• 제목/요약/키워드: 층간분리성장률

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항공기용 하이브리드 복합재료의 섬유배향각에 따른 피로균열전파와 층간분리 거동

  • 김태수;송삼홍;김철웅
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2004년도 춘계학술대회 논문요약집
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    • pp.76-76
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    • 2004
  • 하이브리드 복합재료 중에서 적충형태의 Al/GFRP는 단일재 알루미늄에 비해 피로특성, 비강도, 비강성 등이 매우 우수하여 Fig. 1과 같이 항공기 주익 구조에 주로 적용된다. 그러나 이러한 Al/GFRP 적층재 역시 장시간에 걸쳐 비행하중을 받게 되면 다양한 형태의 파손이 발생할 수 있다. 이 중 알루미늄층과 섬유층 사이에서 발생하는 층간분리는 Al/GFRP 적층재의 대표적인 피로파손 형태이며, 현재 이러한 파손은 다 방면으로 연구되고 있다.(중략)

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균열길이와 층간분리 폭의 관계를 이용한 하이브리드 복합재의 층간분리 거동 평가 (Evaluation of Delamination Behavior in Hybrid Composite Using the Crack Length and the Delamination Width)

  • 송삼홍;김철웅
    • 대한기계학회논문집A
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    • 제28권1호
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    • pp.55-62
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    • 2004
  • Although the previous researches evaluated the fatigue behavior of glass fiber/epoxy laminates using the traditional fracture mechanism, their researches were not sufficient to do it: the damage zone of glass fiber/epoxy laminates was occurred at the delamination zone instead of the crack-metallic damages. Thus, previous researches were not applicable to the fatigue behavior of glass fiber/epoxy laminates. The major purpose of this study was to evaluate delamination behavior using the relationship between crack length and delamination width in hybrid composite material such as Al/GFRP laminate. The details of investigation were as follows : 1) Relationship between crack length and delamination width, 2) Relationship between delamination aspect ratio and delamination area rate, 3) Variation of delamination growth rate is attendant on delamination shape factors. The test results indicated that the delamination growth rate depends on delamination width delamination aspect ratio and delamination shape factors.

층간분리 요소와 층간분리 성장의 관계 (The Relationship Between Delamination Element and Delamination Growth)

  • 송삼홍;김철웅;홍정화;김태수;황진우
    • 한국복합재료학회:학술대회논문집
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    • 한국복합재료학회 2003년도 춘계학술발표대회 논문집
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    • pp.113-116
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    • 2003
  • The investigation of delamination growth behavior in hybrid composite material such as FRMLs should be considered delamination growth rate, dA_D/da$ using the delamination shape factor, $f_S$ instead of traditional fracture mechanics parameters. The main objective of this study is to evaluate the relationship between delamination element (i. e. delamination width, b, delamination contour, c, delamination shape factor, $f_S$ and delamination growth rate, dA_D/da$) and delamination growth in FRMLs under cyclic bending moment. The delamination shape formed along the fatigue crack between aluminum layer and glass fiber/epoxy layer are measured by scanning method. The details of study are as follow : ⅰ) Relationship between crack length, a and delamination width, b. ⅱ) Variation of delamination growth rate, dA_D/da$ was attendant on delamination shape factors, $f_{S1}$, $f_{S2}$, $f_{S3}$. The test result indicated the delamination growth behavior depends in delamination element such as delamination width, b, delamination shape factors, $f_{S1}$, $f_{S2}$, $f_{S3}$.

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층간분리 형상계수($F_s$)가 FRMLs의 층간분리 성장률($dA_D/da$)에 미치는 영향 (The Effect of Delamination Shape Factor, $f_s$ on the Delamination Growth Rate, $dA_D/da$ in FRMLs)

  • 송삼홍;이원평;김광래;김철웅
    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 2003년도 춘계학술대회 논문집
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    • pp.398-404
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    • 2003
  • Most previous researches for the hybrid composite materials such as FRMLs(Al/AFRP, Al/GFRP) have evaluated the fatigue delamination behavior using the traditional fracture mechanism. However, most previous researches have not generally been firmed yet. Because delamination growth behavior in hybrid composite should be consider delamination growth rate, $dA_D$/da using the delamination shape factors, fs instead of traditional fracture mechanic parameters. The major purpose of this study was to evaluate the relationship between delamination shape factor, fs and delamination growth rate, $dA_D$ . And a propose parameter on the delamination aspect ratio, b/a. The details of the study are as follow : 1) Relationship between crack length, a and delamination width,b. 2) Relationship between delamination aspect ration, b/a and delamination area rate,($(A_D)_{N}(A_D)_{ALL}$. 3) Variation of delamination growth rate, $dA_D/da$ was attendant on delamination shape factors, $fs_1$, $fs_2$, $fs_3$. The test results indicated the delamination growth rate depends on delamination shape factors.

