IMPACT OF HIGH VOLTAGE ELECTRIC DISCHARGES ON THE CURED POLYMER COMPOSITE MATERIALS, MODIFIED IN A MICROWAVE ELECTROMAGNETIC FIELD

2020 ◽  
pp. 6-12
Author(s):  
I. V. Zlobina ◽  
A. A. Korotich
Keyword(s):  
Electromagnetic Field ◽  
Surface Layer ◽  
Composite Materials ◽  
Carbon Fiber ◽  
Minimum Wage ◽  
Polymer Composite ◽  
High Voltage ◽  
Polymer Composite Materials ◽  
Structural Elements ◽  
The Impact

Due to the widespread use of carbon fiber-reinforced polymer composite materials (PCM) in the structural elements of aircraft with a distributed surface layer of lightning-proof coating (MFP) in the form of metal grids to reduce the risk of lightning strikes and the possibility of increasing their strength characteristics by processing in the microwave electromagnetic field, the need to study the impact of this method of processing on the resistance of PCM to high voltage electrical discharges. The studies of the impact of the discharge voltage 180…200 kV on samples of PCM with the minimum wage and no minimum wage. It is established that pretreatment of samples of the cured polymer composite MW in a microwave electromagnetic field energy flux density (17…18)104 µw/cm2 does not degrade their molniezaschita characteristics and contributes to reducing the size of the damaged area up to 1.5 times. Samples processed in the microwave electromagnetic field without MSP do not have delaminations and burns in contrast to the control ones. The obtained results indicate the possibility of strengthening treatment in the microwave electromagnetic field of structural elements of carbon fiber distributed in the surface layer of the MSP in the form of a metal grid.

STRUCTURING OF CURED POLYMERIC COMPOSITE MATERIALS IN A MICROWAVE ELECTROMAGNETIC FIELD

2021 ◽  
pp. 3-9
Author(s):  
I. V. Zlobina
Keyword(s):  
Electromagnetic Field ◽  
Composite Materials ◽  
Polymer Composite ◽  
Contact Interaction ◽  
Energy Systems ◽  
Polymeric Composite ◽  
Strength Characteristics ◽  
Polymer Composite Materials ◽  
Reinforcing Fibers ◽  
The Matrix

Based on studies of the microstructure of the matrix of cured polymer composite materials and the area of its contact interaction with reinforcing fibers, the hypothesis of its structuring in the microwave electromagnetic field with an increase in the contact interaction surfaces due to an increase in the number of agglomerates with small transverse dimensions and a decrease in porosity in the macro- and mesopore regions is substantiated. These effects can be used as a basis for increasing the strength characteristics and uniformity of their values after exposure to a microwave electromagnetic field. The results of this work can be used in the development of technologies for finishing hardening of products made of carbon and fiberglass for various transport and energy systems.

scholarly journals A method of manufactoring pipes from polymer composite materials for aircraft structures

2020 ◽  
Vol 26 (5) ◽  
pp. 228-27
Author(s):  
S.O. Odaisky ◽  
◽  
O.M. Potapov ◽  
S.V. Fedorenko ◽  
A.P. Shchudro ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Composite Materials ◽  
Carbon Fiber ◽  
Polymer Composite ◽  
Modulus Of Elasticity ◽  
Coefficient Of Thermal Expansion ◽  
Longitudinal Direction ◽  
Polymer Composite Materials ◽  
Thermophysical Characteristics ◽  
Reinforcement Scheme

The frame power structures are widely applied when designing aircraft, in which composite rod elements are used to reduce the mass and size characteristics. To solve the problem of manufacturing rod elements from polymer composite materials, we developed a technology for the manufacture of carbon fiber pipes using an existing machine for winding carbon fiber, which provides the necessary strength and rigidity mainly in the longitudinal direction.When calculating the rod elements, all the loads that will affect the structure as well as the coefficient of thermal expansion should be taken into account. To achieve the required physical, mechanical, and thermophysical characteristics, the optimal scheme of reinforcement is the scheme with a quasi-longitudinal direction of the fibers. We developed the method of manufacturing based on the technology allowing us to obtain a reinforcement scheme with fiber orientation in the quasi-longitudinal direction with a reinforcement angle of about 1° by a combined method of layer-by-layer winding of carbon fiber. As a result of technological testing, we obtained samples of carbon fiber rod elements, which were used to confirm the calculated characteristics. To confirm the physico-mechanical and thermophysical characteristics, we determined the assessment of limit of strength and modulus of elasticity in bending, the limit of strength and modulus of elasticity in torsion, the limit of strength and modulus of elasticity in compression, and the coefficient of thermal expansion. The obtained characteristics of the dependences of the elasticity modulus of the pipe prototype material at the fibers’ orientation angle correlate with theoretical calculations. The presented method has the patent UA 128613 U.

scholarly journals Classification of energy impacts by their effect on the structure and properties of reinforced reactoplasts

