• Title/Summary/Keyword: Block loading

Search Result 214, Processing Time 0.024 seconds

Crack Growth Behavior of Tensile Overload for Small Load Amplitude at High-Low Block Stress Ratio (고-저블럭 응력비에서 하중진폭이 작은 인장과대 하중의 균열성장 거동)

  • 김엽래
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
    • /
    • 1997.10a
    • /
    • pp.120-126
    • /
    • 1997
  • This paper examines the crack growth behavior of 7075-T651 aluminum alloy under high-low block loading condition. The cantilever beam type specimen with a chevron notch is used in this study. The crack growth and closure are investgated by compliance method. The applied initial stress ratios are R=-0.5, R=0.0 and R=0.25 Crack length($\alpha$), effective stress intensity factor range(ΔKeff), ratio of effective stress intensity factor range(U) and crack growth rate(d$\alpha$/dN) etc. are inspected fracture mechanics estimate.

  • PDF

Ductility enhancement of reinforced concrete thin walls

  • Kim, Jang Hoon
    • Computers and Concrete
    • /
    • v.2 no.2
    • /
    • pp.111-123
    • /
    • 2005
  • The ductility of reinforced concrete bearing walls subjected to high axial loading and moment can be enhanced by improving the deformability of the compression zone or by reducing the neutral axis depth. The current state-of-the-art procedure evaluating the confinement effect prompts a consideration of the spaces between the transverse and longitudinal reinforcing bars, and a provision of tie bars. At the same time, consideration must also be given to the thickness of the walls. However, such considerations indicate that the confinement effect cannot be expected with the current practice of detailing wall ends in Korea. As an alternative, a comprehensive method for dimensioning boundary elements is proposed so that the entire section of a boundary element can stay within the compression zone when the full flexural strength of the wall is developed. In this comprehensive method, the once predominant code approach for determining the compression zone has been advanced by considering the rectangular stress block parameters varying with the extreme compression fiber strain. Moreover, the size of boundary elements can also be determined in relation to the architectural requirement.

Measurement of Surface Crack Length Using Image Processing Technology (영상처리기법을 이용한 표면균열길이 측정)

  • Nahm, Seung-Hoon;Kim, Yong-Il;Kim, Si-Cheon;Ryu, Dae-Hyun
    • Proceedings of the KSME Conference
    • /
    • 2001.06a
    • /
    • pp.96-101
    • /
    • 2001
  • The development of a new experimental method is required to easily observe the growth behavior of fatigue cracks. To satisfy the requirement, an image processing technique was introduced to fatigue testing. The length of surface fatigue crack could be successfully measured by the image processing system. At first, the image data of cracks were stored into the computer while the cyclic loading was interrupted. After testing, crack length was determined using image processing software which was developed by ourselves. Block matching method was applied to the detection of surface fatigue cracks. By comparing the data measured by image processing system with the data measured by manual measurement with a microscope, the effectiveness of the image processing system was established. If the proposed method is used to monitor and observe the crack growth behavior automatically, the time and efforts for fatigue test could be dramatically reduced.

  • PDF

Study on Analysis Method for Welding Deformation of curved Block - Specimen test and Verification (곡 블록 용접변형 해석법에 관한 연구 - 시험편 테스트 및 검증)

  • Lee, Myeong-Su;Jang, Gyeong-Bok;Park, Jung-Gu;Yang, Jin-Hyeok;Gang, Seong-Su
    • Proceedings of the KWS Conference
    • /
    • 2005.11a
    • /
    • pp.17-19
    • /
    • 2005
  • To achieve high productivity of assembly hull blocks, it is important to predict welding deformations accurately and to apply these data to the production planning. In the deformation analysis of hull block, simplified methods (elastic analysis) such as inherent method, equivalent loading method and local & global approach are usually used instead of thermal-elastic-plastic analysis because of calculating time and cost. To be much more practical, these simplified methods should consider gravity effect of plate and contact condition between the plate and the positioning jig. In this research, using finite element method, practical predicting method for the welding deformation of the curved hull blocks with considering welding sequence, gravity effect and contact condition is proposed.

