• Title, Summary, Keyword: 취성기지 복합재료

Search Result 9, Processing Time 0.041 seconds

Effect of Interfacial Debonding on the Material Properties of Brittle Matrix Composites (취성기지 복합재료의 물성치에 미치는 계면분리의 영향)

  • 염영진;진민철
    • Composites Research
    • /
    • v.16 no.1
    • /
    • pp.42-49
    • /
    • 2003
  • Brittle matrix composites often have interfacial debonding between the fiber and matrix which may lead to strength and stiffness degradation. The effect of interfacial debonding and fiber volume fraction on the mechanical properties of composite material were studied by using finite element method. Firstly, the modelling of fiber and matrix constituting the composite material was simplified under some assumptions. Traction and displacement continuity conditions were imposed along the boundary of adjacent representative volume elements. In order to obtain the effective material properties of composite material, stiffness constants were inverted. Numerical values of longitudinal moduli in case of perfect bonding were compared with theoretical values obtained by rule of mixtures and yielded consistency. Material properties of composite with large debonding an81e were found to decrease even though the fiber volume fraction increased.

Reinforcing Characteristics on Volume and Shape of Ductile Short-Fiber in Brittle Matrix Composites (취성기지 복합재료에서 연성 단섬유의 함유량 및 형상에 관한 보강특성)

  • Sin, Ik-Jae;Lee, Dong-Ju
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.24 no.1
    • /
    • pp.250-258
    • /
    • 2000
  • The reinforcing effects of ductile short-fiber reinforced brittle matrix composites are studied by, measuring flexural strength, fracture toughness and impact energy as functions of fiber volume fraction and length. The parameters of fracture mechanics, K and J are applied to assess fracture toughness and bridging stress. It is found that fracture toughness is greatly, influenced by the bridging stress ill which fiber pull-out is occur. For the reinforcing effects as functions of fiber volume fraction($V_f$ = 1, 2, 3 %) and length(L = 3, 6. 10cm), the flexural strength is maximum at $V_f$ = 1% and both fracture toughness.

Interfacial Evaluation of Plasma-Treated Biodegradable Poly(p-dioxanone) Fiber/Poly(L-lactide) Composites Using Micromechanical Technique and Dynamic Contact Angle Measurement (Micromechanical 시험법과 동적접촉각 측정을 이용한 플라즈마 처리된 생분해성 Poly(p-dioxanone) 섬유강화 Poly(L-lactide) 복합재료의 계면물성 평가)

  • Park, Joung-Man;Kim, Dae-Sik;Kim, Sung-Ryong
    • Journal of Adhesion and Interface
    • /
    • v.4 no.1
    • /
    • pp.18-27
    • /
    • 2003
  • Interfacial properties and microfailure degradation mechanisms of the oxygen-plasma treated biodegradable poly(p-dioxanone) (PPDO) fiber/poly(L-lactide) (PLLA)composites were investigated for the orthopedic applications as implant materials using micromechanical technique and surface wettability measurement. PPDO fiber reinforced PLLA composite can provide good mechanical performance for long hydrolysis time. The degree of degradation for PPDO fiber and PLLA matrix was measured by thermal analysis and optical observation. IFSS and work of adhesion, $W_a$ between PPDO fiber and PLLA matrix showed the maximum at the plasma treatment time, at 60 seconds. Work of adhesion was lineally proportional to the IFSS. PPDO fiber showed ductile microfailure modes at We initial state, whereas brittle microfailure modes appeared with elapsing hydrolysis time. Interfacial properties and microfailure degradation mechanisms can be important factors to control bioabsorbable composites performance because IFSS changes with hydrolytic degradation.

