• Title/Summary/Keyword: 홉킨슨 바 시험기

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Parameter Study for the Analysis of Impact Characteristics considering Dynamic Material Properties (동적 물성치를 고려한 V.I. 충격인자의 영향 분석)

  • Lim, J.H.;Song, J.H.;Huh, H.;Park, W.J.;Oh, I.S.;Choe, J.W.
    • Proceedings of the KSME Conference
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    • 2001.06a
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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.

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Dynamic Material Test of Sinter-Forged Cu-Cr Alloy and Application to the Impact Characteristics of Vacuum Interrupter (구리-크롬 합금의 조성비에 따른 동적실험 및 진공 인터럽터 충격특성에의 적용)

  • Song, Jung-Han;Lim, Ji-Ho;Huh, Hoon
    • Proceedings of the KSME Conference
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    • 2004.11a
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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.

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Parameter Study of Impact Characteristics for a Vacuum Interrupter Considering Dynamic Material Properties (동적 물성치를 고려한 진공 인터럽터 충격특성의 영향인자 분석)

  • Lim, Ji-Ho;Song, Jeong-Han;Huh, Hoon;Park, Woo-Jin;Oh, Il-Seong;Ahn, Gil-Young;Choe, Jong-Woong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.5
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    • pp.924-931
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    • 2002
  • 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 the high strain rate is obtained from the split Hopkinson pressure bar test using disc-type specimens. 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 value of five parameters such as the initial velocity of a movable electrode, the added mass of a movable electrode, the wipe spring constant, initial offset of a wipe spring and the virtual fixed spring constant.