• Title/Summary/Keyword: Non-woven carbon tissue

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Effects of Non-Woven Tissue on the Mechanical Behavior of Angle-Ply Laminates (부직포가 예각 적층판의 기계적 거동에 미치는 효과)

  • 정성균
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.10 no.6
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    • pp.109-115
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    • 2001
  • This paper investigates the mechanical characteristics of angle-ply laminates with non-woven carbon tissue. The lami- nates were made by inserting non-woven carbon tissue at the interface. Specimens were rounded near the tabs by grinding and polishing to reduce the stress concentration. Cyclic loads were applied to the specimens and the stress and fatigue life curves were obtained. The matrix crack density was also evaluated to check the effects of non-woven carbon tissue on the fracture resistance of composite laminates. C-Sean technique was used to evaluate the delamination, and SEM was used to understand the fracture mechanisms of the laminates. Experimental results show that the fatigue strength and life of composite laminates were increased by inserting non- woven carbon tissues. The results also show that the matrix crack density and delamination area were reduced by inserting non-woven carbon tissues.

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Effect of non-woven tissues on interlaminar fracture toughness of composite laminate (부직포가 복합적층판의 층간파괴인성에 미치는 효과)

  • 김영배;정성균;강진식;김태형
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2000.11a
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    • pp.110-114
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    • 2000
  • The Interlaminar fracture behavior of hybrid composite with non-woven carbon tissue was investigated under Mode I (DCB) and Mode II (ENF) loading condition. Hybrid composites were manufactured by means of inserting a non-woven tissue between prepreg layers. Two kinds of specimens were prepared from [0]$_{24}$ and [$0_{12}/0_{12}$]. Where, the symbol "/" means that a non-woven carbon tissue was located at 0/0 mid-plane of the specimen. The interlaminar fracture toughness of hybrid composites was compared with that of CFRP. The fracture surfaces of the specimens were observed using optical microscope and SEM, and the failure mechanism was discussed. The hybrid laminates, which are made by inserting non-woven carbon tissue between layers, were shown to be effective to remarkably improve Mode II fracture toughness.toughness.

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Interlaminar Fracture Toughness of Hybrid Composites Inserted with Different Kinds of Non-Woven Tissues : Part I-Mode I (종류가 다른 부직포가 삽입된 하이브리드 복합재료의 층간파괴인성 : Part I-Mode I)

  • Jeong, Jong-Seol;Cheong, Seong-Kyun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.37 no.4
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    • pp.497-502
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    • 2013
  • In this study, the interlaminar fracture toughness in mode I of a hybrid composite inserted with different types of non-woven tissues was determined. The interlaminar fracture toughness in mode I is obtained by a double cantilever beam test. The experiment is performed using three types of non-woven tissues: 8 $g/m^2$ of carbon tissue, 10 $g/m^2$ of glass tissue, and 8 $g/m^2$ of polyester tissue. Considering a specimen with no non-woven tissue as a reference, the interlaminar fracture toughness in mode I of specimens inserted with non-woven carbon and glass tissues decreases by as much as 6.3% and 11.4%, respectively. However, the fracture toughness of a hybrid composite specimen inserted with non-woven polyester tissue increases by as much as 69.4%. It is considered that the specimen inserted with non-woven polyester tissue becomes cheaper, and lighter, and the value of the fracture toughness becomes much greater than that of the non-woven carbon tissue.

Mode II Interlaminar Fracture Toughness of Hybrid Composites Inserted with Different Types of Non-woven Tissues (종류가 다른 부직포가 삽입된 하이브리드 복합재료의 모드 II 층간파괴인성)

  • Jeong, Jong-Seol;Cheong, Seong-Kyun
    • Composites Research
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    • v.26 no.2
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    • pp.141-145
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    • 2013
  • The mode II interlaminar fracture toughness was evaluated for CFRP laminates with different types of nonwoven tissues and the source of increased mode II interlaminar fracture toughness was examined by SEM analysis in this paper. The interlaminar fracture toughness in mode II is obtained by an end notched flexure test. The experiment is performed using three types of non-woven tissues: 8 $g/m^2$ of carbon tissue, 10 $g/m^2$ of glass tissue, and 8 $g/m^2$ of polyester tissue. On the basis of the specimen with no non-woven tissue, interlaminar fracture toughness on mode II at specimens inserted with non-woven carbon and glass tissues and polyester tissues increases as much as 166.5% and 137.1% and 157.4% respectively. The results show that mode II interlaminar fracture toughness of CFRP laminates inserted with nonwoven tissues increased due to the fiber bridging, fiber breakage, and hackle etc. by SEM analysis.

Analysis of Shear Characteristics of Angle-Ply Laminates with Non-woven Tissue by FEM (FEM에 의한 부직포 삽입 예각 적층판의 전단특성 해석)

  • 이승환;정성균
    • Korean Journal of Crystallography
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    • v.13 no.2
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    • pp.69-72
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    • 2002
  • The interlaminar problems near the free edge of composite laminates are analyzed in this paper. CFRP specimen ([+40/-40]s) and interleaved specimen ([+40//-40]s) with non-woven carbon tissue (NWCT) are discussed under tensile loading condition. The symbol “//”means that the NWCT is located between the CFRP interfaces. The NWCT has carbon short fibers which are discretely distributed with the in-plane random orientation. It was reported/sup 3)/ that the Mode Ⅱ interlaminar fracture toughness of CFRP laminates with NWCT is increased largely and the Mode I interlaminar fracture toughness is not changed significantly. Mode Ⅲ interlaminar fracture toughness is also an important factor in composite structures. But it is not easy to experimentally investigate the Mode Ⅲ interlaminar fracture toughness. The objective of this work is to study the effect of the NWCT and to fundamentally understand the Mode Ⅲ interlaminar shear characteristics of laminated composites with NWCT in the vicinity of a free edge by using finite element method analysis.

Interlaminar Fracture Toughness of CFRP Laminates with Carbon Non-Woven Tissue Having Different Weights (무게가 상이한 탄소부직포가 삽입된 CFRP적층판의 층간파괴인성)

  • Cheong, Seong-Kyun
    • Composites Research
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    • v.22 no.2
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    • pp.43-48
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    • 2009
  • For the practical use of improved interlaminar fracture toughness by interleaving carbon non-woven tissue (CNWT), intelaminar fracture toughnesses of CFRP laminates with CNWT having different weights were experimentally investigated. A suitable weight of interleaved CNWT in CFRP laminates was discussed with Mode I and Mode II tests. Mode I and Mode II interlaminar fracture toughnesses (GIC and GIIC) were obtained by DCB and ENF tests. Six kinds of specimens with CNWT were prepared. The weights of CNWT per square meter for six types of specimens are $8g/m^2,\;10g/m^2,\;12g/m^2,\;16g/m^2,\;20g/m^2$, and $24g/m^2$, respectively. The mean GIC and GIIC values of six kinds of specimens were not substantially different from one another. Compared with the CFRP specimen, the mean GIC values of six kinds of specimens were slightly decreased. But the mean GIIC values increased tremendously at least twice by interleaving CNWT. It seems that there is no interrelationship between the interlaminar fracture toughnesses (GIC and GIIC) and the interleaving CNWT weights. Consequently, it would be desirable to use the CNWT of $8g/m^2$ among the six kinds of CNWTs to take advantage of the interlaminar fracture toughness improved by interleaving CNWT, because the CNWT of $8g/m^2$ is a lightweight and low-priced material.