  • PDF

A Study on the Interface Behavior of Aluminium Alloy Martrix Composites Reinforced with W Fiber (W 섬유강화 알루미늄합금 복합재료 계면거동에 관한 연구)

  • Jang, G.Y.;Huh, J.G.;Hyun, Ch.Y.;Kim, S.Y.
    • Journal of the Korean Society for Heat Treatment
    • /
    • v.5 no.4
    • /
    • pp.209-214
    • /
    • 1992
  • A Study on the Interface Behavior of Aluminium Alloy Matrix Composites Reinforced with W Fiber. In this study the tungsten fiber reinforced 7072 aluminium alloy martrixcomposites were fabricated using vacuum hot press. The fiber has been aligned on the aluminium alloy sheets and these sheets were bonded with diffustion at 873K and 49Mpa. The behaviors of interface layer and mechanical properites have been investigated as a function of holding time at 873K. Several compounds were formed at the interface layer. These compounds were growing in propotion to holding time. XRD analysis showed that these compounds were $WAl_{12}$ $WAl_5$. The tensile strength decreased as the heat treatment time over 10hr gradually. The ductle fractur mode was turned to brittle mode after heat treatment.

  • PDF

Interfacial Evaluation and Nondestructive Damage Sensing of Carbon Fiber Reinforced Epoxy-AT-PEI Composites using Micromechanical Test and Electrical Resistance Measurement (Micromechanical 시험법과 전기저항 측정을 이용한 탄소섬유 강화 Epoxy-AT-PEI복합재료의 비파괴적 손상 감지능 및 계면물성 평가)

  • Joung-Man Park;Dae-Sik Kim;Jin-Woo Kong;Minyoung Kim;Wonho Kim
    • Composites Research
    • /
    • v.16 no.2
    • /
    • pp.62-67
    • /
    • 2003
  • Interfacial properties and damage sensing for the carbon fiber/epoxy-amine terminated (AT)-polyetherimide (PEI) composite were performed using microdroplet test and electrical resistance measurements. As AT-PEI content increased, the fracture toughness of epoxy-AT-PEI matrix increased, and interfacial shear strength (IFSS) increased due to the improved fracture toughness by energy absorption mechanisms of AT-PEI phase. The microdroplet in the carbon fiber/neat epoxy composite showed brittle microfailure mode. At 15 phr AT-PEI content ductile microfailure mode appeared because of improved fracture toughness. After curing, the change in electrical resistance $\Delta\textrm{R}$) with increasing AT-PEI content increased gradually because of thermal shrinkage. Under cyclic stress, in the neat epoxy case the reaching time until same stress was faster and their slope was higher than those of 15 phr AT-PEI. The result obtained from electrical resistance measurements under curing process and reversible stress/strain was correspondence well with matrix toughness properties.

Optimum Conditions for Improvement of Mechanical and Interfacial Properties of Thermal Treated Pine/CFRP Composites (열처리된 Pine/탄소섬유 복합재료의 기계적 및 계면물성 향상을 위한 최적 조건)

  • Shin, Pyeong-Su;Kim, Jong-Hyun;Park, Ha-Seung;Baek, Yeong-Min;Kwon, Dong-Jun;Park, Joung-Man
    • Composites Research
    • /
    • v.30 no.4
    • /
    • pp.241-246
    • /
    • 2017
  • The brittle nature in most FRP composites is accompanying other forms of energy absorption mechanisms such as fibre-matrix interface debonding and ply delamination. It could play an important role on the energy absorption capability of composite structures. To solve the brittle nature, the adhesion between pines and composites was studied. Thermal treated pines were attached on carbon fiber reinforced polymer (CFRP) by epoxy adhesives. To find the optimum condition of thermal treatment for pine, two different thermal treatments at 160 and $200^{\circ}C$ were compared to the neat case. To evaluate mechanical and interfacial properties of pines and pine/CFRP composites, tensile, lap shear and Izod test were carried out. The bonding force of pine grains was measured by tensile test at transverse direction and the elastic wave from fracture of pines was analyzed. The mechanical, interfacial properties and bonding force at $160^{\circ}C$ treated pine were highest due to the reinforced effect of pine. However, excessive thermal treatment resulted in the degradation of hemicellulose and leads to the deterioration in mechanical and interfacial properties.

