri Wijayanta ◽  
Koji Enoki ◽  
Takahiko Miyazaki ◽  
Muhammad Aziz
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Volume Fraction ◽  
Practical Application ◽  
Transfer Enhancement ◽  
Working Fluids ◽  
Performance Evaluation Criterion ◽  
Developing Flow ◽  
And Performance ◽  
Economic Considerations

A combination of two passive heat transfer enhancement techniques using a microfin structure and nanofluids was investigated numerically. TiO2/water nanofluids flowing inside a square minichannel with a microfin structure (SMM) were observed as a practical application. Increased heat transfer performance was investigated by observing the Nusselt number, friction factor, and performance evaluation criterion (PEC). Velocity and temperature profiles were also demonstrated at a laminar developing flow regime. The SMM used in this work had six microfins (N = 6) and TiO2/water nanofluids with various nanoparticle concentrations of 0.005, 0.01, and 0.1 vol.%. By combining nanofluids as working fluids and SMM as a passive heat transfer enhancement, the maximum PEC value of 1.2 was achieved at Re = 380 with a volume fraction of 0.01 vol.%. It is obvious that compared to water flowing inside the square minichannel microfin, the heat transfer can be increased by using only a nanofluid with a volume fraction of 0.01%. The combination of a microfin and nanofluids as working fluids is strongly recommended due to its excellent performance in terms of heat transfer and economic considerations.

Numerical and Experimental Assessment of the Highway Arch Viaduct

2015 ◽  
Vol 769 ◽  
pp. 252-259
Author(s):  
Jan Bencat ◽  
Maria Stehlikova ◽  
Milan Skarupa
Keyword(s):  
Dynamic Testing ◽  
Highway Bridges ◽  
Structural Condition ◽  
Traffic Load ◽  
Analytical Models ◽  
Mode Shapes ◽  
Bridge Structure ◽  
Modal Damping ◽  
Bridge Structures ◽  
And Performance

Full–scale dynamic testing of bridge structures can provide valuable information on the service behavior and performance of structures. With the growing interest in the structural condition of highway bridges, dynamic testing can be used as a tool for assessing the integrity of bridges. From the measured dynamic response, induced by instructed passing trucks, modal parameters (natural frequencies, mode shapes and modal damping values) and system parameters (stiffness, mass and damping matrices) are obtained. These identified parameters can then be used to characterize and monitor the service of the bridge structure in the future. Analytical models of the structure can also be validated using these parameters [1,2]. The paper presents a procedure for estimating the traffic load bearing capacity of the steel arch highway viaduct Bridge Structure 205 (DC1–9, 755 m) constructed on Highway D1 in Nord Slovakia (Fig. 1) over the natural hollow basin via dynamic tests of the viaduct structures.

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