scholarly journals STUDY OF THE EFFECT OF COMPLEX-COMPOSITE STRUCTURES ON THE THERMAL CHARACTERISTICS OF THE POLYMER ADDITIVE MATERIALS

2019 ◽  
Vol 45 (4) ◽  
pp. 8-17
Author(s):  
N. V. Bekrenev ◽  
V. M. Makarova ◽  
S. P. Pavlov
Keyword(s):  
Thermal Conductivity ◽  
Composite Material ◽  
Carbon Fibers ◽  
Composite Structures ◽  
Complex Shape ◽  
Experimental Studies ◽  
Thermal Characteristics ◽  
Additive Technologies ◽  
Mechanical And Thermal Properties ◽  
Additive Materials

Objectives The use of additive technologies is one of the promising areas for improving the production of products for various purposes in the transition to a digital economy. Method. Layered construction of objects of complex shape in accordance with the developed solid-state model from materials with different mechanical and thermal properties allows directionally controlling the distribution of various components in the volume of the composite material and forming topological structures that provide a rational balance between various performance characteristics and reliability of the product. Result. Based on experimental studies, it has been established that reinforcing topological reinforcement of 3D printing objects made from ABS plastic with a composite consisting of carbon fibers and ED-20 epoxy resin, along with an increase in flexural strength and tensile strength, contributes to an increase in thermal conductivity of the material by more than 18% and thermal diffusivity - by 20%. A computer simulation of elementary cells of a composite material consisting of a polymer matrix, carbon fiber and special core inclusions with high thermal conductivity was performed, which made it possible to further increase thermal conductivity depending on the relative fiber diameter and the percentage of the additional component in an amount from 46 to 75%. Conclusion It is shown that additive technologies are an effective tool for creating universal topologies that allow technologically managing a combination of both mechanical and thermophysical properties of structural materials by determining the rational relative position of their components depending on the purpose and level of achievement of the required characteristics. 

scholarly journals Study the Effect of Different Percentages of Natural (Orange Peels and Date Seeds) and Industrial Materials (Carbon and Silica) on the Mechanical and Thermal Properties of Polymeric Reinforced Composites

2018 ◽  
Vol 14 (4) ◽  
pp. 16-23
Author(s):  
Haydar Abed Dahad ◽  
Sameh Fareed Hasan ◽  
Ali Hussein Alwan
Keyword(s):  
Thermal Conductivity ◽  
Composite Material ◽  
Thermal Properties ◽  
Young’S Modulus ◽  
Weight Ratio ◽  
Mechanical And Thermal Properties ◽  
Orange Peels ◽  
Industrial Materials ◽  
Flexural Tests ◽  
Natural Composite

Mechanical and thermal properties of composites, consisted of unsaturated polyester resin, reinforced by different kinds of natural materials (Orange peels and Date seeds) and industrial materials (carbon and silica) with particle size 98 µm were studied. Various weight ratios, 5, 10, and 15 wt. % of natural and industrial materials have been infused into polyester. Tensile, three-point bending and thermal conductivity tests were conducted for the unfilled polyester, natural and industrial composite to identify the weight ratio effect on the properties of materials. The results indicated that when the weight ratio for polyester with date seeds increased from 10% to 15%, the maximum Young’s modulus decreased by 54%. When the weight ratio was 5%, the maximum Young’s modulus, yield stress and ultimate tensile stress occurred in the polyester with date seeds. The results of tensile and flexural tests showed that the natural composite material has a higher strength than the industrial material. While the results of flexural tests manifested that the maximum improvement in the flexural strength is obtained for orange peels at 5 wt. %, where the maximum increasing percentage is 153.4% than pure polyester. The thermal conductivity of orange peels decreased to the half value when the weight ratio increased from 10% to 15%. The thermal conductivity for polyester with orange peels was greater than the thermal conductivity of polyester with date seeds with maximum percentage occurred at weight ratio 10% is 14.4%, but the thermal conductivity of the industrial composite material was higher than the natural composite material. Finally, the date seeds composite was a good insulator and it had a reduced heat transfer rate in comparison to the rest of the samples, also the maximum variation of temperature with time occurred in date seeds composite.

scholarly journals Composite material based on an ablative phenolic resin and carbon fibers

