Modern Composite Materials Research Articles

ENERGY EFFICIENT DESALINATOR

Objectives The aim of the research was the development of an ultrasonic generator of technological design with a wide frequency range of output voltage. Methods The prototype works were performed and the functional scheme of the multifrequency ultrasonic generator realised in the experimental sample was developed, as well as the design of an ultrasonic piezoceramic system capable of operating at two resonant frequencies of 22 and 44 kHz. Results Based on the feature analysis of the modern composite material structure and technologies for moulding products, it was found to be expedient to introduce ultrasonic impregnation into the technological process, which can ensure increased uniformity in filling the structure with a binder as well as greater homogeneity of physicomechanical characteristics. A schema for the ultrasonic generator built into the technological equipment is developed, providing the formation of harmonic signals with a frequency alternating from 20 to 60 kHz, and power adjustable from 100 to 500 W, which will allow the implementation of highperformance ultrasonic technologies for processing materials with a heterogeneous structure formed during the manufacturing process. The studies were carried out according to parametric optimisation of the converter taking into account the specific load types. A special feature of the generator's power supply is its versatility in terms of frequency and voltage ranges, as well as the required quality indicators of the energy generated. The generator allows the reference frequency to be programmed using a laptop and then fine-tuned from the control panel in resonance with the radiator with a resolution of 10 Hz directly. The built-in microprocessor allows the reference frequency entered from the laptop to be stored in the memory. Conclusion The use of multifrequency ultrasonic sources allows the acting parameters to be optimised for ultrasonic impregnation of fibre-reinforced composite materials as well as their finishing dimensional processing, depending on the density of the structure and the reinforcement scheme used.

Calculation investigation of the strength of the composite wheel rim

The aim of the research is to reduce the unsprung mass, the moment of inertia of the racing automobile’s wheel while maintaining the necessary strength due to the using of composite materials in its construction. Currently, the composite materials have been obtained a widespread usage as structural materials in the automobile assemblies and units. Particularly, the using of modern composite materials in the transmission elements of the automobile, such as drive shafts, axle shafts or wheels, makes it possible to substantially improve the performances of the wheeled vehicle: reduce the full and the unsprung weight. It is possible to point out from the modern composite materials, the polymeric composite materials having carbon fibers as a reinforcing element, which are possessing a low density and the best combining a high level of specific strength with producibility of the products. The object of the research is the racing automobile’s wheel which belongs to the class of “Formula Student”. The usage of composite materials in the construction of similar wheels, as well as the estimated evaluation of the wheel’s strength during its manufacturing from composite materials are discussed. The regulations of the competitions permit a great freedom in choosing the wheel construction. The estimated strength evaluation was carried out by the finite element method, the original finite element wheel model was developed for this purpose taking into account the anisotropic properties of the reinforced materials. The computational investigation of the strength of the selected construction showed that the rim which is made of the composite material has an excessive safety factor at the design loads. The proposed constructive decision allows to reduce the wheel weight by 33% (up to 1.68 kg) in comparison with the one-piece wheel made of magnesium alloys (2.5 kg).

The choice of iron-containing filling for composite radioprotective material

The paper presents the data the composition of modern composite building materials including materials which in addition to high physical-mechanical have radio-protective properties. The article presents infrared researches and differential thermal data of fine-grained magnetite and hematite beneficiated iron-ore concentrates. The choice of the most suitable filling for new composite radio-protective building material engineering and development was made basing on the magnetite and hematite data presented in the paper.

Overflowing phreatic dams built with the use of modern composite materials

Costs and terms of hydroelectric complexes construction, of low pressure constructions in particular, can be significantly reduced by ensuring the safe passage of flood discharge through the crest of water-retaining structures. When water-retaining structures are made from soils, this condition can only be fulfilled by creating special fastenings of a crest and dam slopes from erosion. There is a large number of technical solutions for overflowing phreatic dams construction with the use of stone, concrete, reinforced concrete and metal. However, most of them have specific disadvantages. They are high materials consumption, labour input and expenses. These disadvantages, in our opinion, can be minimized by applying modern composite materials such as geosynthetic shells, concrete-filled textile floor-floor-mats and coarse-pored concrete. The paper describes structures of overflowing phreatic dams invented by the authors with the use of modern composite materials, as well as the results of model hydraulic studies of overflowing phreatic dams with a downstream slopes formed by geosynthetic shells.

