• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2001년도 추계학술발표대회 논문집
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• pp.179-182
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• 2001

Impacter tester was build of to evaluate the characterization of non-flamable Glass/phenol laminate plates under the low velocity impact. The damage of composite laminates are matrix cracking, delamination, and fiber breakage for impact energy. In this study, this is to find impact properties of Glass/phenol in used in a forehead part of lighting subway. To determine impact damage characteristics which is made in a laminate, use the UT C-scan after- macrography. And then evaluated the reduction of strength in a rate of impact energy with CAI(Compression After Impact) test

• 폴리머
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• 제26권2호
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• pp.270-278
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• 2002

저밀도 2-D 탄소/탄소 복합재료의 저속 충격에 의한 파괴 거동과 첨가제에 따른 충격 에너지 흡수 경향을 연구하였다. 저속 충격시험은 mini tower 낙추 충격 시험기를 이용하였으며, 흑연, 카본블랙, 분쇄탄소섬유를 첨가제로 선택하였다. 흑연의 첨가는 최대하중값을 증가시켰으며, 전체적인 관통이 일어나기까지 응력을 오랫동안 유지시키는 효과를 나타내었다. 특히 9 vol%의 함량에서 흑연이 첨가되지 않은 씨편보다 약 42%의 충격 흡수 개선을 보였다. 약 0.4 J의 낮은 충격에너지에 의한 충격 회수에 따른 실험에서 첨가제가 첨가되지 않은 시편의 경우, 충격에너지는 층간분리에 의해 소모되고, 흑연의 함량이 증가함에 따라 파괴 경향은 시편의 관통으로 변화함을 관찰할 수 있었다.

• Steel and Composite Structures
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• 제17권2호
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• pp.199-213
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• 2014

The damage characters of scarf repaired composite laminates subjected to low-velocity impact with various energy levels at different locations are studied experimentally. The results are compared with those of the original laminates which have no initial damage and don't need repair. The impact load-time history of the specimens, the velocity-time curves of the impactor, the post impact compressive strength of the specimens and the C-scan photographs of the damaged regions are obtained. The delamination threshold load and damage character of the specimen section at impact point are also studied. The results have shown that the impact response of a repaired composite laminate is sensitive to the location of the impact. The impact load and the delamination threshold load have shown different characters for specimens with different impact locations. The debonding characters of the adhesive and compressive strength after impact of the specimens are also influenced by impact locations.

• 한국해양공학회지
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• 제16권6호
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• pp.55-59
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• 2002

Delamination means that cracking occurs on the interface layer between composite laminates. In this paper, to predict the delamination growth in composite laminates subjected to low-velocity impact, the unit load method was introduced, and an eighteen-node 3-D finite element analysis, based on assumed strain mixed formulation, was conducted. Strain energy release rate, necessary to determine the delamination growth, was calculated by using the virtual crack closure technique. The unit load method saves the computation time more than the re-meshing method. The virtual crack closure technique enables the strain energy release rate to be easily calculated, because information of the singular stress field near the crack tip is not required. Hence, the delamination growth in composite laminates that are subjected to low-velocity impact can be efficiently predicted using the above-mentioned methods.

• 한국안전학회지
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• 제17권1호
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• pp.6-10
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• 2002

This paper presents the impact behavior and damage of laminated composite plates subjected to low-velocity impact. For this purpose, a pendulum impact test for impact behavior and C-scan for impact damage are done. Test materials are carbon/epoxy laminated composite plates and stacking sequences $[0/90_4\;[0/45_2/-45]_s,\;[0/45/-45/90]_s$ and [0/26/51/77/-77/-51/-26/0].

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.144-150
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• 2007

In this paper, the low velocity response of four different sandwich panels with metal and laminate composite facesheets has been investigated by conducting drop-weight impact tests using an instrumented falling-weight impact tower. Square samples of 100mm sides were subjected low-velocity impact loading using an instrumented testing machine at six energy levels. Impact parameters like maximum force, time to maximum force, deflection at maximum force and absorbed energy were evaluated and compared for four different types of sandwich panels. The impact test results show that sandwich panel with composite laminate facesheet could not observe damage mode of a permanent visible indentation after impact and has a good impact damage resistance in comparison with sandwich panel with metal aluminum facesheet.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1994년도 추계학술대회 논문집
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• pp.969-974
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• 1994

The dynamic behavior of graphite/epoxy laminated composite shell structure due to low-velocity impact is investigated using the finite element method. In this analysis, the Newmark's constant-acceleration time integration algorithm is used. The impact response such as contact force, central deflection and dynamic strain history form shell structure analysis are compared with those form the plate non-linear analysis. The effects of curvature, impact velocity and mass of impactor on the composite shell are discussed.

• 한국항공우주학회지
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• 제49권10호
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• pp.813-820
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• 2021

본 연구에서는 고체추진제의 동적 응력-변형률 특성을 고찰하기 위하여 저속충격시험을 수행하였다. 저속충격시험 시 충격체(Impactor)의 하중, 변위를 측정하여 고체추진제의 동적 거동을 확인하였다. 3점 굽힘 형태의 저속충격시험을 수행하였고, 이때 발생하는 국소변위와 길이가 짧고 두께가 두꺼운 고체추진제 시편의 전단 변위를 보상하여 순수 굽힘변위를 계산하였다. 보상된 변위와 측정된 하중을 사용하여 응력과 변형률을 계산하였고 응력-변형률 곡선으로부터 고체추진제의 동적 물성을 획득하여 이를 정적 굽힘 물성과 비교하였다. 운용 환경에 따른 온도별 고체추진제의 동적 물성을 획득하기 위해 상온, 고온, 저온에서 실험을 수행하고 결과를 비교분석하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 춘계학술대회 논문집
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• pp.987-988
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• 2012

• International Journal of Precision Engineering and Manufacturing
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• 제6권1호
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• pp.36-41
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• 2005