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High-Velocity Impact Damage Behavior of Carbon/Epoxy Composite Laminates
Kim, Young A.,Woo, Kyeongsik,Cho, Hyunjun,Kim, In-Gul,Kim, Jong-Heon The Korean Society for Aeronautical and Space Scie 2015 International Journal of Aeronautical and Space Sc Vol.16 No.2
In this paper, the impact damage behavior of USN-150B carbon/epoxy composite laminates subjected to high velocity impact was studied experimentally and numerically. Square composite laminates stacked with $[45/0/-45/90]_{ns}$ quasi-symmetric and $[0/90]_{ns}$ cross-ply stacking sequences and a conical shape projectile with steel core, copper skin and lead filler were considered. First high-velocity impact tests were conducted under various test conditions. Three tests were repeated under the same impact condition. Projectile velocity before and after penetration were measured by infrared ray sensors and magnetic sensors. High-speed camera shots and C-Scan images were also taken to measure the projectile velocities and to obtain the information on the damage shapes of the projectile and the laminate specimens. Next, the numerical simulation was performed using explicit finite element code LS-DYNA. Both the projectile and the composite laminate were modeled using three-dimensional solid elements. Residual velocity history of the impact projectile and the failure shape and extents of the laminates were predicted and systematically examined. The results of this study can provide the understanding on the penetration process of laminated composites during ballistic impact, as well as the damage amount and modes. These were thought to be utilized to predict the decrease of mechanical properties and also to help mitigate impact damage of composite structures.
Numerical Simulation of High Velocity Impact of Circular Composite Laminates
Kyeongsik Woo,In-Gul Kim,Jong Heon Kim,Douglas S. Cairns 한국항공우주학회 2017 International Journal of Aeronautical and Space Sc Vol.18 No.2
In this study, the high-velocity impact penetration behavior of [45/0/-45/90]㎱ carbon/epoxy composite laminates was studied. The considered configuration includes a spherical steel ball impacting clamped circular laminates with various thicknesses and diameters. First, the impact experiment was performed to measure residual velocity and extent of damage. Next, the impact experiment was numerically simulated through finite element analysis using LS-dyna. Three-dimensional solid elements were used to model each ply of the laminates discretely, and progressive material failure was modeled using MAT162. The result indicated that the finite element simulation yielded residual velocities and damage modes well-matched with those obtained from the experiment. It was found that fiber damage was localized near the impactor penetration path, while matrix and delamination damage were much more spread out with the damage mode showing a dependency on the orientation angles and ply locations. The ballistic-limit velocities obtained by fitting the residual velocities increased almost linearly versus the laminate diameter, but the amount of increase was small, showing that the impact energy was absorbed mostly by the localized impact damage and that the influence of the laminate size was not significant at high-velocity impact.
물리적 공간과 가상공간의 동기화를 위한 웹 기반 가상 제조 공정 트윈 모델 설계 및 구현
김경식(Kyeongsik Kim),임병묵(Byungmuk Im),최성수(Sungsu Choi),지수영(Suyoung Chi),류관희(Kwan-Hee Yoo) 한국정보기술학회 2016 한국정보기술학회논문지 Vol.14 No.2
As manufacture industry has transformed into Industry 4.0, smart factory, which aims at predictive manufacturing, attracts attention in manufacture industry. In the smart factory, CPS(Cyber Physical System) supports interaction between human and physical factors of production on cyberspace. Moreover CPS enables users to monitor and cope with the situation, and also offers predictive information from real-time data collection, which helps users figure out invisible problem and prevent that. That may lead to flexible operation and problem solving in increasingly high complexity of manufacture industry. In this paper, the interface of ‘Twin Model’, which synchronizes physical factors of production in ‘Cyber Space’ is designed and realized. That interface supports intercommunication between human and physical objects of production.
