Long-term moisture effects on the interfacial shear strength between surface treated carbon fiber and epoxy matrix

Yu, Bin; Jiang, Zhenyu; Yang, Jinglei

doi:10.1016/j.compositesa.2015.08.027

Cited by 61 publications

(18 citation statements)

References 45 publications

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“…．さらに近年では，潮流発電ユニットやメガフロートなどの大型海洋構造物への適用が期待され，今後も海水環境下における FRP の用途の拡大が見込まれている )．しかし，実際の海水環境は腐食環境であると同時に，波や潮流などの繰り返し荷重，水圧や構造物の自重などの定荷重負荷といった様々な力学的因子が加わる厳しい環境となっている (Davies and Choqueuse, 2003)．また，海洋構造物の大型化・複雑化に伴い地上同様の定期メンテナンス実施は困難となる．以上のことから，海水環境下における FRP の長期耐久性評価の必要性が高まっている．海水環境下においては，FRP の構成基材である強化繊維や母材樹脂，繊維/樹脂界面の劣化が生じることが知られているが，それらの劣化挙動は各構成基材によって大きく異なる．例えば，海水浸漬後のガラス繊維及び炭素繊維に対する繊維強度測定及び表面観察では，ガラス繊維は繊維表面の腐食やそれに起因した繊維直径の減少が発生し，繊維強度も大幅に低下する一方で，炭素繊維はほとんど海水浸漬の影響を受けないことが確認されている , Joung-Man Park et al, 2016．また，代表的な母材樹脂であるエポキシ樹脂，ビニルエステル樹脂ならびにポリエステル樹脂に対する吸水特性及び熱物性・赤外線分光法(FTIR)の結果などから，ビニルエステル樹脂の高い耐腐食性が確認されている , Visco et al, 2012．さらに，繊維/樹脂界面においては，水分が拡散すると繊維表面に塗布されているシランカップリング剤の加水分解反応発生や繊維/樹脂境界の水素結合形成によって界面せん断強度が低下し，また吸水時における繊維と樹脂の体積膨張率の差異による界面での応力発生に起因して， FRP の強度低下が生じると示唆されている (中西, 幾田 1996, Yu et al, 2015, Ray, 2006．つまり，海水環境下における FRP の劣化挙動は構成基材である強化繊維と母材樹脂の組み合わせや積層構成に大きく左右される．また，構成基材の劣化に伴う FRP の機械的特性の低下についても過去いくつかの報告がある．海水浸漬させた FRP に対して各物性値を取得したところ，浸漬後では静的引張強度，静的曲げ強度，弾性率，界面せん断強度がそれぞれ低下しており，また浸漬時間が長いほど各物性値の低下を確認している , 1986 No immersion specimen 300h immersion specimen Fig. 3 Seawater immersion curves of dumbbell shaped specimen and coupon specimen.…”

Section: て採用されている(Royunclassified

Evaluation of static tensile strength and fatigue strength degradation of plain woven CFRP laminates under seawater immersion

Koshima

Kajii

Hosoi

et al. 2019

Transactions of the JSME (In Japanese)

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Carbon fiber reinforced plastics (CFRPs) are widely used as components of marine structures. Thus, it is important to understand the degradation of the mechanical properties and its mechanism under seawater immersion. The object of this study is the influence of seawater immersion on the mechanical properties of plain woven CFRP laminates. Static tensile test and tensile fatigue test were carried out on the CFRP immersed different time under seawater for 300, 2500 and 5400 hours. The mechanical properties immersed for 300 hours was almost the same value compared with those of no immersion. However, the tensile strength immersed for both 2500 and 5400 hours reduced by 22.5% compared with that of no immersion. Then, from the fatigue results, in the low-cycle fatigue region, the fatigue strengths decreased as immersion time was longer, on the other hand, in the high-cycle fatigue region, the fatigue strength did not change significantly regardless of immersion time. As a result, the inclination of S-N curves became gentle as immersion time was longer. From observation of fracture surfaces by scanning electron microscopy (SEM), it was shown that the fiber/matrix interface deteriorated remarkably after seawater immersion. Moreover, the difference of damage growth behaviors due to immersed in seawater under fatigue loading was investigated using soft X-ray photography. On specimen immersed in seawater, the accumulation of damage expanded more widely due to interface degradation compared with that of no immersion. Considering these results, it was suggested that the static tensile strength depended on load transmission efficiency between fiber and matrix, on the other hand, the fatigue strength in high cycle fatigue region depended on the strength of fiber along 0° that had small influences by seawater immersion.