The Design and Construction Process of a Test Stand for Casting the Power Steering’S Housing with the Use of the Pdcpd Material

The use of new technologies and materials in various industries is a natural process that is directly related to the very high rate of development of these technologies. Certain industries decide to much faster introduce new technologies and materials. One of such branches is the automotive industry, whose representatives are very energetically looking for both financial savings and savings resulting from the vehicles mass reduction. An economically justified approach to construction materials is leading the search for new solutions and materials. The use of a modern material such as the two-component PDCPD composite shows hitherto unknown possibilities of producing subassemblies of many different constructions. The possibility of using a modern composite material with parameters comparable to that of metals and significantly lighter, can be an excellent alternative in the selection of materials for many parts of motor vehicles. The potentiality of precise casting of tolerated surfaces will allow to reduce the operations related to machining process, which is an indispensable part of the production process of elements that are cast of metal. This article describes the process of designing and building a test stand for precise positioning of power steering gear components at the stage of casting their housing. The article presents the principle of operation of the test stand and the process of preparation for the casting and the cast itself will be rudely described. Due to the implementation of research as part of a research project with an industrial partner, the article will only describe some operations. This is related to the confidentiality of the project.

Taguchi analysis of tool wear and delamination in milling of GFRP composite using coated K10 end mill

Modern composite materials constitute a significant proportion of the engineered materials market ranging from everyday products to sophisticated niche applications. While composites have already proven their worth as weight -saving materials, the current challenge is to make them machinable with minimum tool wear. In this study an attempt has been made to fabricate Glass fibre reinforced composites using hand moulding techniques and test its machinability based on delamination and tool wear using Ti-Nimate Coated Carbide and Ti-Carbonitride K10 end mill. The experiment was conducted in Vertical Machining Centre using Taguchi L8 orthogonal array. The test results showed that Ti-Carbonitride causes less damage to material during milling of glass fibre reinforced plastics (GFRP), whereas Ti-Nimate Coated Carbide has less tool wear at high speed, feed and depth of cut.

Enhancing the Compressive Strength and Density of Cement Mortar by the Addition of Different Alignments of Glass Fibers and Styrene Butadiene Rubber

Abstract
 In the field of construction materials the glass reinforced mortar and Styrene Butadiene mortar are modern composite materials. This study experimentally investigated the effect of addition of randomly dispersed glass fibers and layered glass fibers on density and compressive strength of mortar with and without the presence of Styrene Butadiene Rubber (SBR). Mixtures of 1:2 cement/sand ratio and 0.5 water/cement ratio were prepared for making mortar. The glass fibers were added by two manners, layers and random with weight percentages of (0.54, 0.76, 1.1 and 1.42). The specimens were divided into two series: glass-fiber reinforced mortar without SBR and glass-fiber reinforced mortar with 7% SBR of mixture water. All specimens were tested after curing for 7 and 28 days, glass-fiber reinforced mortar exhibited better properties than control mortar in improvement of compressive strength and lowering the density after curing for 28 days due to the completion of cement hydration reaction.. For compressive strength the best results were achieved with 1.42 wt.% layers glass-fiber reinforced mortar with 7% SBR which gave 41.56 MPa. On the other hand, the addition of 1.42 wt.% random glass-fiber without SBR addition caused the beast reduction in density by 10.6% and produced lighter structure than control sample.
 Keywords: Random glass fibers , Glass fibers layers, SBR, compressive strength, density.

Application of ultrasonic guided waves for non-destructive testing of large and complex geometry engineering structures

The wide group of large engineering constructions made from welded metal components and modern composite materials during daily exploitation under non-stationary loads, continuous influence of vibrations and complicated environmental conditions have demand of periodical tests in order to avoid appearance and evolution of the defects. All of them have one common feature – large areas to be tested and the complex geometry. The objective is to improve air-coupled and contact type testing techniques for excitation and reception of appropriate modes of ultrasonic guided waves in large and complex structures. Also, to develop inspection techniques which enable to detect required types of internal defects. The air-coupled and contact ultrasonic techniques for investigation of large and complex geometry objects, such as composites for aerospace applications and petroleum tanks, have been developed. The investigation of propagation effects of ultrasonic guided (Lamb) waves in the plates of the tank floor has indicated relation between reconstructed properties of guided waves and expected presence of corrosion deposits.

Computational Simulation and Optimization of Functionally Graded Auxetic Structures Made From Inverted Tetrapods

Auxetic cellular materials show great potential for improved properties in case of impact loading. Due to this potential, auxetic structures made from inverted tetrapods are extensively analyzed experimentally and computationally. The built samples are compressed in two orthogonal directions to determine their base mechanical properties and deformation mechanisms. The lattice computational model is developed and validated using the experimental results. A new shape optimization procedure to develop new auxetic structures with functionally graded geometry is proposed and tested in a case study. With introduction of the functionally graded geometry the response of the auxetic structure can be tailored to a particular loading condition, which is especially important in impact or ballistic performance of modern composite materials.

