• Title/Summary/Keyword: Opening Load

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An Influence of Rectangular Openings on the Structural Behavior in Reinforced Concrete Deep Beams (철근콘크리트 깊은 보의 구조적 거동에 대한 장방형 개구부의 영향)

  • Yang Keun-Hyeok;Chung Heon-Soo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.05a
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    • pp.395-398
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    • 2005
  • To understand an influence of rectangular openings on the structural behavior in reinforced concrete deep beams, results of 52 specimens were analyzed. The structural behavior such as load-deflection relationship, load-maximum crack width relationship, and maximum strength was significantly affected by inclination of concrete strut beneath opening.

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Implementation of the Dynamic Simulator for Predicting Operating Characteristics of Three-Phase Induction Motors (유도전동기의 운전 특성 예측을 위한 동적 시뮬레이터 구성)

  • Pyon, H.S.;Hahn, S.C.
    • Proceedings of the KIEE Conference
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    • 2000.07b
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    • pp.906-908
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    • 2000
  • This paper presents dynamic modeling and simulation of induction motors. Equivalent circuit parameters measured by do test, no-load test and locked-rotor test were used as the input data for computer simulation. Operating characteristics of an induction motor were predicted by Matlab/simulink when changing load torque, opening and reclosing of phase a of the stator and three-phase fault at machine terminals.

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Validation of 3D crack propagation in plain concrete -Part I: Experimental investigation - the PCT3D test

  • Feist, C.;Hofstetter, G.
    • Computers and Concrete
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    • v.4 no.1
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    • pp.49-66
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    • 2007
  • The objective of this paper is to provide experimental data on the propagation of curved crack-surfaces and the respective load-displacement diagrams for the validation of numerical models for cracking of concrete, subjected to three-dimensional stress states. To this end beam-shaped specimens are subjected to combined bending and torsional loading, leading to the formation of a spatially curved crack-surface. The experimental data contain the evolution of the load and of the strains at selected points in terms of the crack mouth opening displacement and the propagation of the crack surface.

Closed-Form Plastic Collapse Loads of Pipe Bends Under Combined Pressure and In-Plane Bending (압력과 모멘트의 복합하중을 받는 곡관의 소성 붕괴하중 예측식 개발)

  • Oh Chang-Sik;Kim Yun-Jae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.30 no.8 s.251
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    • pp.1008-1015
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    • 2006
  • Based on three-dimensional (3-D) FE limit analyses, this paper provides plastic limit, collapse and instability load solutions for pipe bends under combined pressure and in-plane bending. The plastic limit loads are determined from FE limit analyses based on elastic-perfectly plastic materials using the small geometry change option, and the FE limit analyses using the large geometry change option provide plastic collapse loads (using the twice-elastic-slope method) and instability loads. For the bending mode, both closing bending and opening bending are considered, and a wide range of parameters related to the bend geometry is considered. Based on the FE results, closed-form approximations of plastic limit and collapse load solutions for pipe bends under combined pressure and bending are proposed.

Properties of the Load-Sensing Hydraulic System from a Viewpoint of Control (제어관점에서의 부하감지형 유압시스템의 특성)

  • 김성동
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.3
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    • pp.738-750
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    • 1994
  • The load-sensing hydraulic system which was developed to improve energy efficiency of conventional hydraulic systems has its own properties. The instability of system responses, linearity of a servo valve, robustness for variation of external load, and dynamic interference between hydraulic motors are such properties which have much to do with control properties of the system. The load-sensing hydraulic system has instability tendancy because the load-sensing mechanism makes a positive feedback loop between the motor part and the pump part. A flow property of the servo valve can be said to be linear because the flow through the valve has nothing to do with a load pressure and the flow is strictly proportional to a valve opening which is adjusted by a valve command signal. The resultant control property can be said to be robust because the steady-state control performance is independent to the load actuated on the motor shaft. In the case when one pump simultaneously drives more than two hydraulic motors, the pump outlet pressure is determined by a hydraulic motor of the largest load pressure among all of the hydraulic motors, and, thus, the other motors are dominated by the largest load pressure. That is, the other motors can be said to be interfered by the motor of the largest load pressure.

Comparison of Gap Pressure in Opening Wedge High Tibial Osteotomy versus Compressive Strength of Allogenous Wedge Bone Blocks (경골 근위부 개방 절골술 시 개방부 압력과 동종 쐐기 골편의 최대압축하중 비교)