2009 ◽  
Vol 74 (4) ◽  
pp. 441-453 ◽  
Author(s):  
Vineta Srebrenkoska ◽  
Gordana Bogoeva-Gaceva ◽  
Dimko Dimeski
Keyword(s):  
Mechanical Properties ◽  
Composite Material ◽  
High Temperature ◽  
Carbon Fibers ◽  
Mechanical And Thermal Properties ◽  
High Temperature Application ◽  
Molding Process ◽  
Molding Compound ◽  
Temperature Application ◽  
Fiber Matrix

In this study, a technological procedure for the production of a molding compound based on short carbon fibers and an ablative phenol-formaldehyde resin for high temperature application was optimized. The starting raw materials were characterized and molding compounds with different fiber/ /matrix ratios and different fiber lengths were obtained. From the different laboratory samples, molded parts were made by thermo-compression. The basic mechanical and thermal properties of the composites were determined. From the obtained results, the optimal fiber/matrix ratio was determined for a production of molding compound for high temperature application. The molding process of the composite material was optimized and all the parameters for good mechanical properties and high thermal stability of the composite were obtained. Optimization of the composite molding process was performed by the application of a numerical method for a planned experiment, i.e., a full three-factorial experimental design with variance of all three parameters (fiber length, temperature and time of the press cycle) on two levels. The obtained mechanical properties (flexural strength: 247 MPa, modulus: 27.6 GPa, impact resistance: 110 (for test moldings 10 mm?10 mm) and 91 kJ/m2 (for test moldings 15 mm?15 mm)) justified the application of this composite material in the automotive, leisure, military and other industries where high temperature resistance and high mechanical strength is required.

EXPERIMENTAL INVESTIGATIONS OF ULTRASONIC THERMAL TOMOGRAPHY(US THERMOTOMOGRAPHY) OF COMPOSITE MATERIALS

2019 ◽  
pp. 58-62
Author(s):  
O. N. Budadin ◽  
E. S. Vyachkin ◽  
E. A. Vyachkina ◽  
V. O. Kaledin ◽  
S. O. Kozelskaya
Keyword(s):  
Composite Material ◽  
Heat Source ◽  
Composite Structures ◽  
Experimental Studies ◽  
Internal Heat ◽  
Internal Heat Source ◽  
Temperature Fields ◽  
Internal Defects ◽  
Nickel Chromium ◽  
Thermal Tomography

Analysis of internal defects in the structure of composite objects can be based on the study of dynamic temperature fields, the patterns of variation of which reflect the location of heat sources. For example, acoustic ones, under external influences, determination of the location of thermal field sources (internal defects) – thermal tomography – presents in this approach, in general, the problem of identifying the model of heat propagation in a plate. This paper describes a method and technical means for determining the depth of occurrence of internal defects in composite structures by analyzing the temperature fields on two surfaces of a product to be created by an internal heat source, which is a defect, and by formed mechanical action on it, for example, ultrasonic mechanical vibrations (ultrasonic thermotomography). Experimental studies of the previously theoretically proved method of thermal tomography in the presence of an internal heat source have been carried out. As a research object, a plate of composite material – pressed fabric-based laminate- was considered. To simplify the experimental studies and increase the reliability of the results, the internal heat source was modeled with a nickel-chromium spiral to be heated by an electric current. The nickel-chromium spiral was laid in the plates when their pressing (manufacturing) at various occurence depths relative to surfaces of the plates. The experimental investigation technique is described. It is experimentally shown that the proposed method allows the occurence depth of defects in a composite material to be determined. Fault in the depth determining of the defects occurrence depends on the depth value and does not exceed 10 % of the thickness of the controlled article that is acceptable for the practical use.

