• 제목/요약/키워드: 잔류피로굽힘강도

검색결과 3건 처리시간 0.015초

충격하중을 받은 CFRP 적층판의 손상거동과 잔류굽힘피로강도 (Damage Behavior and Residual Bending Fatigue Strength of CFRP Composite Laminates Subjected to Impact Loading)

  • 임광희;양인영
    • 대한기계학회논문집A
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    • 제20권6호
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    • pp.1836-1842
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    • 1996
  • In this paper, static and fatigue bending strengths of CFRP(carbon fiber reinforced plastic laminates having impact damage(FOD) are evaluated. Composite laminates used for this experiment are CF/EPOXY and CF/PEEK orthotropy laminated plates, which have two-interfaces[${0^0}_4{90^0}_4}$]$_sym$. A steel ball launched by the air gun colides against CFRP laminates to generate impact damages. The damage growth during bending fatigue test is observed by the scanning acoustic microscope(SAM). When the impacted side is compressed, the residual fatigue bending strength of CF/PEEK specimen P is greater that that of CF/EPOXY SPECIMEN B. On the other hand, when the impacted side is in tension, the residual fatigue bending strength of CF/PEEK speicemen P is smaller than that of CF/EPOXY specimen B. In the case of impacted-side compression, fracture is proposed from the transverse crack generated near impact point. On the other hand, fracture is developed toward the impact point from the edge of interface-b delamination in the case of impacted-side tension.

고온.고습하에서 직교이방성 CFRP 복합적층판이 잔류피로 굽힘강도에 미치는 영향에 관한 연구 (A Study on Effects to Residual Fatigue Bending Strength or Orthotropy CFRP Composite Laminates under High Temperature and Moisture)

  • 임광희;양인영
    • 한국자동차공학회논문집
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    • 제8권6호
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    • pp.247-258
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    • 2000
  • It is thought that impact damages and hygrothermals can affect to CFRP (Carbon-fiber reinforced plastic) composite laminated due to the sensitivity on the composite laminated Therefore, this paper focuses on the fracture mechanisms experimentally based on a scanning acoustic microscope (SAM) when subjected to impact damages, i.e., foreign object damages(FOD), and also the influence of impact damages and hygrothermals on residual fatigue bending strength of CFRP laminates. Composite laminates used in the experiment are CF/EPOXY orthotropy laminated plates, which constist of two-interfaces [04/904]s. A steel ball launched by an air gun collides against CFRP laminates to generate impact damages. Bending fatigue tests are periodically interrupted for a nondestructive evaluation (NDE) measurement of the progrossive damages to built the fracture mechanism by impact damages, and three-point fatigue bending tests are carried out to investigate the influence of hygrothermals on the effect on the residual bending fatigue strength of CFRP laminates.

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CF/Epoxy적층판의 충격손상거동에 관한 연구 (A Study on Impact Damage Behavior of CF/Epoxy Composite Laminates)

  • 임광희;심재기;양인영
    • 대한기계학회논문집A
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    • 제26권5호
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    • pp.835-842
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    • 2002
  • In this paper, static and fatigue bending strengths and failure mechanisms of CFRP (carbon fiber reinforced plastics) laminates having impact damages have been evaluated. Composite laminates used for this experiment are CF/EPOXY orthotropy laminated plates, which have two-interfaces $[0^0_ 4/90^0_4]_{ sym}$. A steel ball launched by the air gun collides against CFRP laminates to generate impact damages. The damage growth during bending fatigue test is observed by the scanning acoustic microscope (SAM) and also, the fracture surfaces were observed by using the SEM (scanning electron microscope). In the case of impacted-side compression, fracture is propagated from the transverse crack generated near impact point. On the other hand, fracture is developed toward the impact point from the edge of interface-B delamination in the case of impacted-side tension. Eventually, failure mechanisms have been confirmed based on the observed delamination areas and fracture surfaces.