  • Yoon, Kyoung Ho;Kim, Jung Suk;Kwon, Yoo Beom;Kim, Eung Ju;Lee, Myeong-Kyu;Kim, Sang-Gyun
    • Journal of the Korean Orthopaedic Association
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    • v.55 no.2
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    • pp.127-134
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    • 2020
  • Purpose: The aims of this study were (1) to investigate the relationship between the characteristics of allogenic bone block and the compressive strength of an allogenic bone block measured by biomechanical experiments, and (2) to compare the maximum pressure load of allogenic bone block with the gap pressure measured at the high tibial opening osteotomy. Materials and Methods: Ten patients who provided informed consent for gap pressure measurements during opening wedge high tibial osteotomy (OWHTO) were included. The gap pressures were measured at 1 mm intervals while opening the osteotomy site from 8 mm to 14 mm. Seventeen U-shaped allogenous wedge bone blocks were made from the femur, tibia, and humerus. The height, width, cross-sectional area, and cortex thickness of the bone blocks were measured, along with the maximum compressive load just before breakage. The relationship between these characteristics and the maximum pressure load of the bone blocks was evaluated. The gap pressures measured in OWHTO were compared with the maximum pressure loads of the allogenous wedge bone blocks to evaluate the possibility of inserting allogenous wedge bone blocks into the osteotomy site without a distractor in OWHTO. Results: The OWHTO gap pressure increased with increasing osteotomy site opening. The mean gap pressure, which occurred at a 14-mm opening, was 282±93 N; the maximum pressure was 427 N. The maximum pressure load of the allografts was 13,379±6,469 N (minimum, 5,868; maximum, 29,130 N) and was correlated significantly with the cortical bone thickness (correlation coefficient=0.693, p=0.002) and cross-sectional area (correlation coefficient=0.826, p<0.001). Depending on the sterilization method, the maximum pressure loads for the bone blocks were 13,406±5,928 N for freeze-dried and 13,348±7,449 N for fresh frozen. The maximum compressive load of the allogenous wedge bone blocks was 13.7-times greater than that in OWHTO opened to 14 mm (5,868 N vs. 427 N). Conclusion: The compressive strength of allogenous wedge bone blocks was sufficiently greater than the gap pressure in OWHTO. Therefore, allogenous wedge bone blocks can be inserted safely into the osteotomy site without a distractor.

Reliability Analysis of Access Door Opening Force Measured with a Digital Force Gauge of a Pressurized Smoke Control Zone and Presentation of Optimum Conditions for the Opening Force (디지털 측정기로 측정된 급기가압 제연구역의 출입문 개방력에 대한 신뢰성 분석 및 최적 조건 제시)

  • Lee, Jae-Ou;Choi, Chung-Seog
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.1
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    • pp.468-473
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    • 2016
  • The aim of this study was to measure the opening force of an access door of a pressurized smoke control zone and verify the reliability of the opening force. For the access door opening force, the opening load of the access door was measured before and after pressurized air had entered the smoke control zone. The reliability of the measured values was verified using the Anderson Darling's statistical analysis method of the Minitab Program. Because the analyzed P values were greater than 0.05 except for some floors before and after the operation of the smoke control equipment, the opening force was found to have 95% reliability. The normal distribution of the measured values showed no relationship with the operation of the smoke control equipment and the precision of the force gauge was believed to be reliable. The major factors for the optimal design of the pressurized smoke control equipment include the precision and reliability of the force gauge, the correct posture of the measuring person, and the same conditions for access doors. Therefore, a digital force gauge is believed to be suitable for measuring the opening force of the access door of a pressurized smoke control zone. In addition, standardization of the posture of a measuring person, the setup of the initial opening force of an access door, etc., are major variables for effective measurements of the door opening force of an access door.

In-Plane Buckling Analysis of Asymmetric Curved Beam Using DQM (미분구적법(DQM)을 이용한 비대칭 곡선보의 내평면 좌굴해석)

  • Kang, Ki-Jun;Park, Cha-Sik
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.10
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    • pp.4706-4712
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    • 2013
  • One of the efficient procedures for the solution of partial differential equations is the method of differential quadrature. This method has been applied to a large number of cases to circumvent the difficulties of programming complex algorithms for the computer, as well as excessive use of storage due to conditions of complex geometry and loading. Under in-plane uniform distributed load, the buckling of asymmetric curved beam with varying cross section is analyzed by using differential quadrature method (DQM). Critical load due to diverse cross section variation and opening angle is calculated. Analysis result of DQM is compared with the result of exact analytic solution. As DQM is used with small grid points, exact analysis result is shown. New result according to diverse cross section variation is also suggested.

Bus Power Quality Index and Cost based on Load-Voltage Characteristics (부하의 전압특성을 고려한 모선별 전력품질 지표 및 가격 산정기법)

  • Lee, Geun-Joon;Heydt, G.T.
    • Proceedings of the KIEE Conference
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    • 2002.11b
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    • pp.9-14
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    • 2002
  • In front of the opening of electric distribution market in 2004. it is indispensable to have a proper estimation of power quality index and power quality cost calculation mechanism are indispensable to stabilize highly industrialized society and to vitalize the investment for electric power system. However, there were not enough measures to reflect the voltage characteristics such as voltage sags and interruptions which make electric load in unstable operation. This paper suggests power quality index(LDI) and power quality cost(LDC) which translate various kinds of voltage records into load drop index and cost based on aggregated load CBEMA curve. A sample calculation result shows that this method can produces the acceptable power quality index and costs for utilities and customers requirements.

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A Study on the Correlation between Outdoor Air and Outlet Air Temperature in a Fresh Air Load Reduction System by Using Geothermal Energy (지열을 이용한 외기부하저감시스템의 외기온도와 출구온도의 상관관계 분석)

  • Son, Won-Tug;Park, Kyung-Soon
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.22 no.9
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    • pp.620-627
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    • 2010
  • This paper presents a feasibility study of a fresh air load reduction system by using an underground double floor space. The fresh air is introduced into the double slab space and passes through the opening bored into the footing beam. The air is cooled by the heat exchange with the inside surface of the double slab space in summer, and heated in winter. This system not only reduces sensible heat load of the fresh air by heat exchange with earth but also reduces latent heat load of the fresh air by ad/de-sorption of underground double slab concrete. In this paper, we investigated the correlation between outdoor air temperature and outlet air temperature in the system. In conclusion, from the results of the high correlation we proposed a equation of regression for the outlet air temperature in the system by using linear regression analysis.