• Title, Summary, Keyword: SHPB(Split Hopkinson Pressure Bar)

Search Result 65, Processing Time 0.066 seconds

Split Hopkinson Pressure Bar(SHPB)에 의한 고 변형률 재료의 구성방정식 시뮬레이션

  • 이억섭;정주호;김종호
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • /
    • pp.724-727
    • /
    • 1995
  • Dynamic deformation behavior under the high strain rate loading condition obtained with the aid of Split Hopkinson Pressure Bar(SHPB) technique is simulated by DYNA2D (an hydrodynamic code). A constitutive equation such as Johnson-Cook model is used by adjusting various parameters to fit experimentally determined dynamic stress-strain relationship.

  • PDF

Effect of pulse shaper in SHPB technique on dynamic deformation behavior of an NBR rubber (SHPB 기법에서 Pusle shpaer 가 내유 고무(NBR)의 동적 변형 거동에 미치는 영향)

  • 김성현;이억섭;이종원
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • /
    • pp.634-637
    • /
    • 2004
  • This paper presents a Split Hopkinson Pressure Bar(SHPB) technique to obtain compressive stress-strain data for rubber materials. An experimental technique that modifies the conventional Split Hopkinson Pressure Bar(SHPB) has been developed for measuring the compressive stress-strain responses of materials with low mechanical impedance and low compressive strengths such as rubber. This paper introduces an all-polymeric pressure bar which achieves a closer impedance match between the pressure bar and the specimen materials. In addition, we are a pulse shaper to lengthen the rising time of the incident wave to ensure stress equilibrium and homogeneous deformation of a rubber materials. It is found that the modified technique can be determine the dynamic deformation behavior of an NBR rubber more accurately.

  • PDF

Design and Fabrication of Split Hopkinson Pressure Bar for Acquisition of Dynamic Material Property of Al6061-T6 (Al6061-T6 의 동적 물성 획득을 위한 Split Hopkinson Pressure Bar의 설계 및 제작)

  • An, Woo Jin;Woo, Min A;Noh, Hak Gon;Kang, Beom Soo;Kim, Jeong
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.33 no.7
    • /
    • pp.587-594
    • /
    • 2016
  • The Split Hopkinson pressure bar (SHPB) test method, which is composed of three cylindrical bars, measuring devices and frames, is known for its reliable technique of acquiring the mechanical properties of specimens under a high strain rate. This paper demonstrates the processing of design and fabrication of SHPB. First of all, numerical analysis is applied in order to determine the design parameters of SHPB apparatus and verify the validity of design for a SHPB facility. Following this, SHPB apparatus were fabricated in accordance with acquired design parameters by simulation. In order to verify the validity of SHPB apparatus, experimental results using Al6061-T6 were compared with numerical data obtained from a corresponding simulation. The result of this comparative study demonstrates the applicability and validity of the fabricated apparatus.

Adaptation of impactor for the split Hopkinson pressure bar in characterizing concrete at medium strain rate

  • Zhao, Pengjun;Lok, Tat-Seng
    • Structural Engineering and Mechanics
    • /
    • v.19 no.6
    • /
    • pp.603-618
    • /
    • 2005
  • The split Hopkinson pressure bar (SHPB) technique is widely used to characterize the dynamic mechanical response of engineering materials at high strain rates. In this paper, attendant problems associated with testing 70 mm diameter concrete specimens are considered, analysed and resolved. An adaptation of a conventional solid circular striker bar, as a means of achieving reliable and repeatable SHPB tests, is then proposed. In the analysis, a pseudo one-dimensional model is used to analyse wave propagation in a non-uniform striker bar. The stress history of the incident wave is then obtained by using the finite difference method. Comparison was made between incident waves determined from the simplified model, finite element solution and experimental data. The results show that the simplified method is adequate for designing striker bar shapes to overcome difficulties commonly encountered in SHPB tests. Using two specifically designed striker bars, tests were conducted on 70 mm diameter steel fibre reinforced concrete specimens. The results are presented in the paper.