Thermal conductivity of biomimetic leaf composite

2017 ◽  
Vol 52 (13) ◽  
pp. 1737-1746 ◽  
Author(s):  
G Liu ◽  
R Ghosh ◽  
D Mousanezhad ◽  
A Vaziri ◽  
H Nayeb-Hashemi
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Composite Structures ◽  
Volume Fraction ◽  
Cell Structure ◽  
Matrix Material ◽  
Mechanical And Thermal Properties ◽  
Ceramic Fibers ◽  
Fiber Morphology ◽  
Fiber Volume

The venous morphology of a typical plant leaf affects its mechanical and thermal properties. Such a material could be considered as a fiber reinforced composite structure where the veins and the rest of the leaf are considered as two materials having highly contrast mechanical and thermal properties. The variegated venations found in nature is idealized into three principal fibers—the central mid-fiber corresponding to the mid-rib, straight parallel secondary fibers attached to the mid-fiber representing the secondary veins, and then another set of parallel fibers emanating from the secondary fibers mimicking the tertiary veins of a typical leaf. This paper addresses the in-plane thermal conductivity of such a composite by considering such a venous fiber morphology embedded in a matrix material. We have considered two cases, fibers having either higher or lower conductivity respect to the matrix. The tertiary fibers do not interconnect the secondary fibers in our present study. We carry out finite element based computational investigation of the thermal conductivity of these composites under uniaxial thermal gradients and study the effect of different fiber architectures. To this end, we use two broad types of architectures both having similar central main fiber but differing in either having only secondary fibers or additional tertiary fibers. The fiber and matrix volume fractions are kept constant and a comparative parametric study is carried out by varying the inclination of the secondary fibers. We find the heat conductivity in the direction of the main fiber (Y direction) increases significantly as the fiber angle of the secondary increases. Furthermore, for composite with metal fibers, the conductivity in the Y direction is further enhanced when composite is manufactured by having secondary fibers forming a closed cell structure. However, for composite with ceramic fibers, the conductivity of the composite in the Y direction is little affected by having secondary fibers closed. An opposite behavior is observed when considering conductivity of the composite in the X direction. The conductivity of the composite in the X direction is reduced with increase in the angle of the secondary fibers. Higher conductivity in the X direction is achieved for composite with no closed cells for composites with metal fibers. The results also indicate that for composites with the constant fiber volume fraction, morphology of tertiary fibers may not significantly alter material conductivities. In conclusion, introducing a leaf-mimicking topology in fiber architecture can provide significant additional degrees of tunability in design of these composite structures.

scholarly journals Bending Response of Composite Material Plates with Specific Properties, Case of a Typical FGM "Ceramic/Metal" in Thermal Environments

2018 ◽  
Author(s):  
Abdelrahmane Bekaddour Benyamina ◽  
Bachir Bouderba ◽  
Abdelkader Saoula
Keyword(s):  
Composite Material ◽  
Composite Structures ◽  
Structural Engineering ◽  
Rapid Development ◽  
Functionally Graded ◽  
Mechanical And Thermal Properties ◽  
Graded Materials ◽  
Thermal Environments ◽  
Shear Function ◽  
Electronic Chemical

The rapid development of composite materials and structures in recent years has attracted the increased attention of many engineers and researchers. These materials are widely used in aerospace, military, mechanical, nuclear, marine, optical, electronic, chemical, biomedical, energy sources, automotive fields, ship building and structural engineering industries. In conventional laminate composite structures, homogeneous elastic plate are bonded together to obtain improved mechanical and thermal properties. However, the abrupt change in material properties across the interface between the different materials can cause strong inter-laminar stresses leading to delamination, cracking, and other damage mechanisms at the interface between the layers. To remedy these defects, functionally graded materials (FGM) are used, in which the properties of materials vary constantly. The purpose of this paper is to analyze the thermomechanical bending behavior of functionally graded thick plates (FGM) made in ceramic/metal. This work presents a model that employed a new transverse shear function. The numerical results obtained by the present analysis are presented and compared with those available in the literature (classical, first-order, and other higher-order theories). It can be concluded that this theory is effective and simple for the static analysis of composite material plates with specific properties "Case of a typical FGM (ceramic/metal)" in thermal environments.

