• 제목/요약/키워드: Inner behavior

검색결과 612건 처리시간 0.028초

Theoretical and experimental study on load-carrying capacity of combined members consisted of inner and sleeved tubes

  • Hu, Bo;Gao, Boqing;Zhan, Shulin;Zhang, Cheng
    • Structural Engineering and Mechanics
    • /
    • 제45권1호
    • /
    • pp.129-144
    • /
    • 2013
  • Load-carrying capacity of combined members consisted of inner and sleeved tubes subjected to axial compression was investigated in this paper. Considering the initial bending of the inner tube and perfect elasto-plasticity material model, structural behavior of the sleeved member was analyzed by theoretic deduction, which could be divided into three states: the elastic inner tube contacts the outer sleeved tube, only the inner tube becomes plastic and both the inner and outer sleeved tubes become plastic. Curves between axial compressive loads and lateral displacements of the middle sections of the inner tubes were obtained. Then four sleeved members were analyzed through FEM, and the numerical results were consistent with the theoretic formulas. Finally, experiments of full-scale sleeved members were performed. The results obtained from the theoretical analysis were verified against experimental results. The compressive load-lateral displacement curves from the theoretical analysis and the tests are similar and well indicate the point when the inner tube contacts the sleeved tube. Load-carrying capacity of the inner tube can be improved due to the sleeved tube. This paper provides theoretical basis for application of the sleeved members in reinforcement engineering.

일부 치위생과 학생들의 전공선택동기와 직업가치관에 따른 취업준비행동에 관한 연구 (A study on employment preparation behavior based on motive to select dental hygiene as major and their work value among dental hygiene students)

  • 신선행
    • 한국치위생학회지
    • /
    • 제17권5호
    • /
    • pp.853-864
    • /
    • 2017
  • Objectives: The purpose of the study was to investigate the influence of employment preparation behavior on motive to select dental hygiene as their major, and their work value among dental hygiene students. Methods: A self-reported questionnaire was completed by 444 dental hygiene students in South Korea from November 1 to 30, 2016. To analyze the data, the study used independent t-test, one way ANOVA, Pearson's correlation analysis, and regression analysis among others. Results: There were employment preparation behavior (2.9), major selection motive (3.1), and their work value (3.8) in subject. The higher student's grade is, the better prepared he or she for employment (p<0.001). Inner work value (p<0.01) and outer work value (p<0.05) were higher among females than males. Employment preparation behavior had significant positive effect on personal, social motive to select dental hygiene as their major, and their inner work value. Conclusions: Positive motivation to employment preparation behavior leads to major motive to select major, and their work value. It is necessary to consider study of diversified manners that can be fulfilled for employment preparation behavior.

침식-부식에 의해 감육된 배관의 파손거동에 미치는 감육위치의 영향 (Effect of Local Wall Thinned Location due to Erosion-Corrosion on Fracture Behavior of Pipes)

  • 안석환;석금철;남기우
    • 한국해양공학회지
    • /
    • 제21권1호
    • /
    • pp.51-58
    • /
    • 2007
  • This study on the effects of local wall-thinned location on the fracture behavior of pipes was carried out, and the results were compared with the analytical results. Local wall-thinning for the bending test was machined with various sizes on the outside of pipes, in order to simulate the metal loss, due to erosion/corrosion. In addition, we had carried out FE analysis for the pipes with local wall thinning on the inside, and its results were comparatively studied with that of the outside. Three-dimensional elasto-plastic analyses were able to accurately simulate fracture behaviors of inner or outer wall thinning. Fracture types, obtained from the experiments and analyses, could be classified into ovalization, local buckling and crack initiation, depending on the thinned length and thinned ratio. Based on the results, the fracture behaviors of pipes with the outer wall thinning can be applied to estimate the fracture behaviors of pipes with the inner wall thinning.

