scholarly journals THE TREATMENT EFFECT IN A MICROWAVE ELECTROMAGNETIC FIELD TO CHANGE THE FLEXURAL STRENGTH OF STRUCTURAL ELEMENTS OF THE CURED CARBON-FIBER COMPOSITES UNDER THE INFLUENCE OF ENVIRONMENTAL FACTORS

2020 ◽  
pp. 20-22
Author(s):  
I. Zlobina ◽  
N. Bekrenev ◽  
I. Katsuba
Keyword(s):  
Electromagnetic Field ◽  
Carbon Fiber ◽  
Environmental Factors ◽  
Bending Strength ◽  
Climatic Factors ◽  
Fiber Composites ◽  
Carbon Fiber Composites ◽  
Structural Elements ◽  
Comparative Tests ◽  
Three Point Bending

The article describes the results of comparative tests for three-point bending of carbon fiber samples processed in a microwave electromagnetic field after being exposed to environmental factors for 3 months. It is shown that the influence of external climatic factors leads to a decrease in the bending strength of control and experimental samples by 3.7% and 1.4%, respectively. At the same time, the strength of the test samples increases by 8% in comparison with the control ones.

CORRELATION DEPENDENCES OF THE BENDING STRENGTH OF POLYMER COMPOSITE MATERIALS MODIFIED IN A MICROWAVE ELECTROMAGNETIC FIELD ON THE MOISTURE CONTENT DURING EXPOSURE IN FULL-SCALE CONDITIONS

2021 ◽  
pp. 3-9
Author(s):  
I. V. Zlobina ◽  
I. S. Katsuba
Keyword(s):  
Electromagnetic Field ◽  
Composite Materials ◽  
Carbon Fiber ◽  
Moisture Content ◽  
Bending Strength ◽  
Climatic Factors ◽  
Experimental Studies ◽  
Three Point Bending ◽  
Treated Carbon ◽  
Control Samples

Experimental studies of the influence of external climatic factors, taking into account exposure, on the change in the bending strength of control and microwave – treated carbon and fiberglass samples in the cured state were performed. An increase in the limit stresses of three – point bending of experimental carbon fiber samples compared to the control ones was found by 7…12 %, and fiberglassby 4…7 %. It is shown that with an increase in exposure to 14 months, the strength of control samples of carbon and fiberglass decreases by an average of 10 %. At the same time, the strength of the prototypes is reduced only by 4.4 %. With an increase in the moisture content of both control and experimental samples, a decrease in their strength is observed. In this case, the linear correlation is average (from– 0.44 to – 0.615). It is established that for experimental samples, the influence of the amount of absorbed moisture on the strength is manifested to a much lesser extent. For carbon fiber, the reduction is 16.6 %, for fiberglass – 12 %.

scholarly journals REDUCING THE INFLUENCE OF ENVIRONMENTAL FACTORS ON THE BENDING DEFORMATION OF CURED CARBON FIBER BY MICROWAVE PROCESSING

2021 ◽  
pp. 56-58
Author(s):  
I. V. Zlobina
Keyword(s):  
Electromagnetic Field ◽  
Composite Materials ◽  
Carbon Fiber ◽  
Environmental Factors ◽  
Flux Density ◽  
Environmental Conditions ◽  
Climatic Factors ◽  
Transverse Load ◽  
Bending Deformation ◽  
Energy Flux Density

The article discusses the results of a study of bending deformation and creep under transverse load of cured polymer composite materials (PCM), which were located for 8 months in full-scale environmental conditions in Saratov. It was found that being under the influence of natural climatic factors for the specified time leads to an increase in the bending deformation of samples from 13,5 to 25,4%, depending on the load. Processing in a microwave electromagnetic field with a frequency of 2450 MHz with an energy flux density of (17-18) x10 mW / cm for 2 minutes reduces bending deformation by (9-18)%, and creep - up to 4 times.

