• Title/Summary/Keyword: Internal Loading

Search Result 614, Processing Time 0.029 seconds

Anisotropic continuum damage analysis of thin-walled pressure vessels under cyclic thermo-mechanical loading

  • Surmiri, Azam;Nayebi, Ali;Rokhgireh, Hojjatollah;Varvani-Farahani, Ahmad
    • Structural Engineering and Mechanics
    • /
    • v.75 no.1
    • /
    • pp.101-108
    • /
    • 2020
  • The present study intends to analyze damage in thin-walled steel cylinders undergoing constant internal pressure and thermal cycles through use of anisotropic continuum damage mechanics (CDM) model coupled with nonlinear kinematic hardening rule of Chaboche. Materials damage in each direction was defined based on plastic strain and its direction. Stress and strain distribution over wall-thickness was described based on the CDM model and the return mapping algorithm was employed based on the consistency condition. Plastic zone expansion across the wall thickness of cylinders was noticeably affected with change in internal pressure and temperature gradients. Expansion of plastic zone over wall-thickness at inner and outer surfaces and their boundaries demarking elastic and plastic regions was attributed to the magnitude of damage induced over thermomechanical cycles on the thin-walled samples tested at various pressure stresses.

Effects of Thinning Length on Failure Mode of Local Wall Thinned Pipe (감육 배관의 손상모드에 미치는 감육부 길이의 영향)

  • Kim, Jin-Weon;Park, Chi-Yong;Lee, Sung-Ho;Kang, Tai-Kyung
    • Proceedings of the KSME Conference
    • /
    • 2001.06a
    • /
    • pp.357-362
    • /
    • 2001
  • The pipe fracture tests were performed on 102mm-Sch.80 carbon steel pipe with various local wall thinning shapes, in order to understand failure behavior of thinned pipe. Pipe specimens were subjected to monotonic bending moment, using 4-points loading system, under internally pressurized condition. From the results of experiment, the failure mode, load carrying capacity, and deformability of local wall thinning pipe were investigated. Failure mode of thinned pipe depended on magnitude of internal pressure and thinning length as well as loading direction and thinning depth and angle. The variation in load carrying capacity and deformability of thinned pipe with length of thinned area was determined by stress type appled to thinning region and circumferential thinning angle. Also, the effect of internal pressure on failure behavior was dependent on failure mode of thinned pipe, and it promoted crack occurrence and mitigated local buckling at thinned area.

  • PDF

Nitrogen Removal in the Multi-stage Bed Attached Growth Process of $A^2/O$ System with Interanal Recycle Ratio (다단층 부착성장 공법($A^2/O$향)에서 순환비에 따른 질소제거)

  • 최규철;윤용수;정일현
    • Journal of environmental and Sanitary engineering
    • /
    • v.12 no.3
    • /
    • pp.95-102
    • /
    • 1997
  • The process which can stabilize water quality of treatment and improve nitrogen removal rate under the condition of high organic loading was developed by charging fibrous HBC media to single sludge nitrification-denitrification process. This process was operated easier, minimized the treatment cost, and shortened the retention time. To improve T-N removal rate, a part of nitrifing liquid at aerobic zone was recycled to anoxic zone by approximate internal recycle ratio. The experimental results are as follows ; T-N removal efficiency in the organic volumetric loading 0.14-0.19 kg/COD/m$^{3}$·d was obtained asmaxium of 85% at internal recycle ratio 2.5 and in more ratio than this it was decreased. Organic removal efficiency was about 91% under the overall experimental conditions and not influenced by recycle ratio.

  • PDF

Effect of Local Wall Thinning Defect on the Collapse Moment of Elbow (엘보우의 붕괴모멘트에 미치는 국부 감육결함의 영향)

  • Kim, Jin-Weon;Kim, Tae-Soon;Park, Chi-Yong
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.28 no.4
    • /
    • pp.402-409
    • /
    • 2004
  • The purpose of this study is to investigate the effect of local wall thinning on the collapse of elbow subjected to internal pressure and bending moment. Thus, the nonlinear three-dimensional finite element analyses were performed to obtain the collapse moment of elbow containing various wall thinning defects located at intrados and extrados under two loading modes (closing and opening modes) with internal pressure. From the results of analysis, the effect of wall thinning defect on the global moment-rotation behavior of elbow was discussed, and the dependence of collapse moment of elbow on wall thinning depth, length, and circumferential angle was investigated under different loading mode and defect location.

