• 제목/요약/키워드: strain plane

검색결과 993건 처리시간 0.028초

레이저 스페클을 이용한 재료 변형 측정 (Measurement of Material Deformation Using Laser Speckle)

  • 전문창;강기주
    • 한국정밀공학회:학술대회논문집
    • /
    • 한국정밀공학회 2002년도 춘계학술대회 논문집
    • /
    • pp.688-694
    • /
    • 2002
  • As a tool for strain measurement to work with screw driven or hydraulic material test systems, in which mechanical vibration is inherent, SSDG(Speckle Strain/Displacement Gage), ESP(Electronic Speckle Photography) and its 3-dimension version SDSP are investigated for the theory and practical appliance. Through tension test of steel strips, their validity and shortcomings are examined. As the results, it has been shown that, although SSDG and ESP provide direct measurement of in-plane strain in one direction, they are so sensitive to the out-plane displacement. On the other hand, SDSP which is aided with DIC (Digital Image Correlation) technique to trace the movement of the speckles provides not only in-plane 2-dimensional displacement field, but also out-of-plane displacement simultaneously. However, because the DIC is time-consuming, not automated yet and it needs post-processing to evaluate strain from the displacement field, SDSP appears to be not adequate as a real time sensor.

  • PDF

마이크로 ESPI 기법에 의한 면내 변형 측정 민감도 향상 (Improvement of Sensitivity to In-plane Strain/Deformation Measurement by Micro-ESPI Technique)

  • 김동일;허용학;기창두
    • 한국정밀공학회:학술대회논문집
    • /
    • 한국정밀공학회 2005년도 춘계학술대회 논문집
    • /
    • pp.1442-1445
    • /
    • 2005
  • Several test methods, including micro strain/deformation measurement techniques, have been studied to more reliably measure the micro properties in micro/nano materials. Therefore, in this study, the continuous measurement of in-plane tensile strain in micro-sized specimens of thin film materials was introduced using the micro-ESPI technique. TiN and Au thin films 1 and $0.47\;\mu{m}$ thick, respectively, were deposited on the silicon wafer and fabricated into the micro-sized tensile specimens using the electromachining process. The micro-tensile loading system and micro-ESPI system were developed to measure the tensile strain during micro-tensile test. The micro-tensile stress-strain for these materials was determined using the algorithm for continuous strain measurement. Furthermore, algorithm for enhancing the sensitivity to measurement of in-plane tensile strain was suggested. According to the algorithm for enhancement of sensitivity, micro-tensile strain data between interfringe were calculated. It is shown that the algorithm for enhancement of the sensitivity suggested in this study makes the sensitivity to the in-plane tensile strain increase.

  • PDF

측면홈 시험편을 이용한 평면 변형률 피로 균열 진전에 관한 연구 (Investigation of Plane Strain Fatigue Crack Growth Behavior by Using Side-Grooved Specimens)

  • 김종한;송지호
    • 대한기계학회논문집
    • /
    • 제16권1호
    • /
    • pp.63-69
    • /
    • 1992
  • 본 연구에서는 특히 앞서 지적한 표면균열의 진전거동에 관한 연구와도 관련 하여 측면홈을 가진 중앙관통균열(side-grooved center cracked tension) 시험편에 대 해 피로균열 진전실험을 수행하고, 평면변형률 조건의 만족여부 및 응력강도계수 평가 방법에 관하여 검토하여 비교적 새로운 결과를 얻었으므로 여기에 보고하고자 한다.

생체 모방 종이 작동기의 면내 변형에 관한 연구 (Study on In-plane Strains of Electro-Active Paper)

  • 정우철;김재환;이선곤;배성훈
    • 한국소음진동공학회:학술대회논문집
    • /
    • 한국소음진동공학회 2005년도 추계학술대회논문집
    • /
    • pp.727-730
    • /
    • 2005
  • Cellulose based Electro-Active Papers (EAPap) is very promising material due to its merits in terms of large bending deformation, low actuation voltage, ultra-lightweight, and biodegradability. These advantages make it possible to utilize applications, such as artificial muscles and achieving flapping wings, micro-insect robots and smart wall papers. This paper investigates the in-plane strains of EAPap under electric fields, which are useful for a contractile actuator application The preparation of EAPap samples and the in-plane strain measurement system are explained, and the test results are shown in terms of electric field, frequency and the oriental ions of the samples. The power consumption and the strain energy of EAPap samples are discussed. Although there are still unknown facts in EAPap material, this in-plane strain may be useful for artificial muscle applications.

