Fabrication, characterization and mechanical testing of carbon fiber sandwich composites with nanoparticle included polyurethane adhesives

2021 ◽  
pp. 002199832110588
Author(s):  
Mehmet Emin Çetin
Keyword(s):  
Carbon Fiber ◽  
Composite Structures ◽  
Bending Strength ◽  
Mechanical Performance ◽  
Synergistic Effects ◽  
Sandwich Panels ◽  
Sandwich Composite ◽  
Scanning Calorimetry ◽  
Aluminum Honeycomb ◽  
Out Of Autoclave

In honeycomb core and composite face sheet sandwich panels, it is essential to understand the bonding characteristics of adhesive in relevance with its properties to observe synergistic effects of reinforcing nanoparticles such as multi-walled carbon nanotubes (MWCNTs). This study investigates the effects of MWCNT inclusion on polyurethane (PU) adhesive, which directly affects sandwich structures' structural and mechanical performance. MWCNTs are added to PU adhesive up to 0.2%, and their RAMAN spectroscopic analysis, Fourier transform infrared spectroscopy (FT-IR), thermo-gravimetric analyses (TGA) and differential-scanning calorimetry analyses (DSC) are evaluated. Aluminum honeycomb carbon-fiber-reinforced composite (CFRC) sandwich panels are fabricated using an out-of-autoclave manufacturing process. Carbon-fiber prepreg is used for top/bottom face sheets. Mechanical strength of face/core bonding evaluated as a function of MWCNT addition and core cell sizes. Manufactured sandwich composite structures are investigated for flat-wise tensile strength and three-point bending strength. Results show that MWCNT reinforcement to PU adhesive and lower cell size increases bending and flat-wise tensile resistances.

Comparison and characterization of discontinuous carbon fiber liquid-molded nylon to hydroentanglement/compression-molded composites

2019 ◽  
Vol 33 (8) ◽  
pp. 1078-1093 ◽  
Author(s):  
Siddhartha Brahma ◽  
Selvum Pillay ◽  
Haibin Ning
Keyword(s):  
Carbon Fiber ◽  
Mechanical Performance ◽  
Weight Fraction ◽  
Polyamide 6 ◽  
Compression Molding ◽  
Fiber Composites ◽  
Strength Properties ◽  
Processing Temperature ◽  
Carbon Fiber Composites ◽  
Scanning Calorimetry

This article looks at liquid molding of polyamide 6 (PA6) via vacuum assisted resin transfer molding (VARTM) of discontinuous recycled carbon fiber composites. Its mechanical, thermal, and optical characterization is compared to hydroentanglement/compression molding. Liquid-molded composites show consistent improvement in their tensile and impact properties at three different weight fractions in comparison to hydroentanglement/compression molding. There was roughly a 10 and 13% increase in its tensile strength, modulus, and impact strength properties at 30 and 40% weight fractions and almost a 120% increase at 50% weight fraction. Fourier-transform infrared spectroscopy and differential scanning calorimetry data show that the caprolactam was synthesized to PA6 and was comparable to commercial grade PA6 used in this research. Scanning electron microscopy studies show poor wet out in the case of hydroentanglement/compression molding as compared to VARTM. The combination of better mechanical performance and lower processing temperature (165°C) shows promise in being a viable method to process PA6-based recycled fiber composites.

scholarly journals Effect of Submicron Glass Fiber Modification on Mechanical Properties of Short Carbon Fiber Reinforced Polymer Composite with Different Fiber Length

2020 ◽  
Vol 4 (1) ◽  
pp. 5
Author(s):  
Nhan Thi Thanh Nguyen ◽  
Obunai Kiyotaka ◽  
Okubo Kazuya ◽  
Fujii Toru ◽  
Shibata Ou ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Fiber ◽  
Glass Fiber ◽  
Fiber Length ◽  
Bending Strength ◽  
Mechanical Performance ◽  
Volume Fraction ◽  
Fiber Concentration ◽  
Static Tests ◽  
The Impact