Effect of Composition of Fibers on Properties of Hybrid Composites

Fibers embedded in the matrix of another material are the best example of modern day composite materials. Hybrid Composites made out of an amalgamation of Natural Fibers such as banana, jute, and coir along with glass fiber embedded in polymers have potential applications in automotive, aircraft and marine industries for their unique characteristics like high specific strength, light weight, design flexibility, corrosion resistance, biodegradability and low cost. In this work, epoxy hybrid composites reinforced with glass fiber mats and banana, jute, coir fibers of random lengths between 10-25 mm are prepared by varying their compositions in terms of weight percentage. The composites are fabricated by hand lay-up process and cut into test specimens as per ASTM Standards. Their mechanical characteristics such as Tensile Strength, Flexural Strength, Impact Strength, Hardness, Density and Water Absorption Capacity are evaluated and analysed.

TRIBOLOGICAL TESTS OF THE NANOMATERIALS USED TO RECONSTRUCT MOLARS AND PREMOLARS WITH THE APPLICATION OF THE DIRECT METHOD

Physiological abrasion of teeth is a process of gradual loss of the hard tissue of opposite teeth resulting from age-related natural dental wear. In abrasion, the cusps and their slopes in the jaw and the mandible become flattened due to the mechanical load applied. The aim of this paper is to carry out a tribological and microstructural evaluation of modern composite materials used to reconstruct the teeth in the lateral part of the dental arch. Five light-cured composite materials were selected for tests. The tests involved the coefficient of friction and resistance to wear in a sliding contact in the presence of artificial saliva and the microstructure of the external surface of samples before the wear process and in the wear-related damaged area. The test method applied, which combines a biomechanical analysis of resistance to wear and the analysis of the microstructure before the wear process and in the wear-related damaged area, makes it possible to evaluate the tribological properties of composite materials used to reconstruct teeth in the lateral part of the dental arch.

Minimally invasive restorative treatment with direct composite veneers – case report

Summary Esthetic and minimally invasive restorative techniques are current topics in dentistry. Introduction of modern composite materials and adhesive technology provided numerous options for design of esthetic restorations without invasive teeth preparation common for traditional prostodontic restorations. Modern esthetic dentistry can provide solutions for simple as well as complex cases by implementation of various alternatives.

Thermal state of the shell for supersonic part of the ramjet nozzle

A mathematical model describing the temperature distribution in a non-cooled nozzle shell was constructed. Analysis of this model showed that the extreme temperatures are permissible for some modern and promising heat-resistant composite materials.

Развитие научной реставрации и консервации памятников архитектуры в России

The principle of science in the scientific restoration is the availability and provision of specialists with reliable information and modern advances in construction. The relevant tasks are to implement new developments on restoration of bearing capacity of structures and the use of modern composite materials. Innovative developments in the field of restoration are a specific form of management of development of construction processes and technologies allowing to change the structure, organization and content of the reconstruction process as a whole. The subject of research are the new technological developments in the field of chemical and construction industry. The use of such developments allows us to solve the difficult tasks to prevent the destruction, and to give the historical uniqueness to the architectural monuments of world importance.

Effects of two-body wear on microfill, nanofill, and nanohybrid restorative composites

Background: The purpose of this study was to investigate two-body wear resistance and hardness of different three modern composite materials. Methods: In the conditions recommended by the manufacturer five pieces were produced from each material. All samples were kept in distill water for 1 week and determined Vickers hardness (HV) before two-body wear test. Then, two-body wear tests were performed using a computer controlled chewing simulator. In this study, the chewing simulator was programmed to provide a 2 mm vertical movement and a 0.7 mm horizontal movement. For each wear test, Al2O3 with a diameter of 6 mm was used as antagonist material. The mean volume loss of all samples after the wear tests was determined with three dimensional profilometry. In addition to a random specimen was selected from each test group and SEM images were taken for analysis of wear tracks. Mean and standard deviation values were calculated and evaluated with the one-way ANOVA. Results: The hardness values of the materials tested in this study were measured between about 49 HV and 78 HV. Significantly, lowest mean volume loss was detected for the Heliomolar at about 3.1 μm3 whereas the highest mean volume loss was detected for the Silorane at about 6.4 μm3 after 360.000 chewing cycles. Conclusions: However, among the materials tested in this study suggested correlations between HV and two-body wear resistance are not significant.