An Investigation into the effect of friction in the split hopkinson pressure bar (SHPB) test by numerical experiments (수치해석을 이용한 SHPB 시험의 마찰영향 분석)

  • Cha, Sung-Hoon;Shin, Myoung-Soo;Shin, Hyun-Ho;Kim, Jong-Bong
    • Proceedings of the KSME Conference
    • /
    • /
    • pp.204-209
    • /
    • 2008
  • The interest in the mechanical behavior of materials at high strain rates has increased in recent years, and by now it is well known that mechanical properties can be strongly influenced by the speed of applied load. The split Hopkinson pressure bar (SHPB) has been widely used to determine mechanical properties of materials at high loading rates. However, to ensure test reliability, measurement error source must be accounted for and eliminated. During experiment, the specimens were located between the incident and the transmit bar. The presence of contact frictions between the test bars and specimen may cause errors. In this work, numerical experiments were carried out to investigate the effect of friction on test results. In SHPB test, the measured stress by the transmitted bar is assumed to be flow stress of the test specimen. Through the numerical experiments, however, it is shown that the measured stress by the transmit bar is axial stress components. When, the contact surface is frictionless, the flow stress and the axial stress of the specimen are about the same. When the contact surface is not frictionless, however, the flow stress and the axial stress are not the same anymore. Therefore, the measured stress by the transmitted bar is not flow stress. The effect of friction on the difference between flow stress and axial stress is investigated.

  • PDF

Design and Fabrication of Split Hopkinson Pressure Bar for Dynamic Mechanical Properties of Self-reinforced Polypropylene Composite (폴리프로필렌 자기 보강 복합재의 동적 물성 구축을 위한 Split Hopkinson Pressure Bar의 설계 및 제작)

  • Kang, So-Young;Kim, Do-Hyoung;Kim, Dong-Hyun;Kim, Hak-Sung
    • Composites Research
    • /
    • v.31 no.5
    • /
    • pp.221-226
    • /
    • 2018
  • The Split Hopkinson Pressure Bar(SHPB) has been the most widely used apparatus to characterize dynamic mechanical behavior of materials at high strain rates between $100s^{-1}$ and $10,000s^{-1}$. The SHPB test is based on the wave propagation theory which was developed to give the stress, strain and strain rate in the specimen using the strains measured in the incident and transmission bars. In this study, the SHPB was directly designed and fabricated for the dynamic mechanical properties of fiber reinforced plastic (FRP) composites. In addition, this apparatus was verified for the validity by comparing the strain data obtained through the high speed camera and Digital Image Correlation(DIC) during the high strain rate compression test of the self-reinforced polypropylene composite (SRPP) specimen.

Dynamic tensile behavior of PMMA (PMMA의 동적 인장 거동)

  • Lee, Ouk-Sub;Kim, Myun-Soo;Hwang, Si-Won
    • Proceedings of the KSME Conference
    • /
    • /
    • pp.395-400
    • /
    • 2001
  • The Split Hopkinson Pressure Bar(SHPB) technique, a special experimental apparatus, has been used to obtain the material behavior under high strain rate loading condition. In this paper, dynamic deformation behaviors of the PMMA under high strain rate tensile loading are determined using SHPB technique.

  • PDF

Dynamic deformation behavior of rubber under high strain rate compressive loading (플라스틱 SHPB를 사용한 고무의 고변형률 하중하에서의 동적변형 거동)

  • 이억섭;김경준
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • /
    • pp.849-853
    • /
    • 2002
  • 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. 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.

  • PDF

Dynamic Deformation Behavior of Rubber and Ethylene Copolymer Under High Strain Rate Compressive Loading (SHPB기법을 사용한 고무와 합성수지의 고변형률 속도 하중 하에서의 동적 변형 거동)

  • 이억섭;이종원;김경준
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.21 no.6
    • /
    • pp.122-130
    • /
    • 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.

High-Strain-Rate Deformation of Fe-6.5wt.%Si Alloys using a Split Hopkinson Pressure Bar Technique (홉킨슨 압력봉법을 이용한 Fe-6.5wt.%Si 합금의 고변형률속도 거동)

  • Yoon, Young-Ki;Yoon, Hi-Seak;Umakoshi, Yukichi;Yasuda, Hiroyuki Y.
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.25 no.7
    • /
    • pp.1073-1081
    • /
    • 2001
  • Many researches have published numerous papers about the high-strain-rate obtained from Split Hopkinson Pressure Bar(SHPB) tests. And 6.5wt%Si steel is widely known as an excellent magnetic material because its magnetostriction is nearly zero. Single crystals are prepared by the Floating Zone(FZ) method, which melts the alloy by the use of a high temperature electron beam in a pure argon gas condition. In this paper, the fracture behavior of the poly crystals and single crystals (DO$_3$phase) of Fe-6.5wt%Si alloy by SHPB test is observed. The comparison of high-strain-rate results with static results was done. Obtained main results are as follows: (1) Fe-6.5wt%Si alloy has higher strength at high-strain-rate tensile. SHPB results of polycrystal are twice as high as static results. (2) From the fractography, the cleavage steps are remarkably reduced in the SHPB test compared with the static test.