• 제목/요약/키워드: dynamic compressive behavior

검색결과 112건 처리시간 0.023초

고변형률 압축 하중에서 쾌삭 황동과 황동의 동적 변형 거동 특성 (Dynamic Compressive Deformation Characteristics of Free-Cutting Brass And Yellow Brass at High Strain Rates)

  • 이억섭;김경준;이종원
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2003년도 춘계학술대회
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    • pp.107-112
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    • 2003
  • Mechanical properties of the materials used for transportations and industrial machinery under high strain rate loading conditions such as high impact loading are required to provide appropriate safety assessment to varying dynamically loaded mechanical structures. The Split Hopkinson Pressure Bar(SHPB) technique with a special experimental apparatus can be used to obtain the material behavior under high strain rate loading conditions. In this paper, the dynamic deformation behavior of a brass under both high strain rate compressive loading conditions has been determined using the SHPB technique.

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고변형률 압축 하중에서 활동(KS D 5101 C3605BD-F)의 동적 변형 거동 특성 (Dynamic Compressive Deformation Characteristics of Brass at High Strain Rates)

  • 이억섭;나경찬;김경준
    • 한국정밀공학회지
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    • 제20권12호
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    • pp.142-147
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    • 2003
  • Mechanical properties of the materials used for transportations and industrial machinery under high strain rate loading conditions such as high impact loading are required to provide appropriate safety assessment to varying dynamically leaded mechanical structures. The Split Hopkinson Pressure Bar(SHPB) technique with a special experimental apparatus can be used to obtain the material behavior under high strain rate ]ending conditions. In this paper, the dynamic deformation behavior of a brass under both high strain rate compressive loading conditions has been determined using the SHPB technique.

고변형률 속도 압축 하중 하에서의 고무와 황동의 동적 거동 특성 (Dynamic deformation behavior of rubber and brass under high strain rate compressive loading)

  • 이억섭;김경준;이종원
    • 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.

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압축강도 수준에 따른 HPFRCC의 동적충격 인장강도 평가 (Evaluation of Dynamic Tensile Strength of HPFRCC According to Compressive Strength Level)

  • 박기준;김원우;박정준;문재흠;김성욱
    • 한국구조물진단유지관리공학회 논문집
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    • 제22권3호
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    • pp.31-37
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    • 2018
  • 이 논문은 압축강도 수준(100, 140, 180 MPa급)에 따른 HPFRCC의 동적충격 인장강도를 평가하였다. 먼저 100, 140, 180 MPa급 HPFRCC의 압축응력-변형률 관계를 분석한 결과 압축강도는 각각 112, 150, 202 MPa로 나타났으며, 압축강도가 높아짐에 따라 탄성계수도 증가하는 경향을 나타내었다. 100, 140, 180 MPa급 HPFRCC의 정적 인장강도는 각각 10.7, 11.5, 16.5 MPa로 나타났으며, 압축강도가 높아질수록 인장강도도 증가하는 경향을 나타내었다. 반면 100 및 140 MPa급 HPFRCC에서의 인장강도 및 에너지 흡수능력은 압축강도 수준에 따라 큰 차이를 보이지 않았다. 이는 시험체의 규격 및 강섬유의 배열에 영향을 받은 것으로 판단된다. HPFRCC의 동적충격 인장강도를 평가한 결과, 변형률 속도가 10-1/s에서 150/s로 증가할수록 모든 HPFRCC의 인장강도와 동적증가계수는 증가하는 경향을 보였다. 한편 동일한 범위의 변형률 속도에서 HPFRCC의 압축강도가 낮을수록 인장강도에 대한 DIF가 높게 측정되어 효율적인 측면에서는 100 MPa급 HPFRCC가 가장 우수한 것으로 나타났다. 따라서 높은 수준의 인장성능이 요구되는 경우 높은 압축강도를 가지는 HPFRCC를 사용하는 것이 유리하며, 폭발과 같은 고속변형률 속도에서 보다 효율적인 접근을 위해서는 목표 압축강도에 근접한 HPFRCC를 사용하는 것이 바람직한 것으로 판단된다.

Factors governing dynamic response of steel-foam ceramic protected RC slabs under blast loads

  • Hou, Xiaomeng;Liu, Kunyu;Cao, Shaojun;Rong, Qin
    • Steel and Composite Structures
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    • 제33권3호
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    • pp.333-346
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    • 2019
  • Foam ceramic materials contribute to the explosion effect weakening on concrete structures, due to the corresponding excellent energy absorption ability. The blast resistance of concrete members could be improved through steel-foam ceramics as protective cladding layers. An approach for the modeling of dynamic response of steel-foam ceramic protected reinforced concrete (Steel-FC-RC) slabs under blast loading was presented with the LS-DYNA software. The orthogonal analysis (five factors with five levels) under three degrees of blast loads was conducted. The influence rankings and trend laws were further analyzed. The dynamic displacement of the slab bottom was significantly reduced by increasing the thickness of steel plate, foam ceramic and RC slab, while the displacement decreased slightly as the steel yield strength and the compressive strength of concrete increased. However, the optimized efficiency of blast resistance decreases with factors increase to higher level. Moreover, an efficient design method was reported based on the orthogonal analysis.