In this research, three kinds of carbon fiber (CF) with lengths of 1, 3, and 25 mm were prepared for processing composite. The effect of submicron glass fiber addition (sGF) on mechanical properties of composites with different CF lengths was investigated and compared throughout static tests (i.e., bending, tensile, and impact), as well as the tension-tension fatigue test. The strengths of composites increased with the increase of CF length. However, there was a significant improvement when the fiber length changed from 1 to 3 mm. The mechanical performance of 3 and 25 mm was almost the same when having an equal volume fraction, except for the impact resistance. Comparing the static strengths when varying the sGF content, an improvement of bending strength was confirmed when sGF was added into 1 mm composite due to toughened matrix. However, when longer fiber was used and fiber concentration was high, mechanical properties of composite were almost dependent on the CF. Therefore, the modification effect of matrix due to sGF addition disappeared. In contrast to the static strengths, the fatigue durability of composites increased proportionally to the content of glass fiber in the matrix, regardless to CF length.

scholarly journals Curing Kinetics, Mechanical Properties and Thermomechanical Analysis of Carbon Fiber/epoxy Resin Laminates with Different Ply Orientations

2021 ◽  
Author(s):  
Chenglin Zhang ◽  
Guohua Gu ◽  
Shuhua Dong ◽  
Zhitao Lin ◽  
Chuncheng Wei ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Impact Strength ◽  
Epoxy Resin ◽  
Composite Laminates ◽  
Bending Strength ◽  
Fiber Composite ◽  
Curing Process ◽  
Scanning Calorimetry ◽  
The Impact ◽  
Carbon Fiber Epoxy

Abstract In this study, the nonisothermal differential scanning calorimetry (DSC) was carried out to evaluate the curing reaction of fiber/epoxy laminates. The optimal curing process of the prepreg was obtained by T-β extrapolation method and nth-order reaction curing kinetic equation. The bending strength, impact strength and thermodynamic properties of the composite laminates with different ply orientations were investigated, respectively. The results show that the apparent activation energy and the reaction order of the prepregs are 82.89 kJ/mol and 0.92, respectively. The curing process of carbon fiber/epoxy resin prepreg is 130 ℃ /60min + 160 ℃/30 min. The bending strength of [0]10 laminate is 1948.3 MPa, which is 11.8 times higher than that of [+ 45/-45]5s laminate, and 96.4% higher than that of [0/90]5s laminate. The impact strength of [0]10 laminate is higher than that of [+ 45/-45]5s and [0/90]5s laminates. The glass transition temperature (Tg) of the laminates is 142 ~ 146 ℃, and the loss factor of [0]10 laminate is significantly higher than that of [+ 45/-45]5s and [0/90]5s laminates. This research provides a theoretical basis for the further application of prepregs to fiber composite materials.

Direct Write Additive Manufacturing of High-Strength, Short Fiber Reinforced Sandwich Panels

2020 ◽  
Author(s):  
Nashat Nawafleh ◽  
Emrah Celik
Keyword(s):  
Additive Manufacturing ◽  
Carbon Fiber ◽  
Mechanical Performance ◽  
Sandwich Panels ◽  
High Strength ◽  
Direct Write ◽  
Fiber Reinforced ◽  
Short Carbon Fiber ◽  
Carbon Fiber Reinforced ◽  
Short Carbon

Abstract Additive manufacturing (AM) is a novel technology which allows fabrication of complex geometries from digital representations without tooling. In addition, this technology results in low material waste, short lead times and cost reduction especially for the production of parts in low quantities. Current additive manufacturing processes developed for thermoplastic sandwich panels suffer from an unavoidable weak mechanical performance and low thermal resistance. To overcome these limitations, emphasis is paid in this study on direct write AM technology for the fabrication of short carbon fiber-reinforced sandwich panel composites. Sandwich panels using different infill densities with high strength (> 107 MPa), and high short carbon fiber volume (46%) were attained successfully. In parallel to the strength enhancement, these sandwich panels possessed reduced densities (0.72 g/cc3) due to their lightweight lattice core structures. The mechanical performance of the created sandwich panels was examined and compared to the unreinforced, base ink structures by performing compression tests. Successful fabrication and characterization of the additively manufactured thermoset-based carbon fiber reinforced, sandwich panels in this study can extend the range of applications for AM composites that require lightweight structures, high mechanical performance as well as the desired component complexity.