  • PDF

레이저 스페클과 디지털 화상관련법을 이용한 변위 측정방법의 평가 (Evaluation of Displacement Measurement Technique Using Laser Speckle and Digital Image Correlation Method)

  • 강기주;이정현;전문창
    • 한국정밀공학회지
    • /
    • 제20권6호
    • /
    • pp.47-54
    • /
    • 2003
  • As a tool for strain measurement to work with screw driven or hydraulic material test systems, in which mechanical vibration is inherent, SSDG (Speckle Strain/Displacement Gage), ESP (Electronic Speckle Photography) and its 3-dimension version SDSP are evaluated for the theory and practical appliance. Through tension test of steel strips, their validity and shortcomings are examined. As the results, it has been shown that, although SSDG and ESP provide direct measurement of in-plane strain in one direction, they are so sensitive to the out-plane displacement. On the other hand, SDSP which is aided with DIC (Digital Image Correlation) technique to trace the movement of the speckles provides not only in-plane 2-dimensional displacement field, but also out-of-plane displacement simultaneously. However, because the DIC is time-consuming, not automated yet and it needs post-processing to evaluate strain from the displacement field, SDSP appears to be not adequate as a real time sensor.

Localized deformation in sands and glass beads subjected to plane strain compressions

  • Zhuang, Li;Nakata, Yukio;Lee, In-Mo
    • Geomechanics and Engineering
    • /
    • 제5권6호
    • /
    • pp.499-517
    • /
    • 2013
  • In order to investigate shear behavior of granular materials due to excavation and associated unloading actions, load-controlled plane strain compression tests under decreasing confining pressure were performed under drained conditions and the results were compared with the conventional plane strain compression tests. Four types of granular material consisting of two quartz sands and two glass beads were used to investigate particle shape effects. It is clarified that macro stress-strain behavior is more easily influenced by stress level and stress path in sands than in glass beads. Development of localized deformation was analyzed using photogrammetry method. It was found that shear bands are generated before peak strength and shear band patterns vary during the whole shearing process. Under the same test condition, shear band thickness in the two sands was smaller than that in one type of glass beads even if the materials have almost the same mean particle size. Shear band thickness also decreased with increase of confining pressure regardless of particle shape or size. Local maximum shear strain inside shear band grew approximately linearly with global axial strain from onset of shear band to the end of softening. The growth rate is found related to shear band thickness. The wider shear band, the relatively lower the growth rate. Finally, observed shear band inclination angles were compared with classical Coulomb and Roscoe solutions and different results were found for sands and glass beads.

강소성 유한요소법을 이용한 자동차 판넬 성형공정의 평면 변형해석 (Plane-Strain Analysis of Auto-Body Panel Using the Rigid-Plastic Finite Element Method)

  • 양동열;정완진;송인섭;전기찬;유동진;이정우
    • 대한기계학회논문집
    • /
    • 제15권1호
    • /
    • pp.169-178
    • /
    • 1991
  • 본 연구에서는 평면 변형률 강소성 유한요소법을 이용하여 유한요소 수식화를 유도하고 금형이 해석저인 함수로 묘사되는 드로잉 공정을 해석하고, 금형이 해석적인 함수로 묘사되지 않는 실제적인 자동차 성형품의 드로잉 공정을 해석하여 기존의 결과 와 비교하여 본 방법의 타당성을 검토하였다.

평면변형률 상태 하에서 유한요소해석을 이용한 균열닫힘 거동 예측 및 평가 (Finite Element Analysis of Fatigue Crack Closure under Plane Strain State)

  • 이학주;송지호;강재윤
    • 대한기계학회:학술대회논문집
    • /
    • 대한기계학회 2004년도 추계학술대회
    • /
    • pp.202-207
    • /
    • 2004
  • An elastic-plastic finite element analysis of fatigue crack closure is performed for plane strain conditions. The stabilization behavior of crack opening level and the effect of mesh size on the crack opening stress are investigated. In order to obtain a stabilized crack opening level for plane strain conditions, the crack must be advanced through approximately four times the initial monotonic plastic zone. The crack opening load tends to increase with the decrease of mesh size. The mesh size nearly equal to the theoretical plane strain cyclic plastic zone size may provide reasonable numerical results comparable with experimental crack opening data. The crack opening behavior is influenced by the crack growth increment and discontinuous opening behavior is observed. A procedure to predict the most appropriate mesh size for different stress ratio is suggested. Crack opening loads predicted by the FE analysis based on the procedure suggested resulted in good agreement with experimental ones within the error of 5 %. Effect of the distance behind the crack tip on the crack opening load determined by the ASTM compliance offset method based on the load-displacement relation and by the rotational offset method based on the load-differential displacement relation is investigated. Optimal gage location and method to determine the crack opening load is suggested.

  • PDF