• Title, Summary, Keyword: 낙추시험

Search Result 13, Processing Time 0.041 seconds

Characteristics of Falling Weight Impact Responses due to Stacking Sequences of CF/Epoxy Composite Plates (CF/Epoxy 복합평판의 적층구성에 따른 낙추충격특성에 관한 연구)

  • 박노식;임광희;김기형;양인영
    • Composites Research
    • /
    • v.13 no.6
    • /
    • pp.30-38
    • /
    • 2000
  • In this paper, a system of falling weight impact tester was built up to evaluate the impact energy absorbing characteristics and impact strength of CFRP laminate plates in consideration of stress wave propagation theory. Delamination area of impacted specimens for the different ply orientation was measured with ultrasonic C-scanner to find correlation between impact energy and delamination area. Absorbed energy of quasi-isotropic specimen having four interfaces was higher than that of orthotropic laminates with two interfaces. The more interfaces, the more absorbed energy. Hybrid specimen containing GFRP layer was higher than that of normal specimens.

  • PDF

A Study on the Influence of Stacking Sequences using CFRP Laminate Plates by Falling Weight Impact (탄소섬유복합평판에 낙추충격을 가할 때 적층구성에 미치는 영향에 관한 연구)

  • 임광희;박노식;양인영
    • Proceedings of the Korean Society For Composite Materials Conference
    • /
    • /
    • pp.106-109
    • /
    • 2000
  • Impact tester was build up to evaluate the characterization of CFRP laminate plates under the low velocity impact. The tests were conducted on several laminates of different ply orientation A system was budded for the impact strength of CFRP laminates in consideration of stress wave propagation theory using drop-weight impact tester as one of impact test. Results indicate that absorbed energy of quasi-isotropic specimen having four interfaces is higher than that of orthotropic laminates with two interfaces. Also the damage area was measured with ultrasonic C-scanner on some samples. In the specimens the relationship was linear between damaged area and absorbed energy to some degree. Absorbed energy in the specimen that ply number, interface number and fiber stacking sequences is same but having hybrid is higher than that of orthotropic laminates without hybrid.

  • PDF

Fracture Mechanism and Characterization of Falling Weight Impact in CF/Epoxy Composite Plates Under Law-Velocity Impact (저속충격 하에서 CFRP 복합적층판의 낙추 충격특성과 파괴기구)

  • 임광희;박노식;김영남;김선규;심재기;양인영
    • Composites Research
    • /
    • v.17 no.4
    • /
    • pp.53-60
    • /
    • 2004
  • This paper describes a method for a falling weight impact test to estimate the impact energy absorbing characteristics and impact strength of CFRP laminate plates based on considerations of stress wave propagation theory. The absorbed energy of T300 orthotropic composites is higher than that of quasi-isotropic specimen over impact energy 6.8J, but in case of using T700 fiber, much difference does not show. Also, absorbed energy of T300 orthotropic composites, which are composed of the same stacking number and orientation became more than that of T700 fiber specimen; however there was no big difference in case of quasi-isotropic specimens. The delamination areas of the impacted specimen were measured with the ultrasonic C-scanner to find correlation between impact energy and delamination area. The fracture surfaces were observed by using the SEM (scanning electron microscope) through a low-velocity impact test in order to confirm the fracture mechanism.

Characteristic Analysis of Falling Weight Impact Response in CF/Epoxy Composite Plates Using Frequency Responses (주파수 응답을 이용한 CF/Epoxy 복합적층판의 낙추충격 특성평가)

  • 임광희;박노식;김영남;김선규;양인영
    • Composites Research
    • /
    • v.16 no.2
    • /
    • pp.9-17
    • /
    • 2003
  • We have implemented a system of falling weight impact tester in order to evaluate the impact energy absorbing characteristics and impact strength of CFRP laminate plates. The absorbed energy of T-300 orthotropic composites is higher than that of quasi-isotropic specimen over impact energy 7J, but in case of using T700 fiber, much difference does not show. Also, absorbed energy of T-300 orthotropic composites, which are composed of the same stacking number and orientation became more than that of T700 fiber specimen however there was no big difference in case of quasi-isotropic specimens. Delamination area of impacted specimens was measured with ultrasonic C-scanner to find correlation between impact energy and delamination area. Delamination area and frequency responses were evaluated between impacted and unimpacted specimens. There is a strong correlation between frequency responses and impact-induced delamination. The presence and scale of damages have been investigated based on the variations of frequency responses.

Impact Behavior of Fiber/Metal Laminates (FMLs) under Low Velocity (섬유/금속 적층판의 저속 충격 거동)

  • Shi, Yu;Kim, Seung-Hyun;Kim, Byung-Sun;Song, Jong-Il
    • Composites Research
    • /
    • v.23 no.1
    • /
    • pp.8-16
    • /
    • 2010
  • The Fiber/Metal Laminates (FMLs) have been developed as a new composite material for aerospace application to reduce weight and improve damage tolerance. In this study, firstly FMLs were manufactured and the tensile test was performed to investigate the mechanical properties of FMLs. Furthermore, impact behavior of the low velocity on FMLs which consisted of different types of aluminum or fiber/epoxy layers was tested by the drop weight impact tester based on the different impact energy conditions. The load-time and energy-time curves were employed to evaluate the impact performance of different specimens. Moreover, finite element analysis (FEA) was also performed to simulate the tensile test and impact behavior of FMLs under the same conditions with the tests and good agreements have been obtained between the FEA predictions and experimental results.

