scholarly journals Effect of Shape of Armoring Fibers on Strength of Composite Materials

2021 ◽  
Vol 12 (2) ◽  
pp. 2703-2708
Author(s):  
Y.A.Vahterova, Et. al.
Keyword(s):  
Composite Materials ◽  
Deformation Rate ◽  
Experimental Studies ◽  
Layered Material ◽  
Carbon Plastic ◽  
Test Results ◽  
Static Characteristics ◽  
Calculation Results ◽  
Margin Of Safety ◽  
Design Calculations

In this work, experimental studies of the effect of fiber curvature on the strength and ultimate deformations of epoxy carbon plastic samples under loading are carried out. On the basis of the experimental studies carried out, the static characteristics of the composite layered material, which are promising for use in the structures under consideration, have been determined. Based on the test results, it was demonstrated that in the design calculations for the products under consideration, it is possible to use static characteristics, since an increase in the deformation rate of the material leads to an increase in strength and, therefore, the calculation results will provide an additional margin of safety.

Numerical and experimental studies on the thermal and static characteristics of multi-leaf foil thrust bearing

2021 ◽  
pp. 135065012110110
Author(s):  
Yu Guo ◽  
Yu Hou ◽  
Qi Zhao ◽  
Xionghao Ren ◽  
Shuangtao Chen ◽  
...  
Keyword(s):  
High Speed ◽  
Thrust Bearing ◽  
Load Capacity ◽  
Failure Process ◽  
Experimental Studies ◽  
Elastic Model ◽  
Static Characteristics ◽  
Bearing Load ◽  
Foil Thrust Bearing ◽  
Cooling Air

Foil bearing is considered to be a promising supporting technology in high-speed centrifugal machinery. Due to the high-speed shearing effect in the viscous lubricant film, heat generation could not be ignored. In this paper, a thermo-elastic model of the multi-leaf foil thrust bearing is proposed to predict its thermal and static characteristics. In the model, modified Reynolds equation, energy equation, and Kirchhoff equation are solved in a coupling way. The contact area between the foil and welding plate is taken into account. Besides, the effect of cooling air on the bearing temperature is investigated. The ultimate load capacity and transient overload failure process of the bearing is analyzed and discussed. The effect of rotation speed on the bearing temperature is more obvious than that of the bearing load. The bearing temperature drops obviously by introducing the cooling air, and the cooling effect is improved with the supply pressure. The transient overload failure of the bearing occurs when the bearing load exceeds the ultimate value.

Effect of Wood Filler Concentration on Physical and Mechanical Properties of PLA-Based Composites

2021 ◽  
Vol 887 ◽  
pp. 110-115
Author(s):  
G.A. Sabirova ◽  
R.R. Safin ◽  
N.R. Galyavetdinov
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Composite Materials ◽  
Impact Strength ◽  
Wood Flour ◽  
Experimental Studies ◽  
Physical And Mechanical Properties ◽  
Filler Concentration ◽  
High Concentration

This paper presents the findings of experimental studies of the physical and mechanical properties of wood-filled composites based on polylactide (PLA) and vegetable filler in the form of wood flour (WF) thermally modified at 200-240 °C. It also reveals the dependence of the tensile strength, impact strength, bending elastic modulus, and density of composites on the amount of wood filler and the temperature of its thermal pre-modification. We established that an increase in the concentration of the introduced filler and the degree of its heat treatment results in a decrease of the tensile strength, impact strength and density of composite materials, while with a lower binder content, thermal modification at 200 °C has a positive effect on bending elastic modulus. We also found that 40 % content of a wood filler heated to 200 °C is sufficient to maintain relatively high physical and mechanical properties of composite materials. With a higher content of a wood filler, the cost can be reduced but the quality of products made of this material may significantly deteriorate. However, depending on the application and the life cycle of this product, it is possible to develop a formulation that includes a high concentration of filler.

scholarly journals FEA and Experimental Studies of Adaptive Composite Materials with SMA Wires

