• 한국정밀공학회지
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• 제21권6호
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• pp.122-130
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• 2004

It is well known that a specific experimental method, the Split Hopkinson Pressure Bar (SHPB) technique is a best experimental technique to determine the dynamic material properties under the impact compressive loading conditions with strain-rate of the order of 10$^3$/s∼10$^4$/s. This type of experimental procedure has been widely used with proper modification on the test setups to determine the varying dynamic response of materials for the dynamic boundary conditions such as tensile and fracture as well. In this paper, dynamic compressive deformation behaviors of a rubber and an Ethylene Copolymer materials widely used for the isolation of vibration from varying structures under dynamic loading are estimated using a Split Hopkinson Pressure Bar technique.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1491-1494
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• 2003

A specific experimental method, the Split Hopkinson Pressure Bar (SHPB) technique has been widely used to determine the dynamic material properties under the impact compressive loading conditions with strain-rate of the order of 103/s∼104/s. This type of test procedure has been used to examine the dynamic response of materials in various modes of testing. In this paper, dynamic deformation behaviors of rubber materials widely used for the isolation of vibration from varying structures under dynamic loading are determined using a Split Hopkinson Pressure Bar technique.

• 대한기계학회논문집A
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• 제24권8호
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• pp.1917-1922
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• 2000

The split Hokinson pressure bar(SHPB) test has been used to find the mechanical property of materials at high strain rate. A tensile split Hopkinson pressure bar test system is developed and the threaded tensile specimen and the split collar are placed between elastic bars. When the compressive elastic wave generated by a striker is transferred from the transmit bar to the incident bar, some elastic wave is reflected at the threaded parts of the specimen and the transmit bar. This reflected wave can interfere with the transmitted wave. A proper length of elastic bars and the location of strain gage in these elastic bars are determined to avoid this interference. In order to avoid the interference of elastic wave reflected at the threaded parts of specimen and elastic bar, the length of transmit bar must be longer than that of incident bar. Strain gage in transmit bar must be located as close as possible from the interface of a transmit bar and specimen. In the developed tensile SHPB test system, A12011-T3 and A17075-T6 are tested to get the true stress-strain relation in the range of strain rate at $10^3/sec$

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.371-376
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• 2004

It is well known that a specific experimental method such as the Split Hopkinson Pressure Bar (SHPB) technique is the simplest experimental technique to determine the dynamic material properties under the impact compressive loading conditions with strain-rate of the order of $10^3/s{\sim}10^4/s$. This type of experimental procedure has been widely used with proper modification on the test setups to determine the varying dynamic response of materials for the dynamic boundary conditions such as tensile and fracture as well. In this paper, dynamic compressive deformation behaviors of an Ethylene Copolymer materials widely used for the isolation of vibration from varying structures under dynamic loading are estimated using the SHPB technique.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.945-950
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• 2001

Vacuum interrupters that is used in various switchgear components such as circuit breakers, distribution switches, contactors, etc. spreads the arc uniformly over the surface of the contacts. The electrode of vacuum interrupters is used sintered Cu-Cr material satisfied with good electrical and mechanical characteristics. Because the closing velocity is 1-3m/s, the deformation of the material of electrodes depends on the strain rate and the dynamic behavior of the sintered Cu-Cr material is a key to investigate the impact characteristics of the electrodes. The dynamic response of the material at the high strain-rate is obtained from the split Hopkinson pressure bar test using cylinder type specimens. Experimental results from both quasi-static and dynamic compressive tests with the split Hopkinson pressure bar apparatus are interpolated to construct the Johnson-Cook equation as the constitutive relation that should be applied to simulation of the dynamic behavior of electrodes. To evaluate impact characteristic of a vacuum interrupter, simulation is carried out with five parameters such as initial velocity, added mass of a movable electrode, wipe spring constant, initial offset of a wipe spring and virtual fixed spring constant.

