Original Article
  • Study on Microfailure Mechanism of Single-Fiber Composites using Tensile/Compressive Broutman Fragmentation Techniques and Acoustic Emission
  • Joung-Man Park, Jin-Won Kim, Dong-Jin Yoon
  • 인장/압축 Broutman Fragmentation시험법과 음향방출을 이용한 단섬유 복합재료의 미세파괴 메커니즘의 연구
  • 박종만(경상대학교 응용화학공학부/고분자공학전공, 항공기부품기술연구센타), 김진원(경상대학교 대학원 고분자공학과), 윤동진(한국표준과학연구원 방재기술센타 비파괴평가그룹)
Abstract
Interfacial and microfailure properties of carbon fiber/epoxy matrix composites were evaluated using both tensile fragmentation and compressive Broutman tests with an aid of acoustic emission (AE) monitoring. A polymeric maleic anhydride coupling agent and a monomeric amino-silane coupling agent were used via the electrodeposition (ED) and the dipping applications, respectively. Both coupling agents exhibited significant improvements in interfacial shear strength (IFSS) compared to the untreated case under tensile and compressive tests. The typical microfailure modes including fiber break of cone-shape, matrix cracking, and partial interlayer failure were observed during tensile test, whereas the diagonal slippage in fiber ends was observed under compressive test. For both loading types, fiber breaks occurred around just before and after yielding point. In both the untreated and treated cases AE amplitudes were separately distributed for the tensile testing, whereas they were closely distributed for the compressive tests. It is because of the difference in failure energies of carbon fiber between tensile and compressive loading. The maximum AE voltage for the waveform of carbon or basalt fiber breakages under tensile tests exhibited much larger than those under compressive tests, which can provide the difference in the failure energy of the individual failure processes.

Interfacial and microfailure properties of carbon fiber/epoxy matrix composites were evaluated using both tensile fragmentation and compressive Broutman tests with an aid of acoustic emission (AE) monitoring. A polymeric maleic anhydride coupling agent and a monomeric amino-silane coupling agent were used via the electrodeposition (ED) and the dipping applications, respectively. Both coupling agents exhibited significant improvements in interfacial shear strength (IFSS) compared to the untreated case under tensile and compressive tests. The typical microfailure modes including fiber break of cone-shape, matrix cracking, and partial interlayer failure were observed during tensile test, whereas the diagonal slippage in fiber ends was observed under compressive test. For both loading types, fiber breaks occurred around just before and after yielding point. In both the untreated and treated cases AE amplitudes were separately distributed for the tensile testing, whereas they were closely distributed for the compressive tests. It is because of the difference in failure energies of carbon fiber between tensile and compressive loading. The maximum AE voltage for the waveform of carbon or basalt fiber breakages under tensile tests exhibited much larger than those under compressive tests, which can provide the difference in the failure energy of the individual failure processes.

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This Article

  • 2000; 13(4): 54-66

    Published on Aug 31, 2000

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