2008 ◽  
Author(s):  
K. Kanas ◽  
C. Lekakou ◽  
N. Vrellos ◽  
Alexander M. Korsunsky
Keyword(s):  
Composite Materials ◽  
Experimental Studies ◽  
Adaptive Composite

scholarly journals Determination of Nearest Emergency Service Office using Haversine Formula Based on Android Platform

2018 ◽  
Vol 5 (2) ◽  
pp. 270-278 ◽  
Author(s):  
M. Basyir ◽  
M. Nasir ◽  
Suryati Suryati ◽  
Widdha Mellyssa
Keyword(s):  
Emergency Service ◽  
Emergency Services ◽  
Message Delivery ◽  
Test Results ◽  
Average Delay ◽  
Accuracy Test ◽  
Calculation Results ◽  
Testing Accuracy ◽  
Selection Of

Emergency Reporting Application is an android-based application that serves to help the community in reporting the emergency condition. This application allows users to choose and contact the emergency services office, without the need to notice their position and phone number. Selection of emergency services office is also automatically selected by the system by taking into account the distance between the complainant and the emergency services office. The selected emergency services office is the nearest emergency service office from the complainant so that the delay in coming assistance can be minimized. Therefore, this proposed application requires a GPS feature to recording, reporting and SMS positioning for message delivery of reports. The distance between the position of the complainant and the position of the emergency service office, in the form of latitude and longitude data, is requested using the Haversine formula taking into account the degree of curvature of the earth. Emergency service offices include police and hospital offices spread over 25 different districts. Furthermore, the reporter's position calculation results were compared with all selected emergency service offices and obtained 1 nearest emergency service office. Calculating the accuracy and delay value of the system will do system testing. Accuracy test results using the method of 100% Haversine and the average delay of the system is 4.5 seconds.

scholarly journals Research of transient processes in case of single-phase insulation faults in low-voltage ship power grids, taking into account the resistance at the fault point

2020 ◽  
pp. 49-54
Author(s):  
И.Е. Кажекин
Keyword(s):  
Single Phase ◽  
Low Voltage ◽  
Experimental Studies ◽  
Power Grids ◽  
Transient Processes ◽  
Safety Issues ◽  
Physical Experiments ◽  
Marine Industry ◽  
Calculation Results ◽  
Constant Potential

В работе рассмотрены вопросы безопасности бортовых электросетей объектов морской индустрии, показано влияние перенапряжений на их основные показатели, которыми определяются опасности смертельных электротравм, опасности возникновения пожаров и взрывов. Представлены результаты математического моделирования электрического разряда по уравнению Майра с учетом особенностей переходного процесса при однофазных замыканиях на корпус. Показана роль напряжения смещения нейтрали по постоянному потенциалу, наибольшие значения которого формируются при неустойчивом контакте фазы с корпусом судна. Описаны результаты экспериментальных исследований переходных процессов, сопровождающихся возникновением неустойчивыми искровыми разрядами. Сравнение результатов расчета по предложенной методике с результатами физических экспериментов показало весьма удовлетворительную сходимость. Предложенная модель может быть использована для уточнения показателей, характеризующих безопасность судовых электросетей. The paper deals with the safety issues of on-board power grids of the marine industry facilities, shows the influence of overvoltages on their main indicators, which determine the dangers of fatal electrical injuries, the risk of fires and explosions. The results of mathematical modeling of an electric discharge according to the Mayr equation, taking into account the features of the transient process in single-phase short circuits to the case, are presented. The role of the bias voltage of the neutral at a constant potential is shown, the highest values ​​of which are formed during unstable contact of the phase with the ship's hull. The results of experimental studies of transient processes accompanied by the appearance of unstable spark discharges are described. Comparison of the calculation results by the proposed method with the results of physical experiments showed a very satisfactory convergence. The proposed model can be used to refine the indicators characterizing the safety of ship power grids.

scholarly journals Physico-technical approach to design of composites from mineral and polymer technogenic resources

2015 ◽  
Vol 1 ◽  
pp. 162 ◽  
Author(s):  
Gotfrīds Noviks
Keyword(s):  
Composite Materials ◽  
Experimental Studies ◽  
Process Efficiency ◽  
Operating Characteristics ◽  
Forming Process ◽  
Polymer Waste ◽  
Composite Forming ◽  
Different Types ◽  
Low Levels