• Composites Research
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• 제35권1호
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• pp.38-41
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• 2022

고 변형률 속도에서 폴리프로필렌-유리 장섬유 복합재료(PP-LGF)와 열가소성 올레핀(TPO) 소재의 동적 압축 특성을 얻기 위해 홉킨슨바(Split-Hopkinson Pressure Bar (SHPB))를 이용하여 실험을 진행하였다. SHPB는 변형률 속도 100 s^-1~10000 s^-1 범위에서 재료의 동적 기계적 물성을 확인할 수 있는 장치이다. SHPB 시험은 입력봉과 전달봉에서 측정된 탄성파를 이용하여 시편의 응력, 변형률 및 변형률 속도를 얻을 수 있는 탄성파 전달 이론을 기반으로 한다. 또한 SHPB에서 얻은 변형률 데이터의 검증을 위해 시편을 초고속카메라로 촬영하여 DIC 기법을 통해 얻은 변형률 데이터와 비교 진행하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.795-798
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• 1997

This study is about the dynamic behavior of steel(SM45C). Dynamic tests were performed using SHPB(Split Hopkinson Pressure Bar) which is designed and modified to be used in both tensile and compressive modes. Quasi-static compression tests were also carried out for the comparison to the dynamic results. Not only the dynamic mechanical properties but also the effect of the notch of the specimen on stress-strain curve were investigated. The dynamic test results reveal that strain and stress are sensitively affected by the notch. The depth and the number of notch increase the stress and decrease the strain.

• Structural Engineering and Mechanics
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• 제37권1호
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• pp.1-15
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• 2011

The response of concrete to transient dynamic loading has received extensive attention for both civil and military applications. Accordingly, thoroughly understanding the response and failure modes of concrete subjected to impact or explosive loading is vital to the protection provided by fortifications. Reactive powder concrete (RPC), as developed by Richard and Cheyrezy (1995) in recent years, is a unique mixture that is cured such that it has an ultra-high compressive strength. In this work, the concrete cylinders with different steel fiber volume fractions were subjected to repeated impact loading by a split Hopkinson Pressure Bar (SHPB) device. Experimental results indicate that the ability of repeated impact resistance of ultra-high-strength concrete was markedly superior to that of other specimens. Additionally, the rate of damage was decelerated and the energy absorption of ultra-high-strength concrete improved as the steel fiber volume fraction increased.

• 한국구조물진단유지관리공학회 논문집
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• 제19권4호
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• pp.83-91
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• 2015

충돌 또는 폭발 하중 하의 콘크리트는 정적 하중에서 가지는 재료물성과 다른 거동을 보이게 된다. 즉, 고변형율 하의 콘크리트의 재료물성은 크게 변화하게 되며, 이를 시험평가하기 위한 방법 중 압축강도와 관련된 시험법으로는 SHPB(Split Hopkinson Pressure Bar) Test가 있다. 그러나, SHPB Test는 금속과 같은 인성재료를 위해 개발된 시험방법으로서 취성재료인 콘크리트에 적용이 가능한지에 대한 검토가 추가적으로 필요하며, UHPC와 같은 섬유보강 초고성능 콘크리트에 대한 연구는 미미한 실정이다. 이에 본 연구에서는 콘크리트 시험체를 위해 제작된 SHPB Test 장비를 사용하여 일반 콘크리트 및 UHPC 시험체에 대한 시험평가를 수행하였으며, SHPB Test의 적용 적정성을 파악하기 위하여 초고속카메라를 활용한 변위영상 분석을 통한 검증을 수행하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.447-452
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• 2004

Vacuum interrupters in order to be used in various switch-gear components such as circuit breakers, distribution switches, contactors, etc. spread the arc uniformly over the surface of the contacts. The electrodes of vacuum interrupters are made of sinter-forged Cu-Cr materials for good electrical and mechanical characteristics. Since the closing velocity is 1-2m/s and impact deformation of the electrode depends on the strain rate at that velocity, the dynamic behavior of the sinter-forged Cu-Cr is a key to investigate the impact characteristics of the electrodes. The dynamic response of the material at intermediate strain rate is obtained from the high speed tensile test machine test and at the high strain rate is obtained from the split Hopkinson pressure bar test. Experimental results from both quasi-static and dynamic compressive tests are interpolated to construct the Johnson-Cook model as the constitutive relation that should be applied to simulation of the dynamic behavior of the electrodes. The impact characteristics of a vacuum interrupter are investigated with computer simulations by changing the amount of chromium content.