Numerical Simulation of High Velocity Impact of Circular Composite Laminates
Woo, Kyeongsik,Kim, In-Gul,Kim, Jong Heon,Cairns, Douglas S. The Korean Society for Aeronautical and Space Scie 2017 International Journal of Aeronautical and Space Sc Vol.18 No.2
In this study, the high-velocity impact penetration behavior of $[45/0/-45/90]_{ns}$ carbon/epoxy composite laminates was studied. The considered configuration includes a spherical steel ball impacting clamped circular laminates with various thicknesses and diameters. First, the impact experiment was performed to measure residual velocity and extent of damage. Next, the impact experiment was numerically simulated through finite element analysis using LS-dyna. Three-dimensional solid elements were used to model each ply of the laminates discretely, and progressive material failure was modeled using MAT162. The result indicated that the finite element simulation yielded residual velocities and damage modes well-matched with those obtained from the experiment. It was found that fiber damage was localized near the impactor penetration path, while matrix and delamination damage were much more spread out with the damage mode showing a dependency on the orientation angles and ply locations. The ballistic-limit velocities obtained by fitting the residual velocities increased almost linearly versus the laminate diameter, but the amount of increase was small, showing that the impact energy was absorbed mostly by the localized impact damage and that the influence of the laminate size was not significant at high-velocity impact.
High-Velocity Impact Damage Behavior of Carbon/Epoxy Composite Laminates
Young A. Kim,Kyeongsik Woo,Hyunjun Cho,In-Gul Kim,Jong-Heon Kim 한국항공우주학회 2015 International Journal of Aeronautical and Space Sc Vol.16 No.2
In this paper, the impact damage behavior of USN-150B carbon/epoxy composite laminates subjected to high velocity impact was studied experimentally and numerically. Square composite laminates stacked with [45/0/-45/90]ns quasi-symmetric and [0/90]ns cross-ply stacking sequences and a conical shape projectile with steel core, copper skin and lead filler were considered. First high-velocity impact tests were conducted under various test conditions. Three tests were repeated under the same impact condition. Projectile velocity before and after penetration were measured by infrared ray sensors and magnetic sensors. High-speed camera shots and C-Scan images were also taken to measure the projectile velocities and to obtain the information on the damage shapes of the projectile and the laminate specimens. Next, the numerical simulation was performed using explicit finite element code LS-DYNA. Both the projectile and the composite laminate were modeled using three-dimensional solid elements. Residual velocity history of the impact projectile and the failure shape and extents of the laminates were predicted and systematically examined. The results of this study can provide the understanding on the penetration process of laminated composites during ballistic impact, as well as the damage amount and modes. These were thought to be utilized to predict the decrease of mechanical properties and also to help mitigate impact damage of composite structures.
PVDF 센서를 이용한 수압램 하중을 받는 복합재 T-Joint의 동적 변형률 측정
고은수 ( Eun-su Go ),김동건 ( Dong-geon Kim ),김인걸 ( In-gul Kim ),우경식 ( Kyeongsik Woo ),김종헌 ( Jong-heon Kim ) 한국복합재료학회 2018 Composites research Vol.31 No.5
수압램 현상은 전투용 항공기의 주요 전투 손상 중 하나이며, 항공기 기체 생존성 평가에 중요한 영향을 미친다. 수압램 효과는 유체-구조물간의 상호관계를 통하여 나타나며, 구조물의 동적 변형률을 측정하여 파손 거동 및 파손 여부를 확인할 수 있다. 본 논문에서는 수압램 현상을 모사할 수 있는 수압램 시험 장치를 이용하여 수압램에 의한 복합재 T-Joint의 파손 시험을 수행하였다. 또한 계측기기의 입력 정전용량과 시간 상수 확인을 위해 PVDF 센서 보정 시험을 수행하였다. 복합재 T-Joint에 스트레인 게이지와 전하증폭기를 사용하지 않은 PVDF 센서를 부착하여 수압램 현상에 의한 복합재 T-Joint의 동적 변형률을 측정하였다. PVDF 센서와 스트레인 게이지의 동적 변형률을 이용하여 복합재 T-Joint의 파손 거동 및 파손 여부를 확인하였다. The hydrodynamic ram (HRAM) phenomenon is one of the main types of ballistic battle damages of a military aircraft and has great importance to airframe survivability design. The HRAM effect occurs due to the interaction between the fluid and structure, and damage can be investigated by measuring the pressure of the fluid and the dynamic strains on the structure. In this paper, HRAM test of a composite T-Joint was performed using a ram simulator which can generate HRAM pressure. In addition, calibration tests of PVDF sensor were performed to determine the circuit capacitance and time constant of the measurement system. The failure behavior of the composite T-Joint due to HRAM pressure was examined using the strain gauges and a PVDF sensor which were attached to the surface of the composite T-Joint.