Ti-6Al-4V 합금의 동적 변형 거동에 관한 연구 (A Study on the Dynamic Behavior of Ti-6Al-4V Alloy)

  • 서용석;이영신;송오섭
    • 한국군사과학기술학회지
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    • 제20권2호
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    • pp.206-216
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    • 2017
  • This paper studies on the dynamic properties of Ti-6Al-4V alloy. After forming the four different micro structures(equiaxed, lamellar, and 2 bimodals) through heat treatments, static and dynamic properties of each structure were investigated quantitatively. Dynamic behaviors of the alloy are observed by the compressive split Hopkinson pressure bar(SHPB) tests. In additon, parameters of Johnson-Cook equation were determined from the SHPB test results. In order to verify the suitability of the parameters, high velocity impact tests were performed and the results were compared with the numerical analysis results. Although the flow stress and the fracture strain of the bimodal structures were higher than those of the equiaxed structure at the static tests, the superior dynamic properties were observed at the equiaxed structure due to the effects of higher maximum flow stress and fracture strain. From the numerical analysis, J-C parameters which are determined on this study describe well the dynamic behavior of Ti-6Al-4V alloy. Experimental and analysis results are consistent with ${\pm}5%$ of an average error.

고변형률 압축/인장 하중에 대한 알루미늄 합금의 동적 변형 거동 (Dynamic Deformation Behavior of Aluminum Alloys under High Strain Rate Compressive/Tensile Loading)

  • 이억섭;김면수;황시원;조규상
    • 한국정밀공학회지
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    • 제20권1호
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    • pp.196-204
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    • 2003
  • Mechanical properties of the materials used for transportations and industrial machinery under high strain rate loading conditions such as seismic loading are required to provide appropriate safety assessment to these mechanical structures. The split Hopkinson Pressure Bar (SHPB) technique with a special experimental apparatus can be used to obtain the material behavior under high strain rate loading conditions. In this paper, dynamic deformation behaviors of the aluminum alloys such as A12024-T4, A16061-T6, and A17075-T6 under both high strain rate compressive and tensile loading conditions are determined using the SHPB technique.

A numerical study on the damage of projectile impact on concrete targets

  • Lu, Gang;Li, Xibing;Wang, Kejin
    • Computers and Concrete
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    • 제9권1호
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    • pp.21-33
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    • 2012
  • This paper presents the numerical simulation of the rigid 12.6 mm diameter kinetic energy ogive-nosed projectile impact on plain and fiber reinforced concrete (FRC) targets with compressive strengths from 45 to 235 MPa, using a three-dimensional finite element code LS-DYNA. A combined dynamic constitutive model, describing the compressive and tensile damage of concrete, is implemented. A modified Johnson_Holmquist_Cook (MJHC) constitutive relationship and damage model are incorporated to simulate the concrete behavior under compression. A tensile damage model is added to the MJHC model to analyze the dynamic fracture behavior of concrete in tension, due to blast loading. As a consequence, the impact damage in targets made of plain and fiber reinforced concrete with same matrix material under same impact velocities (650 m/s) are obtained. Moreover, the damage distribution of concrete after penetration is procured to compare with the experimental results. Numerical simulations provide a reasonable prediction on concrete damage in both compression and tension.

고속충격하의 노치형상에 따른 동적거동연구 (A study of dynamic behavior with effect of notch shape on high impact)

  • 장영환;박성도;윤희석
    • 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.

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Dynamic Compressive Creep of Extruded Ultra-High Molecular Weight Polyethylene

  • Lee, Kwon-Yong;David Pienkowski;Lee, Sungjae
    • Journal of Mechanical Science and Technology
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    • 제17권9호
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    • pp.1332-1338
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    • 2003
  • To estimate the true wear rate of polyethylene acetabular cups used in total hip arthroplasty, the dynamic compressive creep deformation of ultra-high molecular weight polyethylene (UHMWPE) was quantified as a function of time, load amplitude, and radial location of the specimen in the extruded rod stock. These data were also compared with the creep behavior of polyethylene observed under static loading. Total creep strains under dynamic loading were only 64%, 70%, and 61% of the total creep strains under static loading at the same maximum pressures of 2 MPa,4 MPa, and 8 MPa, respectively. Specimens cut from the periphery of the rod stock demonstrated more creep than those cut from the center when they were compressed in a direction parallel to the extrusion direction (vertical loading) whereas the opposite was observed when specimens were compressed in a direction perpendicular to the extrusion direction (transverse loading). These findings show that creep deformation of UHMWPE depends upon the orientation of the crystalline lamellae.