Waste size and lay up sequence strategy for reusing/recycling carbon fiber fabric in laminate composite: Mechanical property analysis

2021 ◽  
pp. 002199832110370
Author(s):  
Marcos Yutaka Shiino ◽  
Thais Carolina Gonçalves Cipó ◽  
Maurício Vicente Donadon ◽  
Alexei Essiptchouk
Keyword(s):  
Carbon Fiber ◽  
Mechanical Strength ◽  
Composite Structures ◽  
Bending Strength ◽  
Woven Fabrics ◽  
Bending Test ◽  
Four Point Bending ◽  
A Value ◽  
Strength Based ◽  
Pet Film

Carbon fiber fabrics have been largely used in composite structures as they provide high mechanical strength and potential weigh reduction, allowing more efficiency in product design. However, the production of the parts generates scraps that is discarded as a waste, becoming a challenge to recycle the carbon fiber with predictable mechanical strength. Within this context, this research analyzed strategies of laying up carbon woven fabrics based scraps, in order to reach a desirable mechanical properties in bending loading. Three types of laminates were manufactured using varied fabric size and number of discontinuities in the layup combined with polyethylene terephthalate (PET) film as a matrix. The obtained composites were tested under four-point-bending test and an energy-strength based analysis was conducted. This analysis explained a strategic position of fabric scrap to maximize the bending strength: providing a value of 106.33 MPa for a composite with high number of discontinuities against 83.11 MPa for another with less discontinuity.

Trial Fabrication of Carbon Fiber-Reinforced Thermoplastic Honeycomb Sandwich Materials

2018 ◽  
Vol 774 ◽  
pp. 25-30
Author(s):  
Hitoshi Takagi ◽  
Kenya Nishimura ◽  
Antonio N. Nakagaito
Keyword(s):  
Carbon Fiber ◽  
Mechanical Performance ◽  
Sandwich Panels ◽  
Fiber Reinforced ◽  
Honeycomb Core ◽  
Honeycomb Sandwich ◽  
Carbon Fiber Reinforced ◽  
Honeycomb Cores ◽  
Flexural Tests ◽  
Sandwich Materials

This paper deals with a new fabrication technique of carbon fiber-reinforced thermoplastic (CFRTP) honeycomb cores and all-CFRTP honeycomb sandwich panels. The CFRTP core was made of plane woven carbon fiber-reinforced polypropylene prepreg sheets. The stacked CFRTP prepreg sheets were periodically hot-pressed at the node locations, and then expanded to form an all-CFRP honeycomb core. The resultant CFRTP honeycomb cores were glued with the same polypropylene-based plain-woven CFRTP skin plates. The mechanical performance of the all-CFRTP honeycomb sandwich panels was evaluated by flexural tests. The experimental results showed the effectiveness of proposed all-CFRTP sandwich panels.

scholarly journals Development of a Vibration Technique Based on Geometric Optimization for Fatigue Life Evaluation of Sandwich Composite Structures

2021 ◽  
Vol 12 (1) ◽  
pp. 16
Author(s):  
Marco Menegozzo ◽  
Frederick A. Just-Agosto ◽  
David Serrano Acevedo ◽  
Basir Shafiq ◽  
Andrés Cecchini ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Composite Structures ◽  
Sandwich Panels ◽  
Cost Effective ◽  
Fatigue Tests ◽  
Geometric Optimization ◽  
Bending Test ◽  
Sandwich Composite ◽  
Vibration Technique ◽  
Stress Ratios