Ultra-high Temperature Ceramics-Ceramic Matrix Composites (UHTC-CMC) (섬유강화 초고온 세라믹스 복합재료(UHTC-CMC))

  • Lee, Sea-Hoon;Lun, Feng;Chung, Kyeongwoon
    • Composites Research
    • /
    • v.30 no.2
    • /
    • pp.94-101
    • /
    • 2017
  • Ultra-high temperature ceramics (UHTC) such as $ZrB_2$, ZrC, $HfB_2$, HfC and TaC has been recently actively investigated for the application as components such as nose-cone, rocket nozzle and leading edge of hypersonic systems. However, the application has been limited by various reasons. The brittleness of the materials and consequent low thermal shock resistance is one of the reasons. The property can be improved through the fabrication of ceramic matrix composites. In this paper, the concept of UHTC and the fabrication process and testing of UHTC-based ceramic matrix composites (UHTC-CMC) were briefly reviewed. Also, international activities regarding the fabrication of UHTC-CMC were summarized and a UHTC-CMC project, which was performed in Korea, was introduced.

Evaluation of Interfacial Properties on the Electrodeposited Carbon Fiber Reinforced Polyetherimide Toughened Epoxy Composites using Micromechanical Test (Micromechanical 시험법을 이용한 전기증착된 탄소섬유 강화 Polyetherimide로 강인화된 에폭시 복합재료의 계면물성 평가)

  • 박종만;김대식;공진우;김민영;김원호
    • Composites Research
    • /
    • v.15 no.3
    • /
    • pp.39-44
    • /
    • 2002
  • Interfacial properties and microfailure modes or electrodeposition(ED) treated carbon fiber reinforced polyetherimide(PEI) toughened epoxy composites were investigated using microdroplet test. ED was performed to improve the interfacial shear strength(IFSS). As PEI content increased, IFSS increased due to enhanced toughness and plastic deformation of PEI. In the untreated cafe, IFSS Increased with adding PEI content, and IFSS of pure PEI matrix showed the highest. On the other hand, thor ED-treated case IFSS increased with PEI content with rather low improvement rate. In the untreated case, neat epoxy resin appeared brittle microfailure mode, whereas pure PEI matrix exhibited more likely ductile microfailure mode. In the ED-treated case, neat epoxy exhibited more ductile fracture compared to the untreated case. Interfacial properties of epoxy-PEI composite can be affected efficiently by both the control of matrix toughness and ED treatment.

Nondestructive Evaluation and Microfailure Mechanisms of Single Fibers/Brittle Cement Matrix Composites using Electro-Micromechanical Technique and Acoustic Emission (Electro-Micromechanical 시험법과 Acoustic Emission을 이용한 단섬유/시멘트 복합재료의 미세파괴 메커니즘과 비파괴적 평가)

  • 박종만;이상일;김진원;윤동진
    • Composites Research
    • /
    • v.14 no.3
    • /
    • pp.18-31
    • /
    • 2001
  • Interfacial and microfailure properties of the modified steel, carbon and glass fibers/cement composites were investigated using electro-pullout test under tensile and compressive tests with acoustic emission (AE). The hand-sanded steel composite exhibited higher interfacial shear strength (IFSS) than the untreated and even neoalkoxy zirconate (Zr) treated steel fiber composites. This might be due to the enhanced mechanical interlocking, compared to possible hydrogen or covalent bonds. During curing process, the contact resistivity decreased rapidly at the initial stage and then showed a level-off. Comparing to the untreated case, the contact resistivity of either Zr-treated or hand-sanded steel fiber composites increased to the infinity at latter stage. The number of AE signals of hand-sanded steel fiber composite was much more than those of the untreated and Zr-treated cases due to many interlayer failure signals. AE waveforms for pullout and frictional signals of the hand-sanded composite are larger than those of the untreated case. For dual matrix composite (DMC), AE energy and waveform under compressive loading were much higher and larger than those under tensile loading, due to brittle but well-enduring ceramic nature against compressive stress. Vertical multicrack exhibits fur glass fiber composite under tensile test, whereas buckling failure appeared under compressive loading. Electro-micromechanical technique with AE can be used as an efficient nondestructive (NDT) method to evaluate the interfacial and microfailure mechanisms for conductive fibers/brittle and nontransparent cement composites.

  • PDF