  • PDF

Robust Design of Engine Head Gasket (엔진 헤드 개스킷 강건 설계)

  • Lee, Seungwoo;Yang, Chulho
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.24 no.4
    • /
    • pp.416-424
    • /
    • 2016
  • A robust design of head gasket is pursued by using FEA model of engine assembly. Engine assembly model consists of cylinder head, block, gasket, and head bolt is constructed to understand a complex behavior of this engine compound. Thermal loading is performed on the assembled engine cylinder and block to obtain temperature field. Firing load is added to the results of heat transfer analysis to simulate the engine operation condition. Temperature filed results from heat transfer analysis are mapped into the structural mesh. Contact pressure distribution along the bead has been monitored for the engine operation condition. Based on the results obtained from the analysis, Taguchi method has been adopted for a robust design process of head gasket. Among the control factors, bolt size affects most robustness of head gasket sealing.

A new approach to calculations of the expected energy and reliability indices in the generations system (발전시스템의 발전에너지기대치 및 신뢰도 계산에 관한 연구)

  • 박영문;서보혁;박준호
    • 전기의세계
    • /
    • v.30 no.2
    • /
    • pp.112-118
    • /
    • 1981
  • This paper derives two new algorithms to calculate the expected energy generated and the reliability indices of a generating system when the loading order of the generating units and the load data of the system are given. These algorithms use the probabilistic simulation model considering the two-block system, and can be easily extended to the three or more block system if necesssary. Suggested model I is a more improved algorithm from the conventional ones, in which the load duration curve is used as is in any other conventional algorithms. And model II, by using the newly developed " ENERGY CURVE", remarkably saves the computing time with reducing the computational errors. Case studies were carried out for the actual load data of Korea Electric Company.c Company.

  • PDF

Analysis of the shear failure process of masonry by means of a meso-scopic mechanical modeling approach

  • Wang, Shuhong;Tang, Chun'an;Jia, Peng
    • Structural Engineering and Mechanics
    • /
    • v.24 no.2
    • /
    • pp.181-194
    • /
    • 2006
  • The masonry is a complex heterogeneous material and its shear deformation and fracture is associated with very complicated progressive failures in masonry structure, and is investigated in this paper using a mesoscopic mechanical modelling, Considering the heterogeneity of masonry material, based on the damage mechanics and elastic-brittle theory, the newly developed Material Failure Process Analysis (MFPA) system was brought out to simulate the cracking process of masonry, which was considered as a three-phase composite of the block phase, the mortar phase and the block-mortar interfaces. The crack propagation processes simulated with this model shows good agreement with those of experimental observations by other researchers. This finding indicates that the shear fracture of masonry observed at the macroscopic level is predominantly caused by tensile damage at the mesoscopic level. Some brittle materials are so weak in tension relative to shear that tensile rather than shear fractures are generated in pure shear loading.

A Study for Rationalization of Lifting Lug Design of Ship Block (선박블록 탑재용 러그구조의 설계합리화를 위한 연구)

  • 함주혁
    • Journal of Ocean Engineering and Technology
    • /
    • v.11 no.4
    • /
    • pp.249-261
    • /
    • 1997
  • A basic study on the lifting lug design has performed through the rational and systematic process. In order to evaluate the proper design-load distribution around lug eye investigation of contact force between lifting lug and shackle pin is performed using non-linear parametric analysis idealized by gap element models. Gap element modeling and nonlinear analysis procedures are illustrated and discussed based on MSC/NASTRAN. Some analysis and design guides are suggested through the consideration of several important effects such as stress distribution pattern, circumferential contact force distribution along the lug eye face, loading share rate between lug main plate and doubler, effect of loading direction, relation between applied force and deflection and size effect of shackle pin radius. Additionally optimum design studies are performed and general trends according to the variation of design parameters are suggested.

  • PDF

Analysis of Correction of Welding Deformation of Stiffened Plate by Heating Using Equivalent Loading Method based on Inherent Strain (고유변형도 기반 등가하중법에 의한 보강판의 가열 교정 해석)

  • 송하철;류현수;장창두
    • Journal of the Society of Naval Architects of Korea
    • /
    • v.41 no.4
    • /
    • pp.85-91
    • /
    • 2004
  • The objective of the present paper is to develop an analysis method for the correction of welding deformation of stiffened plate by line heating. In this paper, the equivalent loading method, based on the inherent strain theory, was used to analyze the heat-straightening of a stiffened plate. Equivalent loads were obtained by integrating the inherent strains which were determined from the highest temperature and the degree of restraint. Finally, the obtained equivalent loads were imposed, as applied loads, on the elastic analysis for the prediction of correction of welding deformation in stiffened plate. The proposed method is expected as a basic study in heat-straightening analysis of welding deformation in large scale block.