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Section: て採用されている(Royunclassified

Evaluation of static tensile strength and fatigue strength degradation of plain woven CFRP laminates under seawater immersion

Koshima

Kajii

Hosoi

et al. 2019

Transactions of the JSME (In Japanese)

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“…Carbon fiber reinforced polymer (CFRP), a light-weight, high-strength material, has been extensively applied in different engineering fields, is easy to process and is suitable for simple mass production. [1][2][3][4][5][6] As a well-known optimum material for cryotanks, capable of fuel storage at extreme cryogenic temperatures (LH 2 and LO 2 , −183 C or even lower), CFRPs have been employed in primary and secondary structural components of launch vehicles in the aerospace industry. [7,8] Composite cryotanks filled with cryogenic propellants (fueling/ refueling) are required to be resistant to dramatic temperature change as well as long cryogenic temperature exposure.…”

Section: Introductionmentioning

confidence: 99%

Enhancement of the cryogenic‐interfacial‐strength of carbon fiber composites by chemical grafting of graphene oxide/attapulgite on T300

Yan

Chu

et al. 2020

Polymer Composites

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A mismatch between the expansion coefficients of carbon fiber (CF, T300) and resin causes thermal deterioration at the interface of composite cryotanks. This study presents an effective method to enhance the cryogenic interfacial properties of a T300/epoxy (EP) composite, in which graphene oxide (GO)/attapulgite (ATP) hierarchical structures are chemically grafted onto the surface of T300. GO and ATP were sequentially assembled on the T300 surface, which changed the morphology of T300 and optimized the interfacial wettability of T300/EP. Surface topography and chemical bonding of grafted T300 fibers (T300-GO-ATP) were evaluated by SEM and XPS, respectively. Considering the functioning conditions of composite cryotanks, three cryogenic interfacial testing conditions were designed for the T300-GO-ATP/EP composites: −196 C, cryogenic cycling (from RT to −196 C), and immersion in liquid nitrogen (LN 2). The interfacial shear strength (IFSS) of T300-GO-ATP/EP composite at −196 C was 88.3 MPa, 53.1% stronger than that of T300/EP (57.6 MPa). Likewise, the IFSS of T300-GO-ATP/EP composites was tested under cryogenic cycling/immersion in LN 2 , which increased remarkably comparing to those of T300/EP under the same conditions. Results shows that GO/ATP suppress interfacial cracking and enhances the interfacial bonding of T300/EP at cryogenic temperatures through chemical bonding and nanointerlocking.

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“…Different authors have performed numerical and experimental studies related with IFSS performance, searching for improvements in results and evaluating the influence in different parameters, specifically in the matrix properties. 3–9 On the other hand, out-of-plane properties are determined by interlaminar characteristics. The interlaminar zone depends on the matrix and fiber properties, as also ply orientation between two consecutive plies 10 and the interlaminar distances, which are associated with the fiber volume fraction.…”

Section: Introductionmentioning

confidence: 99%

A study of interlaminar properties for a unidirectional glass fiber reinforced epoxy composite

Pincheira

Ferrada

Hinojosa

et al. 2018

Proceedings of the IMechE

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In this work, a numerical-experimental study of the interlaminar zone for an unidirectional glass fiber reinforced epoxy composite is carried out in order to predict the load-displacement curves of a double cantilever beam test. First, an experimental mechanical characterization of the laminated composite was made through quasi-static in-plane tensile and bending tests and out-of-plane delamination tests (i.e. double cantilever beam tests or opening mode I). The main results have shown that the elastic module in the fiber direction is E 1 ¼ 32.1 GPa and the fracture process is characterized by a critical energy release rate G IC ¼ 1466 N/m. In order to be able to predict delamination using finite element analysis, a bilinear cohesive zone model is adopted. This law has two parameters-the initial stiffnessK and the critical traction t n0-to be fit for reducing the distance between numerical and experimental double cantilever beam load-displacement curves. That means an optimization problem, which is here solved by proposing a very simple and cheap three-step procedure, avoiding expensive three-dimensional simulations: (i) the numerical double cantilever beam test is coded in the OCTAVE software using one-dimensional beam elements and the bilinear cohesive zone model; (ii) several onedimensional simulations are performed varying at the cohesive law's parameters in order to build the objective function; and (iii) a genetic algorithm from the Scilab optimization toolbox is then used to determine the interface's parameters minimizing the objective function. This method has proposedK ¼ 2.74 Â 10 14 N/m 3 and t n0 ¼ 1.99 MPa as the best parameters fitting the curves. Finally, the identified bilinear cohesive law's parameters are used to carry out a full three-dimensional finite element analysis simulation in ANSYS, showing the same response than the simplified beam code, but with the possibility to obtain more accurate information about the fracture process (e.g. the shape of the process zone) or to use more complicated geometries or boundary conditions. In this work, we show the ability to predict the material behavior through different methods, using the best characteristics of each one.

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Long-term moisture effects on the interfacial shear strength between surface treated carbon fiber and epoxy matrix

Cited by 61 publications

References 45 publications

Evaluation of static tensile strength and fatigue strength degradation of plain woven CFRP laminates under seawater immersion

Evaluation of static tensile strength and fatigue strength degradation of plain woven CFRP laminates under seawater immersion

Enhancement of the cryogenic‐interfacial‐strength of carbon fiber composites by chemical grafting of graphene oxide/attapulgite on T300

A study of interlaminar properties for a unidirectional glass fiber reinforced epoxy composite

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