표면 효과를 고려한 극박 SS304 스테인리스 강판의 굽힘 거동 분석 (Analysis of Bending Behavior of Ultra-thin SS304 Stainless Steel Sheets Considering the Surface Effect)

  • 정재봉;채준열;정양진;김지훈
    • 소성∙가공
    • /
    • 제29권6호
    • /
    • pp.323-330
    • /
    • 2020
  • The surface region of a sheet metal may have different characteristics from the inner region because the surface region is less restricted than the interior. In addition, the grains on the free surface are less hardened because of surface adsorption of the dislocations, rather than piling up. In the case of bulk or thick sheet metals, this effect is negligible because the fraction of the surface region is much smaller than that of the inner region. However, this surface effect is important in the case of ultra-thin sheet metals. In order to evaluate the surface effect, tensile and bending tests were performed for the SS304 stainless steel with a thickness of 0.39 mm. The bending force predicted using the tensile behavior is higher than the measurement because of the surface effect. To account for the surface effect, the surface layer model was developed by dividing the sheet section into surface and inner layers. The mechanical behaviors of the two regions were calibrated using the tensile and bending properties. The surface layer model reproduced the bending behavior of the ultra-thin sheet metal.

하드 디스크 드라이브 비 동작 충격 시에 내부 파트들의 동 특성에 대한 연구 (A study on dynamic behavior of inner parts with non-operational shock in hard disk drive)

  • 최용호;최종학;임건엽;서준호;박노철
    • 정보저장시스템학회논문집
    • /
    • 제9권2호
    • /
    • pp.32-35
    • /
    • 2013
  • Nowadays, function related to anti-vibration and anti-shock of storage devices is required because of portability. Therefore, many hard disk drive (HDD) studies about external shock and vibration have been performed. Especially, many studies are performed with non-operational shock. Most studies have used the fixed condition between spindle system and base when they wanted to analyze dynamic behavior of inner parts in simulation. But spindle system has actually stiffness and damping coefficient. Maybe difference of value would be happened between fixed condition and spring condition. So, we measured FRF of spindle system to know stiffness and damping coefficient in HDD. And we studied on dynamic behavior of inner parts by using calculated stiffness and damping coefficient. As a result, we confirmed the difference as boundary condition of spindle system.

스트레인 게이지를 이용한 C-type LNG Mock-up 탱크 내조 실 변형 거동 측정 (Measurement of Real Deformation Behavior in C-type Lng Mock-up Tank using Strain Gage)

  • 정원도;김태욱;김정현;이도영;전민성;이제명
    • 한국해양공학회지
    • /
    • 제30권2호
    • /
    • pp.117-124
    • /
    • 2016
  • A C-type LNG mock-up tank was constructed to evaluate the durability of the tank and its structural safety. An experimental strain analysis system equipped with strain gages was designed to investigate the structural behavior of the inner tank at a high hydraulic pressure. In addition, the insulation used in the space between the inner tank and outer tank had a compressive strength and the inner tank thickness of the cylindrical shell and hemisphere was 4.0 mm, which was designed to be thinner than the existing rules. The strains on the inner tank were measured with increasing pressure, and these measurements were compared and analyzed at the strain gage attachment points.

내압을 받는 내/외부 국부 감육 곡관의 파손거동 (Damage Behavior of Elbow Pipe with Inner or Outer Local Wall Thinning under Internal Pressure)

  • 김수영;남기우
    • 동력기계공학회지
    • /
    • 제18권5호
    • /
    • pp.66-73
    • /
    • 2014
  • This study was considered to occur the local wall thinning at elbow which is flowing the steam and high-pressure water of high-temperature. The angle of elbow is ${\Theta}=45^{\circ}$ and $67.545^{\circ}$. The damage behaviors of inner or outer wall thinning elbow under internal pressure were calculated by FEA(finite element analysis). We compared the simulated results by FEA with experimental data. The FEA results are as follows: In the FEA results of three types of wall thinning ratio, the circumferential and longitudinal stresses show the similar values regardless of the angle of elbow, respectively. The circumferential strain was greater at elbow of small angle, but the longitudinal strain was nearly same. The FEM stress of outer wall thinning elbow was slightly higher than that of the inner wall thinning elbow, and strain was also slightly higher. In the experiments, the circumferential strain was increased with the increase in the internal pressure, and increased rapidly on about 0.2% of strain. The longitudinal strain was small. The strain at break was much smaller than 0.2%. In the relation between pressure and eroded ratio, the criteria that can be used safely under operating pressure and design pressure were obtained. The results of FEA were in relatively good agreement with those of the experiment.