THE INFLUENCE OF CLIMATIC FACTORS ON RESIDUAL STRESSES IN NANOMODIFIED CYANATE ESTER-BASED CFRP

2021 ◽  
pp. 104-112
Author(s):  
V.O. Startsev ◽  
◽  
E.V. Nikolaev ◽  
A.M. Vardanyan ◽  
A.A. Nechaev ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Residual Stresses ◽  
Bending Strength ◽  
Climatic Factors ◽  
Linear Thermal Expansion ◽  
Cold Climate ◽  
Cyanate Ester ◽  
Three Point Bending ◽  
Reinforced Plastic ◽  
Climatic Testing

The residual stresses in carbon fiber reinforced plastic (CFRP), based on VTkU-2.200 carbon fiber and VSC-14 cyanate ester resin, modified by nanoscale additives (astralen) were studied. Natural exposure was performed in a moderately cold climate. The influence of nanoadditives on mechanical and physical CFRP’s properties after 9 months of climatic testing was studied using the following properties: three-point bending strength, compression strength, coefficient of linear thermal expansion, glass transition temperature and residual stresses parameters. The increase of residual stresses after climatic testing was revealed.

ASSESSMENT OF THE STABILITY OF CARBON FIBER TO THE ACTION OF TRANSVERSE LOADS TAKING INTO ACCOUNT TIME AND CLIMATE FACTORS

2021 ◽  
pp. 3-11
Author(s):  
I. V. Zlobina
Keyword(s):  
Electromagnetic Field ◽  
Carbon Fiber ◽  
Environmental Factors ◽  
Bending Strength ◽  
Negative Influence ◽  
Strengthening Effect ◽  
Functional Dependencies ◽  
Experimental Conditions ◽  
Term Operation ◽  
The Stability

The relevance of research in the development of physical methods for increasing the stability of products made of polymer composite materials (PCM) to the influence of environmental factors, taking into account its duration, is shown. The influence of exposure of carbon fiber samples on an epoxy matrix in the natural conditions of the climate zone of Saratov on the change in the limit stresses of three-point bending was studied. Comparative tests of samples premodified in a microwave electromagnetic field with a frequency of 2.45 GHz with an energy flux density (17…18)×104 µw/cm2 were performed. It is shown that the influence of environmental factors leads to a decrease in the limit stresses by (3,7…10,4) % depending on the exposure. Modification of carbon fiber in the cured state in the microwave electromagnetic field reduces the negative influence of the external environment by reducing the strength by (44.3…73) %. It was found that the strengthening effect of microwave modification increases with increasing exposure from 6 % to 11.5 % under the accepted experimental conditions, while the uniformity of the bending strength values in the batch increases significantly, which is manifested in a decrease in the coefficient of variation of limit stresses by (70.2…77.8) %. Functional dependencies in the form of 2nd-order polynomials are obtained, allowing with confidence (98…99) % predict the stability of products made of modified carbon fiber during long-term operation under the influence of environmental factors.

scholarly journals INFLUENCE OF THE TIME FACTOR ON THE EFFECTIVENESS OF THE TECHNOLOGY OF HARDENING IN THE MICROWAVE ELECTROMAGNETIC FIELD OF STRUCTURAL ELEMENTS MADE OF CARBON FIBER REINFORCED PLASTICS

2020 ◽  
pp. 18-20
Author(s):  
I. Zlobina ◽  
N. Bekrenev ◽  
I. Katsuba
Keyword(s):  
Electromagnetic Field ◽  
Carbon Fiber ◽  
Time Factor ◽  
Structural Elements ◽  
Three Point Bending ◽  
Reinforced Plastics ◽  
Production Type ◽  
Carbon Plastics ◽  
Fiber Reinforced Plastics ◽  
Structural Carbon

The article describes the results of comparative tests for three-point bending of carbon fiber samples processed in a microwave electromagnetic field after exposure for 1.5 years in a closed room of the production type. It was found that the time factor does not lead to a decrease in the strength characteristics of the treated cured carbon plastics within the studied limits. For control samples, a decrease of 10.6% was observed. The results obtained confirm the feasibility of using microwave technology as a finishing operation in the production of engineering products made of structural carbon plastics.

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