Manufacturing of High-Performance Double Layered Tube with Corrugated Internal Pattern via the Hydroforming Process (액압 성형을 이용한 내부복합파형 고효율 이중관 제조 기술)

  • Han, S. W.;Kim, D. Y.;Moon, Y. H.
    • Transactions of Materials Processing
    • /
    • v.31 no.3
    • /
    • pp.143-150
    • /
    • 2022
  • The purpose of this study was to investigate an innovative hydroforming process for the cost-effective manufacturing of double layered tube with circumferentially corrugated patterns. Conventional double pipe heat exchanger has relatively poor heat transfer efficiency because of the limited contact area resulting from the concentrically arranged simple cylindrical structure. As a promising alternative to enhance heat transfer efficiency, double layered tube with corrugated internal pattern was considered in this study. To fabricate corrugated inner tube, innovative tube hydroforming system was developed. The customized loading paths were established using the simulated forming pressure and contracting stroke at various bar diameters. Experimentally obtained cross-sectional profiles were analyzed to evaluate the reliability and applicability of the hydroformed tube with various patterns. The results demonstrate that the proposed hydroforming process can be a feasible alternative for manufacturing high-performance double-tube heat exchangers.

Effect of Internal Pressure on the Behavior of Wall Thinned Elbow under In-Plane Bending (In-plane 굽힘 조건에서 감육엘보우 거동에 미치는 내압의 영향)

  • Kim, Jin-Weon;Kim, Tae-Soon;Park, Chi-Yong
    • Proceedings of the KSME Conference
    • /
    • 2004.04a
    • /
    • pp.268-273
    • /
    • 2004
  • This study is conducted to clarify the effect of internal pressure on the deformation and collapse behaviors of wall thinned elbow under in-plane bending moment. Thus the nonlinear three-dmensional finite element analyses were performed to obtain the moment-rotation curve of elbow contatining various wall thinning defects located at intrados and extrados under in-plane bending (closing and opening modes) with internal pressure of $0{\sim}15MPa.$ From the results of analysis, the effect of internal of collapse moment of elbow on the global deformation behavior of wall thinned elbow was discussed, and the dependence of collapse moment of elbow on the magnitude of internal pressure was investigated under different loading mode, defect location, and defect shape.

  • PDF

Impact Analysis of Short Fiber-Reinforced Metal Matrix Composites (단섬유 강화 금속 복합재의 충격 해석에 관한 연구)

  • 안국찬
    • Journal of the Korean Society of Safety
    • /
    • v.9 no.3
    • /
    • pp.3-12
    • /
    • 1994
  • This study employed the Eshelby's equivalent inclusion method incorporated with mean field theory to investigate the Internal stress of short fiber-reinforced metal matrix composites during static loading and the dynamic finite element analysis by using alternative unit cell model to investigate the impact behaviors during the impact loading. Using the 2124 Al-SiC system as an example, the general effects of parameters such as fiber's aspect ratio, content and modulus were examined.

  • PDF

Practical estimation of the plastic collapse limit of curved pipes subjected to complex loading

  • Yan, A.M.;Nguyen, D.H.;Gilles, Ph.
    • Structural Engineering and Mechanics
    • /
    • v.8 no.4
    • /
    • pp.421-438
    • /
    • 1999
  • In this paper a practical limit load estimating procedure is proposed for general pipe-elbow structures subjected to complex loading (in-plane and out-of-plane bending, internal pressure and axial force). The explicit calculating formulae are presented on the basis of theoretical analysis combined with numerical simulation. Von Mises' yield criterion is adopted in both analytical and numerical calculation. The finite element examination shows that the method provides a simple but satisfactory prediction of pipe structures in engineering plastic analysis.

Cooling Test of The HTS Power Cable (초전도케이블 냉각시험)

  • 염한길;고득용;홍용주;김익생;김춘동;김도형
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
    • /
    • 2003.02a
    • /
    • pp.295-297
    • /
    • 2003
  • Cryogenic systems is requirement for the operation of HTS power cables. In general, HTS power cables require temperature below 77K, a temperature that can be achieved from the liquid nitrogen or sub-cooled LN2. HTS power cable is needed for sufficient refrigeration to overcome its low temperature heat loading. This loading typically comes in two forms : (1) heat leaks from the surroundings and (2) internal heat generation. This paper is a explanation for the cooling test of 10m HTS power cable.

  • PDF

Evaluation of Installation and Arrangement Effects of Internal Ring Stiffener for Tubular K-joints with Axially Loaded Braces (지부재에 축하중을 받는 K형 관이음부의 내부 환보강재의 설치 및 배치효과 평가)

  • Cho, Hyun-Man;Ryu, Yeon-Sun;Lim, Dong-Joo
    • Journal of the Computational Structural Engineering Institute of Korea
    • /
    • v.24 no.3
    • /
    • pp.267-274
    • /
    • 2011
  • The effect of internal ring stiffeners is numerically evaluated for reinforcement of tubular K-joints. Finite element analyses are performed to compute stress of un-stiffened and ring-stiffened K-joints subjected to axial loading. The influence of loading condition and geometrical parameters of ring stiffener on joint behavior is assessed to determine the installation effect of single and double ring stiffeners. The arrangement effect of ring stiffener are evaluated using quantitative analysis compared single ring with double ring stiffeners. Based on the numerical results, practical size of ring stiffener is proposed for design of tubular K-joints.