Preparation of Carbon Fiber Reinforced Metakaolin Based-Geopolymer Foams

2018 ◽  
Vol 766 ◽  
pp. 19-27 ◽  
Author(s):  
Ju Hak Lee ◽  
Suthee Wattanasiriwech ◽  
Darunee Wattanasiriwech
Keyword(s):  
Thermal Conductivity ◽  
Carbon Fiber ◽  
Carbon Fibers ◽  
Treatment Time ◽  
Mechanical And Thermal Properties ◽  
Pore Former ◽  
Oxidation Treatment ◽  
Thermal Insulating ◽  
Significant Difference ◽  
The Matrix

In this report, metakaolin based-geopolymer foams reinforced with carbon fibers have been prepared for thermal insulating purpose. Potassium silicate and potassium hydroxide solutions were used as activating agents while hydrogen peroxide was used as a pore former. In order to improve chemical interfacial adhesion with the matrix, the carbon fiber was pre-oxidized using 3 M of nitric acid solution for 10, 30, 50 and 70 min. It was found that variation in treatment time did not cause significant difference in neither mechanical nor thermal conductivity. However, both flexural strength and fracture toughness were significantly improved when the geopolymer foams were reinforced with carbon fibers while thermal conductivity was increased by about two times. The prepared geopolymer foams showed promising results to serve the designed purpose. Keywords: metakaolin based-geopolymer foam, carbon fiber reinforcement, oxidation treatment, mechanical and thermal properties.

scholarly journals Thermal Conductivity of CNT - Wated Nanofluids: a Review

2020 ◽  
Vol 22 (1) ◽  
pp. 207-220 ◽  
Author(s):  
M. Akhilesh ◽  
K. Santarao ◽  
M. V. S. Babu
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Experimental Studies ◽  
Thermal Characteristics ◽  
Thermal Conducting ◽  
The Stability ◽  
Proper Group ◽  
Physical Stabilization ◽  
Transportation Applications

AbstractIn heat transportation applications, water is most commonly used fluid. The efficiency of equipment used in these applications depends on thermal characteristics of water used. The thermal characteristics of water could be upgraded by suspending high thermal conducting solid nanoparticles. In this paper an attempt has been made to know how the use of surfactants and functionalization of carbon nanotube walls can affect the thermal characteristics and stability of nanofluid. A thorough analysis of collected literature revealed that carbon nanotubes have much higher thermal conductivity than any other nanoparticles and hence improve the thermal properties of water when suspended in them. Further it is concluded that suspension of carbon nanotubes in water requires use of surfactant or functionalization of carbon nanotube walls with proper group. By setting optimum pH and better dispersion, better thermal conductivity is possible. Experimental studies in the literature survey reveal that chemical stabilization techniques and physical stabilization techniques together decide the stability of the nanofluid.

The system of indicators of the quality of the carbon-carbon composite materials and technologies of their production

2018 ◽  
pp. 127-132
Author(s):  
T. N. Antipova ◽  
D. S. Shiroyan
Keyword(s):  
Composite Material ◽  
Low Cost ◽  
Experimental Studies ◽  
Carbon Matrix ◽  
Carbon Composite ◽  
Optimal Number ◽  
Laboratory Equipment ◽  
Carbon Composite Material ◽  
Carbon Composite Materials

The system of indicators of quality of carbon-carbon composite material and technological operations of its production is proved in the work. As a result of the experimental studies, with respect to the existing laboratory equipment, the optimal number of cycles of saturation of the reinforcing frame with a carbon matrix is determined. It was found that to obtain a carbon-carbon composite material with a low cost and the required quality indicators, it is necessary to introduce additional parameters of the pitch melt at the impregnation stage.

Promising hybrid fabrics based on carbon and aramid fibers as a reinforcing filler for polymer composites

2019 ◽  
pp. 86-95 ◽  
Author(s):  
G. F. Zhelezina ◽  
V. G. Bova ◽  
S. I. Voinov ◽  
A. Ch. Kan
Keyword(s):  
Composite Material ◽  
Polymer Composites ◽  
Carbon Fibers ◽  
Mechanical Characteristics ◽  
High Strength ◽  
High Modulus ◽  
Hybrid Composite Material ◽  
Hybrid Fabric ◽  
Reinforcing Filler ◽  
Physical And Mechanical Characteristics

The paper considers possibilities of using a hybrid fabric made of high-modulus carbon yarn brand ZhGV and high-strength aramid yarns brand Rusar-NT for polymer composites reinforcement. The results of studies of the physical and mechanical characteristics of hybrid composite material and values of the implementation of the strength and elasticity carbon fibers and aramid module for composite material are presented. 

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