<p class="R-AbstractKeywords"><span lang="EN-US">Artificial composite materials are currently being produced in large quantities, they are diverse and they are widely used in the economy. There have been extensive theoretical and experimental studies of different types of components, developed the calculation methods of composites production with predefined properties.</span></p><p class="R-AbstractKeywords"><span lang="EN-US">At the same time industry produces a lot of mineral and polymer waste, which are practically technogenic resources, but their use is currently at quite low levels. The paper examines the possibilities to use technogenic resources- mineral (such as ash and clay) and organic (polymers -PET containers) for producing qualitative composite materials. For this purpose theoretical analysis and calculations of the physical properties of components and process parameters that determine the operating characteristics of the composite material were carried out.</span></p><p class="R-AbstractKeywords"><span lang="EN-US">Composite-forming process efficiency determinative parameters were analysed: adhesion, the specific surface energy, specific free surface, adsorption capacity and the degree of dispersion of the particles.</span></p><p class="R-AbstractKeywords"><span lang="EN-US">The role of external factors in processing of composite were examined – temperature, concentration of components.</span></p><p class="R-AbstractKeywords"><span lang="EN-US">The characteristics of prepared samples of composites showed the possibility to use these waste for the development of qualitative products for different purposes.</span></p>

scholarly journals HUBUNGAN PIJAT BAYI DENGAN PERKEMBANGAN MOTORIK BAYI USIA 1 – 12 BULAN DI DESA PUNDUNGSARI BULU SUKOHARJO

2015 ◽  
Vol 3 (1) ◽  
Author(s):  
Rahayu Setyaningsih ◽  
Kristiani Eka Prasetyo Wat ◽  
Asri Utami
Keyword(s):  
Rapid Growth ◽  
Experimental Studies ◽  
Sampling Technique ◽  
Test Results ◽  
Infant Massage ◽  
Chi Square ◽  
The Public ◽  
Touch Therapy ◽  
Mother And Child ◽  
Long Time

AbstractIntroduction: Infant massage is a touch therapy oldest known to the public. Infant massage is one of the communication between mother and child is communication through touch. Infant massage has been known to man for a long time and reduced down - generations. Age 1-12 months is a period of rapid growth that is traversed by the child, including motoric development. Infant massage can provide a stimulus to promote weight and to increase motoric development.The purpose: Of this study was to correlate of infant massage and motoric development in infants aged 1-12 months in District Pundungsari Bulu Sukoharjo.The subjects: Were mother with infants aged 1-12 months, in the District Pundungsari. Sampling is done with total sampling technique. They are 33 sample in this research.Methods: This study was a non-experimental studies, correlation approach. Data obtained by the method of questionare, which is mother has filled the questionare about baby massage in infants aged 1-12 months and motoric development. The data have been collected and analyzed by chi square with p= 0.05. The research found that respondents do baby massage with continue and not continue and motoric development found delayed, normal and advance. After the test results obtained chi square p 0.000 to p <0.05, which means Ha accepted and Ho rejected.The conclusion: Of this study is infant massage correlate with motoric development in infants aged 1-12 months in District Pundungsari Bulu Sukoharjo.Keywords: Infant massage, motoric development

scholarly journals The deformability of compressed concrete elements strengthened with FRCM composite materials

2013 ◽  
Vol 12 (1) ◽  
pp. 163-170
Author(s):  
Tomasz Trapko
Keyword(s):  
Composite Materials ◽  
Experimental Studies ◽  
Influence Of Temperature ◽  
Cementitious Matrix ◽  
Concrete Elements

In the paper the results of experimental studies performed on compressed concrete elements strengthened with composite fabric of FRCM (Fibre Reinforced Cementitious Matrix) technology are presented. In the studies the influence of temperature, the number of composite fabric layers and the length of ending overlap on the value and distribution of circumferential limit strains was analyzed.