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항공기 주익용 하이브리드 복합재의 섬유배향각과 층간분리 성장과의 관계 (The Relationship between Fiber Stacking Angle and Delamination Growth of the Hybrid Composite Material on an Aircraft Main Wing)

  • 송삼홍;김철웅;김태수;황진우
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2003년도 춘계학술대회 논문집
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    • pp.1402-1405
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    • 2003
  • The main object of this study was evaluated by the delamination damage for fiber stacking angle. Therefore, this work need to compare the shape of delamination for a different fiber stacking angie. So this study uses a method of fatigue test which was created [0]$_2$,[+45]$_2$[90]$_2$. The extension of the delamination zone formed between aluminium alloy and glass fiber-adhesive layer were measured by an ultrasonic C-scan image. As a result, the shapes of delamination zone don't depend upon the crack propagation. We could know that the delamination zone grew interaction between stress flow of fiber layer and crack driving force. Hence, the existing study were applied to the stress transfer, fiber bridging effect, delaminantion growth rate should need to the develop useful factor because of change of fiber stacking angle.

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변형률 에너지 해방률에 기반한 Carbon/Epoxy 직교적층판의 모드 I 층간 및 층내 파괴 특성 분석 (The Characteristics for Mode I Interlaminar and Intralaminar Fractures of Cross-Ply Carbon/Epoxy Composite Laminates Based on Energy Release Rate)

  • 강민송;전민혁;김인걸;우경식
    • Composites Research
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    • 제32권1호
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    • pp.6-12
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    • 2019
  • 본 논문에서는 Cross-ply 탄소섬유/에폭시 복합재 적층판의 모드 I 층간분리 특성을 분석하였다. 이를 위하여 Cross-ply 시편에 대한 Double-Cantilever Beam(DCB) 시험을 수행하였다. Cross-ply DCB 시편의 경우 층간 및 층내 파괴를 포함한 복합적인 균열 성장과 기하학적 대변형에 의한 비선형성을 수반하였다. 따라서 변형률 에너지 해방률과 유한요소해석을 기반으로 비선형성을 수반한 DCB 시험에서도 적용되는 모드 I 층간 파괴인성 평가방법을 제안하고 기존의 선형이론으로 구한 결과와 비교 분석하였다. 본 연구에서 제안한 방법으로 Cross-ply DCB 시편의 모드 I 층간 파괴인성과 모드 I 층내 파괴인성을 분류하였고 모드 I 층내 파괴인성이 더욱 낮음을 확인하였다.

인공발(Prosthetic Foot) 스프링용 유리섬유강화 적층재의 적층배향에 따른 층간분리거동 해석 (Analysis of Delamination Behavior on the Stacking Sequence of Prosthetic Foot Keel in Glass fiber Reinforced Laminates)

  • 송삼홍;김철웅
    • 대한기계학회논문집A
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    • 제27권4호
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    • pp.623-631
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    • 2003
  • It is considered that the application of advanced composite materials to the prostheses for the disables is important to improve their bio-mechanical performance. Particularly, energy storing foot prosthesis is mostly important to restore gait ability of the disables with low-extremity amputation since it could provide propulsion at terminal stance enhancing the disables ability to walk long distance even run and jump. Therefore, the energy storing spring of Prosthetic foot keel under cyclic bending moment use mainly of high strength glass fiber reinforced plastic. The main objective of this study was to evaluate the stacking sequence effect using the delamination growth rate(dA$_{D}$/dN) of energy storing spring in glass fiber reinforced plastic under cyclic bending moment. The test results indicated that the shape of delamination zone depends on stacking sequence in GFRP laminates. Delamination area(A$_{D}$) turns out that variable types with the contour increased non-linearly toward the damage zones.nes.