The Effect of Filler Content on the Mechanical Properties of Polymer Composite

A composite material is a macroscopic combination of two or more distinct materials, having a recognizable interface between them. Modern composite materials are usually optimized to achieve a particular balance of properties for a given range of applications. Composites are commonly classified at two distinct levels. The first level of classification is usually made with respect to the matrix constituent. The major composite classes include organic – matrix composites (OMC's), metal – matrix composites (MMC's), and ceramic – matrix composites (CMC's). The OMC's is generally assumed to include two classes of composites: polymer – matrix composites (PMC's) and carbon – matrix composites [1]. The composite material used in the work belongs to the PMC's and the composite is formed by the polymer matrix - high density polyethylene. As filler was used hard-magnetic strontium ferrite. Composite samples were prepared with different filler content (0%, 60%, 70%, 80%). Testing of polymer composites included: tensile test, elongation at break, impact test, hardness test.

Influence of water and oil immersion on the tribological properties of Excentrodendron hsienmu

Modern composite materials and lignum vitae are widely studied and used in water-lubricated bearings. Noise, wear and tear, environmental pollution, and limited resources restrict the application of these materials. Thus, alternatives to lignum vitae for water-lubricated bearings should be identified and developed. In this work, the chemical composition and mechanical and tribological properties of water-, vegetable oil-, and gear oil-immersed and wax- and water-extracted Excentrodendron hsienmu (E. hsienmu) samples were studied. Results showed that the friction coefficients of the water- and gear oil-immersed and waxand water-extracted E. hsienmu samples are significantly smaller than those of the wax- and water-extracted lignum vitae samples. The grinding crack widths of the water-extracted gear oil-immersed E. hsienmu samples are smaller than those of the water-immersed lignum vitae samples. The preliminary results show that it is possible to provide an environmentally friendly method that could replace lignum vitae and other composite materials for water-lubricated bearings.

Composite materials molding simulation for purpose of automotive industry

Composite materials loom large increasingly important role in the overall industry. Composite material have a special role in the ever-evolving automotive industry. Every year the composite materials are used in a growing number of elements included in the cars construction. Development requires the search for ever new applications of composite materials in areas where previously were used only metal materials. Requirements for modern solutions, such as reducing the weight of vehicles, the required strength and vibration damping characteristics go hand in hand with the properties of modern composite materials. The designers faced the challenge of the use of modern composite materials in the construction of bodies of power steering systems in vehicles. The initial choice of method for producing composite bodies was the method of molding injection of composite material. Molding injection of polymeric materials is a widely known and used for many years, but the molding injection of composite materials is a relatively new issue, innovative, it is not very common and is characterized by different conditions, parameters and properties in relation to the classical method. Therefore, for the purpose of selecting the appropriate composite material for injection for the body of power steering system computer analysis using Siemens NX 10.0 environment, including Moldex 3d and EasyFill Advanced tool to simulate the injection of materials from the group of possible solutions were carried out. Analyses were carried out on a model of a modernized wheel case of power steering system. During analysis, input parameters, such as temperature, pressure injectors, temperature charts have been analysed. An important part of the analysis was to analyse the propagation of material inside the mold during injection, so that allowed to determine the shape formability and the existence of possible imperfections of shapes and locations air traps. A very important parameter received from computer analysis was to determine the occurrence of the shrinkage of the material, which significantly affects the behaviour of the assumed geometry of the tested component. It also allowed the prediction of existence of shrincage of material during the process of modelling the shape of body. The next step was to analyse the numerical analysis results received from Siemens NX 10 and Moldex 3D EasyFlow Advanced environment. The process of injection were subjected to shape of prototype body of power steering. The material used in process of injection was similar to one of excepted material to be used in process of molding. Nextly, the results were analysed in purpose of geometry, where samples has aberrations in comparison to a given shape of mold. The samples were also analysed in terms of shrinkage. Research and results were described in detail in this paper.

Damage of Bi-material Structures and Reinforced Composites with Different Industrial Applications

The present paper consists of two parts. In the first part the interface delamination of bimaterial structures (unit cell of wind rotor blade) with different material properties under mechanical loading at physical conditions – electricity, temperature and moisture is under consideration. The investigation of the above mentioned structures are motivated by the importance for safety of devices used for energy industry applications. The second part is devoted to renovation of old buildings by using new and modern composite materials. The goal is to find via mathematical modelling the safety zone, the reliability of the structures considered and the detection of possible interface delamination as a function of geometrical, material and physical parameters as well as the pull-out force of modern composites used in building industry. The analysis provided in both parts is based on the modified shear lag method. The results obtained in the first and second parts of the paper are illustrated by tables and figures. Some recommendations and possible criterions are proposed, as well.

Modern composite materials for switching and welding equipment. Information 2. Application of high-rate vacuum evaporation methods for manufacturing electric contacts and electrodes

Modern composite materials for switching and welding equipment. Information 2. Application of high-rate vacuum evaporation methods for manufacturing electric contacts and electrodes