A major obstacle to obtaining cost-effective experimental data on the fatigue life of sandwich panels is the prohibitive amount of time and cost required to carry out millions of cycles. On the other hand, vibration techniques applied to sandwich geometries fail to match the stress patterns that are obtained from standard flexural fatigue tests. To overcome such limitations, a vibration-based fatigue technique is proposed, which entails the use of sandwich specimens whose geometries are optimized to reproduce the stress distribution observed during three point bend loading while vibrating at the first resonant frequency. The proposed vibration technique was experimentally validated. The results, compared with the average number of cycles to failure at different stress ratios obtained via the Three-Point Bending test, showed high levels of accuracy. The proposed method is robust and time effective and indicates the possibility of attaining fatigue lifetime prediction of a wide class of composite elements, such as sandwich panels.

scholarly journals Design, Manufacturing, and Characterization of Hybrid Carbon/Hemp Sandwich Panels

2021 ◽  
Author(s):  
Luca Boccarusso ◽  
Fulvio Pinto ◽  
Stefano Cuomo ◽  
Dario De Fazio ◽  
Kostas Myronidis ◽  
...  
Keyword(s):  
Composite Structures ◽  
Failure Modes ◽  
Sandwich Panels ◽  
Industrial Applications ◽  
Low Velocity Impact ◽  
Sandwich Composite ◽  
Continuous Manufacturing ◽  
Low Velocity ◽  
Impact Compression

AbstractAdvanced sandwich composite structures that incorporate foams or honeycombs as core materials, have been extensively investigated and used in various applications. One of the major limitations of the conventional materials used is their weak impact resistance and their end-of-life recyclability and overall sustainability. This paper is focused on the study of the production and mechanical characterization of hybrid sandwich panels using hemp bi-grid cores that were manufactured with an ad hoc continuous manufacturing process. Bi-grid structures were stratified in multiple layers, resulting in cores with different thicknesses and planar density. Sandwich panels made with carbon fibers skins were then subjected to Low Velocity Impact, compression and indentation and the damaged panels were investigated via CT-Scan. Results show that the high tailorability of the failure modes and the very good energy absorption properties of the hybrid material open new exciting perspectives for the development of new sandwich structures that can extend the use of natural fibers into several industrial applications.

scholarly journals Bonded Repair Optimization of Cracked Aluminum Alloy Plate by Microwave Cured Carbon-Aramid Fiber/Epoxy Sandwich Composite Patch

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1655 ◽  
Author(s):  
Xiaoyan Liu ◽  
Jiacheng Wu ◽  
Jiaojiao Xi ◽  
Zhiqiang Yu
Keyword(s):  
Aluminum Alloy ◽  
Carbon Fiber ◽  
Mechanical Performance ◽  
Aramid Fiber ◽  
Sandwich Composite ◽  
Fiber Reinforced ◽  
Alloy Plate ◽  
Bending Performance ◽  
Bonded Repair ◽  
Aluminum Alloy Plate

Fiber-reinforced epoxy sandwich composites, which were designed as the bonded repair patches to better recover the mechanical performance of a central cracked aluminum alloy plate, were layered by carbon and aramid fiber layers jointly and cured by microwave method in this study. The static tensile and bending properties of both carbon-aramid fiber/epoxy sandwich composite patches and the cracked aluminum alloy plates after bonded repair were systematically investigated. By comparing the mechanical performance with traditional single carbon-fiber-reinforced composite patches, it can be found that the bending performance of carbon-aramid fiber sandwich composite patches was effectively improved after incorporation of flexible aramid fiber layers into the carbon fiber layers, but the tensile strength of sandwich composite patches was weakened to some extent. Especially, the sandwich patches with 3 fiber layers exhibited better tensile and bending performance in comparison to patches of 5 and 7 fiber layers. The optimized 3-layer carbon-aramid fiber sandwich patch repaired plate recovered 86% and 190% of the tensile and bending performance in comparison to the uncracked ones, respectively, showing a considerable repair majorization effect for the cracked aluminum alloy plate.

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