층간분리성장률(dAD/da)과 섬유가교효과인자(FBE)를 이용한 Al/GFRP 적층재의 피로거동 해석 (The Analysis of Fatigue Behavior Using the Delamination Growth Rate(dAD/da) and Fiber Bridging Effect Factor(FBE) in Al/GERP Laminates)

  • 송삼홍;김철웅
    • 대한기계학회논문집A
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    • 제27권2호
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    • pp.317-326
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    • 2003
  • The influence of cyclic bending moment on the delamination and the fatigue crack propagation behavior in Al/GFRP laminate such as the wing section was investigated. The main objective of this study was to evaluate the relationship between crack profile and delamination behavior. And a propose parameter on the delamination growth rate(d $A_{D}$/da) of Al/GFRP laminates with a saw-cut using relationship between delamination area( $A_{D}$) and cycles(N), crack length(a), stress intensity factor range($\Delta$K). Also, the fiber bridging effect factor( $F_{BE}$ ) was propose that the fiber bridging modification factor($\beta$$_{fb}$ ) to evaluate using the delamination growth rate(d $A_{D}$/da). The shape and size of the delamination zone formed along the fatigue crack between aluminum alloy sheet. Class fiber-adhesive layer were measured by an ultrasonic C-scan image. The shape of delamination zone turns out to be semi-elliptic with the contour decreased non-linearly toward the crack tip. It represents that relationship between crack length and delamination growth rate(d $A_{D}$/da) were interdependent by reciprocal action, therefore it's applicable present a model for the delamination growth rate(dA/sib D//da) in Al/GFRP laminates.minates.s.

균열이 발생하지 않는 섬유강화 복합재료의 층간분리 평가법 (Evaluation of Delamination for Fiber Reinforced Composite Material without Crack)

  • 송삼홍;김철웅;황진우
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2003년도 춘계학술대회 논문집
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    • pp.1349-1353
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    • 2003
  • Previous researches for fiber reinforced composite material(FRCM) have been evaluated the fatigue delamination behavior using the traditional fracture mechanics parameters. Therefore. previous researches for FRCM have not generally been firmed yet. Because delamination growth behavior in FRCM should be consider relationship between delamination area, A$\sub$D/ and crack length, a instead of traditional fracture mechanics parameters. Especially, in case of delamination behavior for FRCM without crack should be considering equivalent crack, i.e., pseudo crack, a$\sub$p/, using the fracture behavior of FRCM with crack. The major purpose of this study was to evaluate the delamination for FRCM without crack. The details of the studies are as follow : 1) Relationship between crack growth rate, da/dN and stress intensity factor, ΔK in FRCM containing a saw-cut and circular hole with crack. 2) Propose of PSEUDO CRACK MODEL for the delamination in FRCM without crack. 3) Analysis of crack propagation energy, E$\sub$crack/ using a total energy, E$\sub$total/ and delamination growth energy, E$\sub$del/.

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반복-굽힘 모멘트가 A15052/AFRP 적층재의 층간분리 영역과 피로균열진전에 미치는 영향 (The Influence of Cyclic-bending Moment on the Delamination Zone and the Fatigue Crack Propagation in A15052/AFRP Laminates)

  • 송삼홍;김철웅
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2000년도 추계학술대회논문집A
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    • pp.231-237
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    • 2000
  • A15052/AFRP laminates were developed principally to obtain a material with good fatigue strength, in which possible cracks would grow very slowly. Weight savings of more than 30% should be attainable in practice. Also, the crack bridging fibers could still was carry a significant part of the load over the crack, thus the COD and stress intensity factor was reduced at the crack tip. A15052/ AFRP laminates consists of three thin sheets of 5052-H34 aluminum alloy and two layers of [0] unidirectional aramid fiber prepreg. The cyclic-bending moment test was investigated based on applying the five kinds of bending moments. The size of the delamination zone produced between 5052-H34 aluminum alloy sheets and fiber-adhesive layers was measured from ultrasonic C-scan pictures taken around the fatigue crack. In addition, the relationship between the cyclic-bending moment and the delamination zone size was studied and the effect of fiber bridging mechanism was also considered.

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