Behavior of CFST columns with inner CFRP tubeunder biaxial eccentric loading

  • Li, Guochang;Yang, Zhijain;Lang, Yan;Fang, Chen
    • Steel and Composite Structures
    • /
    • 제22권6호
    • /
    • pp.1487-1505
    • /
    • 2016
  • This paper presents the results of an experimental study on the behavior of a new type of composite FRP-concrete-steel member subjected to bi-axial eccentric loading. This new type of composite member is in the form of concrete-filled square steel tube slender columns with inner CFRP (carbon fiber-reinforced polymer) circular tube, composed of an inner CFRP tube and an outer steel tube with concrete filled in the two tubes. Tests on twenty-six specimens of high strength concrete-filled square steel tube columns with inner CFRP circular tube columns (HCFST-CFRP) were carried out. The parameters changed in the experiments include the slenderness ratio, eccentric ratio, concrete strength, steel ratio and CFRP ratio. The experimental results showed that the failure mode of HCFST-CFRP was similar to that of HCFST, and the specimens failed by local buckling because of the increase of lateral deflection. The steel tube and the CFRP worked together well before failure under bi-axial eccentric loading. Ductility of HCFST-CFRP was better than that of HCFST. The ultimate bearing capacity of test specimen was calculated with simplified formula, which agreed well with test results, and the simplified formula can be used to calculate the bearing capacity of HCFSTF within the parameters of this test.

Axial behavior of square CFST encased seawater sea-sand concrete filled PVC/GFRP tube columns

  • Rong Su;Xian Li;Ziwei Li
    • Steel and Composite Structures
    • /
    • 제47권6호
    • /
    • pp.781-794
    • /
    • 2023
  • In order to directly apply seawater and sea sand in construction without desalination, a type of square concrete-filled steel tube (CFST) encased with prefabricated seawater sea-sand concrete filled Polyvinyl Chloride (PVC)/Glass Fiber Reinforced Polymer (GFRP) tube column was proposed. Twenty short columns were tested under uniaxial loads, and the test parameters included inner tube types, seawater sea-sand concrete replacement ratios, concrete strength, the wrapping area of Carbon Fiber Reinforced Polymer (CFRP) strips and the thickness of GFRP tube. The effects of the parameters on failure modes, loading capacity, ductility and strain responses were discussed. All the tested specimens failed with serious buckling of the steel tubes and fracture of the inner tubes. The specimens had good residual bearing capacity corresponding to 64% to 88.9% of the peak capacity. The inner GFRP tubes and PVC tubes wrapped by CFRP strips provided stronger confinement to the core concrete, and were good choices for the proposed columns. Moreover, an analytical model for the composite column with different inner tube types was proposed.

복층터널 내부슬래브의 연결형식에 관한 수치해석적 연구 (Numerical study on the connection type of inner-slab in double deck tunnel)

  • 이호성;문현구
    • 한국터널지하공간학회 논문집
    • /
    • 제18권5호
    • /
    • pp.441-451
    • /
    • 2016
  • 본 연구에서는 쉴드 TBM에 의한 대심도 복층터널의 계획 시 세그먼트 라이닝의 거동을 주요 구조물인 내부 슬래브의 연결구조 형식에 따라 검토하였다. 복층터널의 내부슬래브와 세그먼트 라이닝 설계 요구조건을 정립하기 위하여 용도에 따라 내부 구조물의 형식을 정의하고, 터널 라이닝과 내부 슬래브의 연결구조를 비교하였다. 그리고 MIDAS Civil 2012 프로그램으로 빔-스프링 모델을 이용하여 수치해석을 수행하였다. 본 연구결과 중간슬래브 및 하부슬래브, 내부슬래브와 세그먼트 라이닝의 연결 형식 그리고 측압계수들은 복층터널 계획시 주요 설계사항임을 확인하였다.