2021 ◽  
Vol 83 (2) ◽  
pp. 197-201
Author(s):  
I. V. Cheremukhina
Keyword(s):  
Composite Materials ◽  
Impact Strength ◽  
Polymer Composite ◽  
Polymer Composite Material ◽  
Polymer Chains ◽  
Polymer Composite Materials ◽  
Mesh Structure ◽  
Wave Nature ◽  
The Impact

The use of various physical influences is an economical and highly effective direction for regulating and improving the characteristics of the modified reinforced polymer composite materials developed in this work. The methods of energy effects studied in this work were used at the stage of impregnation of technical threads of various chemical nature with an oligomeric binder and a hardener (when preparing prepregs by the traditional method) or with a binder solution and a curing system (when preparing prepregs by the method of layered application of components) Based on the conducted research, a classification of the applied methods of physical modification according to the principle of the influence of energy fields is proposed. The studied methods of energy effects are divided into orienting and energetically energizing effects. The first group includes treatments with constant magnetic (PMP) or electric fields (PEP), and constant mechanical loads. The second group includes energy effects that have a wave nature (energetically energizing), and vibration, ultrasonic effects, and ultraviolet radiation are attributed to them. Modification methods of the first group contribute to a decrease in the mobility of binder molecules during curing, while the formation of branches of polymer chains occurs during the curing process, which leads to a predominant increase in the destructive stress during static bending. Energetically energizing effects contribute to the relative acceleration of the process of linear growth of polymer chains during curing, which is accompanied by the formation of a more sparsely cross-linked mesh structure, which leads to a predominant increase in impact strength. Of the two competing processes in the curing of epoxy oligomers, this one requires a higher activation energy, which is confirmed by the results of studies. Analyzing the results obtained, it can be concluded that the modification methods used in the work allow not only to obtain polymer composite materials with high strength characteristics, but also to directly adjust the properties of composites depending on the requirements for the products. Orienting modification methods lead to hardening of the resulting polymer composite material with a predominant increase in the destructive stress during static bending from 20 to 47%. When using energetically energizing influences in the technology of producing reinforced reactoplasts, the impact strength increases mainly from 19 to 40%.

THE EFFECT OF MICROWAVE ELECTROMAGNETIC FIELD ON THE HARDNESS OF CARBON FIBER-REINFORCED PLASTIC WITH LIGHTNING PROTECTION GRID DISTRIBUTED IN THE SURFACE LAYER

2020 ◽  
Vol 0 (4) ◽  
pp. 5-11
Author(s):  
I.V. ZLOBINA ◽  
Keyword(s):  
Electromagnetic Field ◽  
Surface Layer ◽  
Carbon Fiber ◽  
Surface Hardness ◽  
Lightning Protection ◽  
Fiber Reinforced ◽  
Short Term Exposure ◽  
Structural Density ◽  
Carbon Fiber Reinforced ◽  
The Impact

Based on the analysis of scientific and technical literature and trends in the development of multi-purpose aircrafts, we can see a steady extension of the use of polymer composite materials (PCM) in their design. The importance of lightning protection is noted for aircrafts, the skin of which consists mainly of the PCM, and it is shown that one of the common means is a lightning protection coating (LPC) in the form of a metal grid distributed in the PCM surface layer. Anisotropy of PCM properties and reduced fracture toughness in comparison with metals necessitates the improvement of PCM compositions and technologies of their formation as well as the development of methods for final hardening treatment in the cured state, which can be effectively performed under the effect of microwave electromagnetic field. Consideration is given to the influence of a short-term exposure to microwave electromagnetic field on the stability of carbon fiber-reinforced PCM with PLC against impact loads, as well as on the surface hardness. Our findings show a decrease in the damaged area of the impact zone by 40-60% and the absence of microcracking and delamination as well as an increase in hardness by 7.8%. Particular emphasis is placed on a 3-fold decrease in the spread of hardness values after the microwave exposure, this indicating a significant increase in the uniformity of this important characteristic for the component performance. As a mechanism of these modifications, it is proposed to reduce the pore size and porosity and to increase the number of points of contact interaction between matrix and fiber agglomerates that ensure an increase in the structural density.

Method of parametric optimization in the problems of passenger airliner design

2020 ◽  
Author(s):  
A.A. Bolshikh ◽  
V.P. Eremin
Keyword(s):  
Composite Materials ◽  
Polymer Composite ◽  
Parametric Optimization ◽  
Polymer Composite Materials ◽  
Preliminary Design ◽  
Structural Elements ◽  
The Finite Element Method ◽  
Current Trends ◽  
Box Structure ◽  
Mass Perfection

The paper describes current trends in the design of load-bearing structural elements of modern airliners made using polymer composite materials. In modern passenger airliners, polymer composite materials are used to ensure mass perfection of both lightly loaded elements and critical units, including wing and fin boxes. By means of the finite element method, a box model was created using shell finite elements. Parametric optimization was carried out with account for the anisotropic properties of structural materials. The purpose of the work is to develop a methodology for calculating the structural strength elements of the box and justify the required thicknesses with restrictions on compressive / tensile deformations and loss of stability. The developed methodology makes it possible to obtain a box structure with a minimum mass, while maintaining the necessary stiffness and strength characteristics at the stage of preliminary design.

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