scholarly journals DYNAMICS OF LAYER-BY-LAYER DESTRUCTION OF CARBON PLASTIC BY LIGHTNING CURRENTS: THEORY AND EXPERIMENT

2020 ◽  
pp. 67-73
Author(s):  
Igor A. Guschin
Keyword(s):  
Experimental Studies ◽  
Neumann Boundary ◽  
Aircraft Design ◽  
Carbon Plastic ◽  
Layer By Layer ◽  
Experiment Data ◽  
Conductive Medium ◽  
Transverse Current ◽  
Number Of Layers ◽  
Current Densities

On the basis of two models of lightning currents spreading on carbon plastic, the criteria of material destruction are determined. One of the models – the anisotropic conductive medium model from the Laplace equation with specified Neumann boundary conditions – makes it possible to obtain an exact solution in the form of Bessel functions for longitudinal and transverse current densities and to consider the material destruction zones by the radius and the depth. The model adequately describes the experiment with different arrangement of electrodes simulating the passage of lightning currents on constructions made of conductive composite and metal. The second – the model of composite layered structure – is constructed using the diagram of carbon plastic substitution and makes it possible to find the distribution of currents by a numerical method. The results of the calculations for both models are well consistent. The dynamics analysis of carbon plastic destruction revealed the criteria of destruction with parameters of real carbon plastic and experiment data that do not contradict the parameters of carbon plastic destruction obtained in foreign experimental studies. These criteria allow to determine the dependence between the value of the current integral and the number of layers of the composite material. Options with a small number of layers and with a large one when the reach-through breakdown criterion is possible were taken into account. Comparison of calculated and experimental destruction data showed good curve matching. The obtained criteria make it possible to predict the effects of lightning exposure under different material parameters and to take measures to improve the lightning resistance of carbon plastic products at the stage of aircraft design.

scholarly journals A study into the scale effect on the strength properties of polymer composite materials

2019 ◽  
Vol 5 (2) ◽  
pp. 103-108
Author(s):  
Valentina V. Kiryushina ◽  
Yuliya Yu. Kovaleva ◽  
Petr A. Stepanov ◽  
Pavel V. Kovalenko
Keyword(s):  
Composite Materials ◽  
Polymer Composite ◽  
Scale Effect ◽  
Mechanical Characteristics ◽  
Full Scale ◽  
Sample Thickness ◽  
Polymer Composite Materials ◽  
Test Machine ◽  
Test Results ◽  
Laboratory Sample

Polymer composite materials (PCM) are used extensively and are viewed as candidates for application in various industries, including nuclear power. Despite a variety of methods and procedures employed to investigate the mechanical characteristics of PCMs, the use of the laboratory sample mechanical test results to design and model large-sized structures is not always fully correct and reasonable. In particular, one of the problems is concerned with taking into account the scale parameter effects on the PCM strength and elastic characteristics immediately in the product. The purpose of the study is to investigate the scale effects on the mechanical characteristics of glass reinforced plastics using phenolformaldehyde and silicon-organic binders and a fabric quartz filler. Samples of four different standard sizes under GOST 25604-82 and GOST 4648-2014 were tested for three-point bending using an LFM-100 test machine to estimate the scale effect. The thicknesses of the model samples were chosen with regard for the wall thicknesses of full-scale products under development or manufactured commercially and the test machine features, and varied in the limits of 1.6 to 7.5 mm. The tests showed that strength decreased as the sample thickness was increased to 3 mm and more both at room and elevated (200 to 500 °C) temperatures, which can be described by an exponential function based on the Weibull statistical model. The values of the Weibull modulus that characterizes the extent of the scale effect on the strength of the tested materials were 4.6 to 6.7. The average bend strength in the sample thickness range of 3 mm and less does not vary notably or tends to increase slightly as the thickness is increased. This fact makes it possible to conclude that estimation of allowable stresses in a thin-wall product requires the use of test results for samples with a thickness that is equal to the product wall thickness since standard samples may yield overestimated allowable stress values and lead, accordingly, to incorrect calculations of the strength factor. The results obtained shall be taken into account when defining the allowable levels of operation for full-scale products and structures of polymer composites based on the laboratory sample strength data as well as when estimating their robustness as a characteristic of the product’s fail-safe operation.

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