Characteristics of Low Velocity Impact Responses due to Interface Number and Stacking Sequences of CFRP Composite Plates (CFRP 복합적층판의 적층배향.계면수에 따른 저속충격특성)

  • Im, Kwang-Hee;Park, No-Sick;Ra, Seung-Woo;Kim, Young-Nam;Lee, Hyun;Sim, Jae-Ki;Yang, In-Young
    • Transactions of the Korean Society of Machine Tool Engineers
    • /
    • v.10 no.6
    • /
    • pp.48-56
    • /
    • 2001
  • In this paper, this study aims at the evaluation on the characteristics of CFRP laminate plates using a falling weight impact tester. The experiment was conducted on several laminates of different orientation. A system was built far measur- ing the impact strength of CFRP laminates in consideration of stress wave propagation theory using a falling weight impact tester. Delamination areas of impacted specimens for the different ply orientation were measured with ultrasonic C- scanner to find correlation between impact energy and delamination area. Absorbed energy of quasi-isotropic specimen having flour interfaces was higher than that of orthotropic laminates with two interfaces. The more interfaces, the greater the energy absorbed. The absorbed energy oft hybrid specimen containing a GFRP layer was higher than that of normal specimens.

  • PDF

Study on the Dynamic Response Characteristics of Impact Force Sensors Based on the Strain Gage Measurement Principle (변형률 게이지 측정원리를 이용한 충격하중 측정 센서의 동적응답 특성에 관한 연구)

  • Ahn, Jung-Lyang;Kim, Seung-Kon;Sung, Nak-Hoon;Song, Young-Soo;Cho, Sang-Ho
    • Explosives and Blasting
    • /
    • v.29 no.1
    • /
    • pp.41-47
    • /
    • 2011
  • In order to estimate blast damage zone and control rock fragmentation in blasting, it is important to obtain information regarding blast hole pressure. In this study, drop impact tests of acrylic, aluminium, steel sensors were performed to investigate the dynamic response characterizations of the sensors through the strain signals. As a result, the strain signals obtained from the steel sensors showed less sensitivity to impact force level and experienced small changes with various length of the sensors. The steel sensors were applied to measure the impact force of an electric detonator.

Influence of Fiber Strength and Stacking Sequences on Impact Damages of CFRP Composites (섬유강도와 적층구성이 CFRP적층판의 충격손상에 미치는 영향)

  • 임광희;박노식;양인영
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.9 no.3
    • /
    • pp.210-220
    • /
    • 2001
  • This paper aims at the evaluation on the characterization of CFRP laminate plates using falling weight impact tester. The experimentation was conducted on several laminates of different fiber and ply orientation. A system was built for the impact strength of CFRP laminates in consideration of stress wave propagation with using drop-weight impact tester as one of impact test. Absorbed energy of orthotropic composites with using T300 fiber, which are composed of the same fiber and stacking number is higher than that or quasi-isotropic specimen over impact energy 7J, but in case or using T700 fiber, much difference does not show. Also, absorbed energy of orthotropic composites with using T300 fiber, which are composed or stacking number and orientation became more than that of T700 fiber specimen; however great change doesn't show in case of quasi-isotropic specimens. It is found that influence was confirmed between impact energy and absorbed energy as the impact energy is increased with adding the falling weight.

  • PDF

Development of Low-Velocity Impact Analysis Model of Carbon-Steel Laminates through Finite Element Analysis (유한요소해석을 통한 탄소섬유-연강 적층판의 저속 충격 해석 모델 개발)

  • Park, Byung-Jin;Lee, Dong-Woo;Song, Jung-Il
    • Composites Research
    • /
    • v.31 no.5
    • /
    • pp.215-220
    • /
    • 2018
  • In this study, finite element analysis of Carbon-Steel Laminates with different layup pattern was conducted to verify similarity to the results of previous studies and to develop the effective model for low-velocity impact analysis. As in the experiment, Finite element analysis of the Fiber metal laminates (FMLs) with five different lamination patterns was carried out, and the impact resistance of the FMLs was confirmed by comparing the energy absorption ratio. The FMLs showed the higher energy absorption ratio than the mild steel having the same thickness, and it was confirmed that all the FMLs had the high energy absorption ratio over than 96%. In addition, the low-velocity impact analysis model proposed in this study can be effectively used to study composite forms and automotive structures.

The Impact fracture Behaviors of Low Density LD Carbon/Carbon Composites by Drop Weight Impact Test (낙하 충격 시험에 의한 저밀도 2-D탄소/탄소 복합재의 충격파괴거동)

  • 주혁종;손종석
    • Polymer(Korea)
    • /
    • v.26 no.2
    • /
    • pp.270-278
    • /
    • 2002
  • In this study, the fracture behavior by low velocity impact damage and the tendencies of impact energy absorption were investigated. Low velocity impact tests were performed using a mini tower drop weight impact tester, and graphite powder, carbon black and milled carton fiber were chosen as additives. Addition of graphite powder increased the maximum load and maintained the stress long until the total penetration happened. At the content of 9 vol%, they showed the maximum of 42% improvement in impact strength compared composites containing no additives. At the test with low impact energy of 0.4 J, impact energy was consumed by delamination in the composite containing no additives, however, as graphite contents increased, the tendency of failure changed to the penetration of the specimen.