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.

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 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.

scholarly journals Degradation Behavior of Carbon Fiber Reinforced Plastic (CFRP) in Microwave Irradiation

2007 ◽  
Vol 7 (1 & 2) ◽  
pp. 157
Author(s):  
Nguyen Nguyen ◽  
Phuong Ngoc Diem ◽  
Susan A. Roces ◽  
Florinda T. Bacani ◽  
Masatoshi Kubouchi ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Microwave Irradiation ◽  
Bending Strength ◽  
Bending Test ◽  
Carbon Fiber Reinforced Plastic ◽  
Fiber Reinforced ◽  
Fiber Reinforced Plastic ◽  
Cfrp Composites ◽  
Reinforced Plastic ◽  
Carbon Fiber Reinforced

Carbon fiber reinforced plastic (CFRP) composites are being used increasingly not only in strengthening structures of civil infrastructures and aerospace or automotive industries but also in many applications such as in medical fields or chemical plants. The present study relates to resin compositions having beneficial physical and mechanical properties, which may include improved resistance to delamination. This study focused on the different behaviors of CFRP composites when subjected to microwave irradiation. Based on the results of the 3-point bending test and SEM images, the delamination tendencies of breaking the CFRP under microwave were discussed. The results can be summarized as follows: (1) CFRP can be degraded under microwave irradiation; (2) two delamination tendency curves of CFRP by microwave irradiation were observed; (3) only the bending strength values of CFRP decreased with increasing microwave power and residence time; and, (4) the degradation of CFRP by microwave was limited.

scholarly journals Interlaminar Shear Behavior of Laminated Carbon Fiber Reinforced Plastic from Microscale Strain Distributions Measured by Sampling Moire Technique

2018 ◽  
Author(s):  
Qinghua Wang ◽  
Shien RI ◽  
Hiroshi Tsuda ◽  
Yosuke Takashita ◽  
Ryuta Kitamura ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Shear Strain ◽  
Shear Behavior ◽  
Carbon Fiber Reinforced Plastic ◽  
Fiber Reinforced ◽  
Three Point Bending ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic ◽  
Carbon Fiber Reinforced ◽  
Interlaminar Shear

The interlaminar shear behavior of a [±45°] laminated carbon fiber reinforced plastic (CFRP) specimen was investigated utilizing microscale strain mapping in a wide field of view. A three-point bending device was developed under a laser scanning microscope, and the full-field strain distributions including normal, shear and principal strains of CFRP in a three-point bending test were measured using a developed sampling Moire technique. The microscale shear strain concentrations at interfaces between each two adjacent layers were successfully detected and found to be positive-negative alternately distributed before damage occurrence. The 45° layers slipped to the right relative to the -45° layers, visualized from the revised Moire phases and shear strain distributions of the angle-ply CFRP under different loads. The absolute values of the shear strain at interfaces gradually rose with the increase of the bending load, and the sudden decrease of the shear strain peak value implied the occurrence of interlaminar damage. The evolution of the shear strain concentrations is useful in the quantitative evaluation of the potential interlaminar shear failure.

Transverse Bending and Axial Compressing Mechanical Characteristics of Carbon Fiber Reinforced Plastic Sandwich Laminated Square Tubes

2020 ◽  
Vol 12 (9) ◽  
pp. 1289-1299
Author(s):  
Xiujie Zhu ◽  
Chao Xiong ◽  
Junhui Yin ◽  
Dejun Yin ◽  
Huiyong Deng
Keyword(s):  
Carbon Fiber ◽  
Bearing Capacity ◽  
Aluminum Foam ◽  
Carbon Fiber Reinforced Plastic ◽  
Three Point Bending ◽  
Fiber Reinforced Plastic ◽  
Transverse Bending ◽  
Reinforced Plastic ◽  
Aluminum Honeycomb ◽  
Stiffness Characteristics

The transverse bending and axial compressing mechanical properties of carbon fiber reinforced plastic (CFRP) sandwich laminated square tubes with two kinds of cores, aluminum honeycomb and aluminum foam, respectively, were studied. The failure mechanism and damage processes of the two different CFRP sandwich laminated square tubes were studied by three-point bending and axial compressing experiments, comparing to CFRP hollow laminated square tube. The three-point bending process of CFRP sandwich laminated square tubes were also simulated in ABAQUS/Explicit and the failure mechanism and modes were deeply analyzed. The analytical model of composite laminated box beam using shear-deformable beam theory was extended to calculate the stiffness characteristics of CFRP sandwich laminated square tubes. The variation of bending, axial and shear stiffness in the linear elastic range were predicted. The results show that, after reaching the peak of three-point bending load, the bearing capacity of CFRP hollow laminated square tube reduced greatly due to the buckling instability of the two vertical sides, while that of the CFRP sandwich laminated square tubes were still considerable. A sudden strength damage occurred in the CFRP sandwich laminated tubes under the axial load, and the sandwich panels could slow down the drop of bearing capacity and increase the energy absorption. The load–displacement histories of numerical simulation and experimental result were in good agreement. The differences between analytically calculated and experimental measured stiffness characteristics were within 6.5%. The bending stiffness and axial stiffness of CFRP sandwich laminated tubes are large when the ply angle in the range from 0 to 45 degrees. Compared with the CFRP aluminum foam sandwich square tube, the specific stiffness and specific energy absorption of CFRP aluminum honeycomb sandwich square tube were higher but the energy absorbed was inferior.

scholarly journals Interlaminar Shear Behavior of Laminated Carbon Fiber Reinforced Plastic from Microscale Strain Distributions Measured by Sampling Moiré Technique

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1684 ◽  
Author(s):  
Qinghua Wang ◽  
Shien Ri ◽  
Hiroshi Tsuda ◽  
Yosuke Takashita ◽  
Ryuta Kitamura ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Shear Strain ◽  
Shear Behavior ◽  
Carbon Fiber Reinforced Plastic ◽  
Fiber Reinforced ◽  
Three Point Bending ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic ◽  
Carbon Fiber Reinforced ◽  
Interlaminar Shear

In this article, the interlaminar shear behavior of a [±45°]4s laminated carbon fiber reinforced plastic (CFRP) specimen is investigated, by utilizing microscale strain mapping in a wide field of view. A three-point bending device is developed under a laser scanning microscope, and the full-field strain distributions, including normal, shear and principal strains on the cross section of CFRP, in a three-point bending test, are measured using a developed sampling Moiré technique. The microscale shear strain concentrations at interfaces between each two adjacent layers were successfully detected and found to be positive-negative alternately distributed before damage occurrence. The 45° layers slipped to the right relative to the −45° layers, visualized from the revised Moiré phases, and shear strain distributions of the angle-ply CFRP under different loads. The absolute values of the shear strain at interfaces gradually rose with the increase of the bending load, and the sudden decrease of the shear strain peak value implied the occurrence of interlaminar damage. The evolution of the shear strain concentrations is useful in the quantitative evaluation of the potential interlaminar shear failure.

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