• Composites Research
• /
• v.20 no.5
• /
• pp.1-6
• /
• 2007

This study was performed to make a comparison on low-velocity impact behavior between graphite/epoxy composite laminate and steel plate. In order to validate the proposed scheme fur the impact behavior of the plate, the Karas's impact model was used. The impact models for this comparative study are the graphite/epoxy composite plate having $[0/90/45/-45/-45/45/90/0]_{8S}$ laminate sequence and the steel plate with a steel ball impactor. The low-velocity impact behaviors for two types of plates were comparatively investigated and performed by considering different impactor velocities and weights respectively. In this investigation, it was found that the composite laminate has impact energy absorption effect due to more flexible behavior than the steel plate, and also it has better characteristics on impact damage and weight.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.15 no.3
• /
• pp.757-770
• /
• 1991

본 연구에서는 조속충격을 받는 복합적층판의 거동에 대해 횡전단변형과 대처 짐효과를 동시에 고려하여 선형해석한 결과와의 차이를 비교, 검토하여 저속충격무제 의 해석에 있어서 비선형해석의 중요성을 보이는데 있다.그리고 충격체의 질량과 속도가 충격하중과 판의 거동, 그리고 동적 변형도등에 미치는 영향을 파악하여 복합 적층판의 외부 물체에 의한 저속충격문제를 이해 하고자 한다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2007.11a
• /
• pp.1446-1449
• /
• 2007

인정바닥구조는 신청에서부터 인정서 발급까지 기본적으로 2개월 이상이 소요되며, 신청 제품이 많을수록 그 기간은 길어지게 된다. 본 논문은 이와 같은 완충재의 성능을 확인하기 위해 소요되는 기간과 비용을 획기적으로 단축할 수 있는 간편한 방법을 제시하기 위한 것이다. 완충재 설치 이후 습식으로 시공되는 경량기포콘크리트와 모르터를 사전에 일정 크기로 제작(축소모형 시험판)한 후 골조가 완성된 현장에서 바닥충격음을 측정하는 방법이다. 완충재 2개 제품에 대하여 축소모형 시험판을 이용하여 측정한 결과와 전체 세대를 시공한 후 측정한 결과를 비교한 결과 경량충격음은 축소모형 시험판이 훨씬 낮은 결과를 나타냈지만 중량충격음은 비슷한 결과를 나타냈다. 이로써 축소모형 시험판을 이용하여 바닥충격음을 측정하는 것은 경량충격음을 저감하기 위한 재료 선정 및 제품 시스템 구성 등에 활용될 수 있을 것이며, 현장에서 중량충격음 차단성능을 신속하게 검증할 수 있는 방법으로 활용할 수 있을 것으로 기대된다.

• Composites Research
• /
• v.22 no.6
• /
• pp.18-22
• /
• 2009

In this paper, we examined impact force and impact behavior through low velocity impact tests of composite laminates. And through c-scan as nondestructive inspection, explored the damaged area being difficult to examine with the visual inspection. Through CAI tests, we also measured the compression strength of composite laminates subjected to low velocity impact. To examine the characteristics of impact behavior measured from low velocity impact test, nondestructive inspection, and CAI test, the simulated data are generated from the test data using Monte-Carlo simulation, then represented it by probability distribution. The testing results using visible stochastic distribution were examined and compared.

• Journal of the Society of Naval Architects of Korea
• /
• v.36 no.2
• /
• pp.77-93
• /
• 1999

The twin aims of the paper are to investigate the collapse strength characteristics of ship plating subject to impact pressure loads and to develop a simple structural design formula considering impact load effects. The general purpose nonlinear finite element program STARDYNE together with existing experimental results is used to investigate the collapse behavior of plating under impact pressure loads. The rigid plastic theory taking into account large deflection effects is applied to the development of the design formulation. In the theoretical method, the collapse strength formulation for plating subject to hydrostatic pressure is first derived using the rigid plastic theory. By including the strain rate erects in the formulation it can be applied to impact pressure problems. As illustrative examples, the collapse behavior of steel unstiffened plates and aluminum alloy stiffened panels subject to impact pressure loads is analyzed.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2010.04a
• /
• pp.465-475
• /
• 2010

구조물의 손상을 평가하기 위한 적용되는 태핑 테스트를 효과적이고, 정확하게 사용하기 위하여 적층판의 충격 시 발생하는 현상을 수치적인 방법을 이용하여 해석하였다. 구조물의 진동에 의해 방사되는 음은 구조물의 거동과 직접적으로 연관되므로 충격응답해석이 수행되어야 한다. 본 논문에서는 층간분리가 존재하는 적층판의 해석을 위하여 층간분리 모델을 사용하였으며, 해머 형상의 충격체를 모사할 수 있는 효과적인 스프링-질량모델을 제시하였다. 또한 태핑 테스트 시 방사되는 음압을 Rayleigh 적분식을 이용하여 해석하였다. 예측된 음압이력과 시험결과와 비교하였으며, 음압이력과 충격하중이력에 손상이 주는 영향을 검토하였다. 방사되는 음압과 충격하중이력은 적층판에 존재하는 손상에 영향을 받는 것을 보였다. 결과적으로 제안된 음을 이용한 태핑실험은 복합재에 존재하는 손상을 검출하는데 신뢰성 있는 방법임을 알 수 있었다.

• Composites Research
• /
• v.26 no.6
• /
• pp.349-354
• /
• 2013

In this paper, we conducted high velocity impact test for Carbon/Epoxy composite laminates and proposed advanced method for predicting the absorbed energy of composite laminates. During high-velocity impact test, we discovered loss of projectile mass macroscopically using high speed camera, thus we calculated the absorbed energy of composite laminates by taking loss of projectile mass into account. We proposed a model for predicting the absorbed energy of composite laminates subjected to high-velocity impact, the absorbed energy was classified into static energy and dynamic energy. The static energy was calculated by the quasi-static perforation equation that is related to the fiber breakage and static elastic energy. The dynamic energy can be divided by the kinetic energy of deformed specimen and fragment mass. Finally, the predicted absorbed energy considering loss of projectile mass was compared with experimental results.

• Composites Research
• /
• v.18 no.3
• /
• pp.7-13
• /
• 2005

This paper presents a study on the low velocity impact response of the woven fabric laminates for the hybrid composite bodyshell of a tilting railway vehicle. In this study, the low velocity impact tests for the three laminates with size of $100mm\times100mm$ were conducted at three impact energy levels of 2.4J, 2.7J and 4.2J. Based on the tests, the impact force, the absorbed energy and the damaged area were investigated according to the different energy levels and the stacking sequences. The damage area was evaluated by the visual inspection and the C-scan device. The test results show that the absorbed energy of [fill]8 laminate is highest whereas (fill2/warp2)s is lowest. The [fill]8 laminate has the largest damage area because of the highest impact energy absorption.

• Composites Research
• /
• v.16 no.1
• /
• pp.50-57
• /
• 2003

Usually many researchers have used the modified Hertzian contact law or experimental static indentation law to analyze impact response of composite laminates subjected to the low-velocity impact. In this study, physical meaning of the method using the laws was investigated and the difference between the analytical results obtained using the laws was also investigated. Furthermore parametric study on contact constant and exponent in the contact law was performed. Finally it was shown that a linearized contact law can be well applied to low-velocity impact response analysis of composite laminates. If this concept is used, commercial finite element software can be used to solve impact problem without making any auxiliary code.

• Proceedings of the KSME Conference
• /
• 2005.11a
• /
• pp.79.2-79.2
• /
• 2005