Repair and cryogenic mechanical properties with resin film infused (RFI) GFRP in out-of-autoclave processing

2020 ◽  
Vol 34 (07n09) ◽  
pp. 2040014
Author(s):  
Yun-Hae Kim ◽  
Kyo-Moon Lee ◽  
Seong-Jae Park ◽  
Kyung-In Jo ◽  
Soo-Jeong Park

Prepreg technology generates air pockets at the interface of laminates under heating and pressurization. The air pockets cause defects in the through-thickness direction. This includes poor adhesion between layers, which degrades material properties. Therefore, in this study, cryogenic mechanical properties were compared to obtain uniform properties by using prepreg laminated and resin film infused glass fiber reinforced plastic (GFRP) composites (“PP-only” and “RF-only”, respectively) while maintaining the constituent contents of the fiber and polymer. Moreover, stepped repair was applied to extend the life of composites. The results demonstrated that the stiffness of the composites improved, and the brittleness increased in cryogenic environments. In the case of PP-only, numerous voids were observed inside the polymer, which showed higher bending strength than RF-only; however, it exhibited significantly lower interfacial bonding strength. When applied to secondary bonding of stepped repair, RF-only as repair layers showed high strength recovery rate in homogeneous materials, and not in heterogeneous materials. In contrast, the high strength PP-only as a parent material and RF-only as repair layers showed relatively good interfacial bonding strength due to primary damage in the PP of a parent material. Hence, the RF-only can be considered useful as a repair material.

2014 ◽  
Vol 989-994 ◽  
pp. 177-180
Author(s):  
Hao Yang ◽  
Jian Hua Zhang ◽  
Guo Yan Sun ◽  
Yi Zhang

For the characteristic that the mechanical properties of resin composite are lower than cast iron, steel fibers are used to improve its properties in this paper. A weak interfacial bonding strength between steel fibers and resin indicates that steel fibers’ property cannot perform well in the polymer. In order to improve the interfacial bonding strength, four methods of surface treatment, phosphating, acid pickling, oxidation, and coupling are applied to steel fibers, and the corresponding pull-off tests are carried out to compare with untreated steel fibers. Research results show that the maximum interfacial bonding strength is increased by 45.1% after coupling treatment.


2021 ◽  
Vol 10 (1) ◽  
pp. 282-291
Author(s):  
Xingxing Chen ◽  
Ying Li ◽  
Ying Wang ◽  
Dingquan Song ◽  
Zuowan Zhou ◽  
...  

Abstract Nano molding technology (NMT) has shown great potential in the preparation of metal/resin composites, which can integrate resin and metal into a lightweight, high-strength metal matrix composite. However, due to the poor interfacial bonding strength between metal and polymer, the application of the metal/polymer composites is limited. In this paper, we proposed a novel method to improve the bonding strength between Fe–Co–Ni alloy and epoxy resin by Nano Perfusion Technology (NPT), featuring in situ growth of carbon nanotubes (CNTs) in the pores on anodized Fe–Co–Ni alloy porous surface, followed by a perfusion of epoxy resin throughout the pores that had been in situ grown CNTs. Due to the “anchor effect” of CNTs, the bonding strength between the epoxy and the alloy matrix is improved. The results showed that the interfacial bonding between the in situ CNTs-modified alloy and the resin was significantly improved compared to the metal-resin composites surface treated with T-treatment in traditional method of NMT. The maximum interfacial bonding force of the alloy-CNTs/epoxy composite reached up to 691.80 N, which was 460, 315, and 267% higher than those by mechanical treatment, without CNTs and T-treatment, respectively. This work provides a new approach to protect metals or alloys from environmental corrosion, impact damage, and so on.


2000 ◽  
Vol 654 ◽  
Author(s):  
Youngman Kim ◽  
Jong-Hoon Jeong ◽  
Jae-Chul Lee

AbstractMetal matrix composites (MMC's) are known to have wide applications in parts of transportation devices such as automobiles and aircraft. Al matrix composites using SiC particles as reinforcements are especially spotlighted because of low cost, superior specific modulus, specific strength, wear resistance and high temperature stability. However, Al4C3 formed by the interfacial reaction between Al and SiC weakens the interfacial bonding strength. It is also known to be unstable in the water-soluble atmosphere.In this study, the passive oxidation of SiC powder is used as protective layer against the reaction between the Al matrix and the SiC particle. We investigated the changes in interfacial product of the composites and mechanical properties such as interfacial bonding strength, and tensile strength in terms of the oxidized layer thickness of the reinforcement.


2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Xiaofei Wang ◽  
Jiangbei Yao ◽  
Xinwei Li ◽  
Yinchuan Guo ◽  
Aiqin Shen ◽  
...  

With heavy modern traffic and natural factors, cement concrete pavement cracks have become increasingly serious. However, most existing inorganic repair materials for cement concrete pavement cracks have low interfacial bonding strength. Ultrafine cement, silica fume (SF), and other admixtures, which are superfine and used to repair fine early cracks, are prepared as the mending material in our research. Compression strength, bending strength, and interfacial bonding strength are studied, and modification mechanisms are discovered by using a powder X-ray diffraction test, thermal analysis, and micromorphology observation. The result shows that mechanical strength of the stable period is improved with the right amount of mixing of SF, which leads to secondary pozzolanic reaction and makes the microstructure of the paste denser. Meanwhile, a large amount of Ca(OH)2 and water in the interface area are consumed by the secondary pozzolanic reaction, which brings out good interfacial effects with no water film between the new paste and existing concrete. Our experiments show that the pastes with 3–5% SF have better bending strength (15%∼17% improvement) and compressive strength (7%∼9% improvement). Interfacial bonding strength is also increased with a certain amount of SF. Tensile shear bonding strength has been improved more than 4 times when SF dosage is more than 3%. Thus, we recommend a paste with 5% SF as the best mixture to be used to repair cracks.


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