• Title, Summary, Keyword: 임계하중

Search Result 224, Processing Time 0.164 seconds

Critical Loads of Tapered Beck's Columns with Clamped and Spring Supports (일단고정 타단스프링으로 지지된 변단면 Beck 기둥의 임계하중)

  • Kim Suk-Ki;Park Kwang-Kyou;Lee Byoung-Koo
    • Journal of the Computational Structural Engineering Institute of Korea
    • /
    • v.19 no.1
    • /
    • pp.85-92
    • /
    • 2006
  • This paper investigates critical loads of the tapered Beck's columns with clamped and spring supports, subjected to a subtangential follower force. The linearly tapered columns with the solid rectangular cross-section is adopted as the column taper. The differential equation governing free vibrations of such Beck's columns is derived using the Bemoulli-Euler beam theory. Both divergence and flutter critical loads are calculated from the load-frequency curves which are obtained by solving the differential equation. The critical loads are presented as functions of various non-dimensional system parameters: the taper type, the subtangential parameter and the spring stiffness.

Critical Loads of Tapered Cantilever Columns with a Tip Mass (자유단 집중질량을 갖는 변단면 캔틸레버 기둥의 임계하중)

  • Jeong, Jin Seob;Lee, Byoung Koo;Kim, Gwon Sik;Kim, Jong Ung
    • Journal of Korean Society of Steel Construction
    • /
    • v.17 no.6
    • /
    • pp.699-705
    • /
    • 2005
  • This paper investigates critical loads of tapered cantilever columns with a tip mass, subjected to a follower force. The linearly tapered solid rectangular cross-sections are adopted as the column taper. The differential equation governing free vibrations of such columns, also called Beck's columns, is derived using the Bernoulli-Euler beam theory. Both divergence and flutter critical loads are calculated from the load-frequency curves that are obtained by solving the differential equation. The critical loads are presented as functions of various non-dimensional system parameters, namely, the taper type, the subtangential parameter, and the mass ratio.

A study on critical load due to external force influencing on flight characteristics of a small slender body rocket. (가늘고 긴 소형로켓의 비행특성에 영향을 주는 외력에 기인한 임계하중에 관한 연구)

  • Go, Tae-Sig;Na, Seon-Hwa
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • /
    • pp.393-397
    • /
    • 2007
  • The aim of this study is to investigate critical load, which can influence on flight path of a small slender body rocket, due to external forces such as thrust, drag and weight. The critical load was firstly obtained from Euler column equation, and compared with analysis results using Finite Element Method to evaluate the theoretical critical load.

  • PDF

A Safety Analysis on the Structural Rupture of Cylindrical Shell by Finite Difference Method (차분법에 의한 실린더형 쉘구조의 안정성 연구)

  • Kim, Chi-Kyung;Park, Hwa-Yong
    • Journal of the Korea Safety Management and Science
    • /
    • v.13 no.3
    • /
    • pp.37-43
    • /
    • 2011
  • 본 연구에서는 실린더 형 쉘 구조물의 구조적 안정성에 대하여 해석 하였다. 임계하중은 하중을 점차적으로 증가 하여 구조물이 파괴가 발생 할 때의 상태에서 가장 작은 하중을 의미한다. 셀 구조의 안정성을 임계하중의 크기로 기초를 두고 해석 하였다. 실린더 형 쉘의 차분해석은 일차적 원통형 판구조와 같으므로 최근에 많은 연구의 대상이 되어왔다. 차분법은 복잡한 구조물에서도 물론, 다양한 경계조건을 포함하는 문제에 이르기까지 효과적인 수치방법이다. 본 연구에서는 기본 쉘의 지배방정식을 유도하고 차분화 하여 직접적으로 접근하였다. 등분포 하중의 내압을 받고 있는 갇힌 실린더 형 쉘의 처짐 및 응력을 해석 하였다. 수치해석 결과를 해석해와 비교 검토하였으며 안정성에 대하여 임계 하중강도의 범위를 산출하였다.

A Study on Subcritical Crack Growth Parameters in Rock-like Material under Monotonic and Cyclic Loading (단조 및 반복하중 하에서의 모사 암석 시료의 임계하 균열성장 지수에 관한 연구)

  • Ko, Tae Young
    • Tunnel and Underground Space
    • /
    • v.29 no.2
    • /
    • pp.124-134
    • /
    • 2019
  • Subcritical crack growth in rock material can occur under monotonic and cyclic loading. Subcritical crack growth plays an important role in evaluating the long-term stability of structures in rocks. This paper presents the results of studies conducted to determine subcritical crack growth parameters under monotonic and cyclic loading in rock-like material. The constant stress rate method was employed for monotonic loading. The subcritical crack growth parameter of n under cyclic loading was determined by the relation between the rate of crack growth per cycle and stress intensity factor range. The specimens contained pre-existing flaws with 45 and 60 degrees of inclination angle and flaws spacing and continuity were varied to arrange crack growth in shear or tensile manner. The results show that the parameter of n is almost constant regardless of the applied load conditions such as monotonic and cyclic or shear and tension.

Microhardness measurement for a few micron thick TiN thin films (수미크론 두께를 갖는 TiN코팅층의 미소경도 측정법)

  • Jo, Yeong-Rae;Fromm, E.
    • Korean Journal of Materials Research
    • /
    • v.5 no.3
    • /
    • pp.310-315
    • /
    • 1995
  • 기계적으로 연마한 고속도강과 구리 두 종류의 서로 다른 기판상에 dc 마그네트론 스파터법으로 TiN 박막을 성막시켜 코팅층의 비커스 미소경도를 측정하였다. 압입체의 침투깊이와 시험하중과의 관계를 log-log 좌표상에 도시함으로써 기판의 영햐응ㄹ 받지 않고 코팅층만의 경도를 측정할수 있는 최대하중인 임계하중(critical load)을 구할수 있었다. 임계하중을 가했을 때 압입체의 침투깊이와 코팅층 두께간의 비율은 코팅층의 두께에 무관하였고 기판의 경도에 크게 의존하였다.

  • PDF

Critical Loads and Post-Buckling Behaviour of Simply Supported Tapered Columns (단순지지(單純支持) 변단면(變斷面) 기둥의 임계하중(臨界荷重) 및 후좌굴(後挫屈) 거동(擧動))

  • Lee, Byoung Koo;Oh, Sang Jin;Mo, Jeong Man
    • Journal of The Korean Society of Civil Engineers
    • /
    • v.11 no.4
    • /
    • pp.17-26
    • /
    • 1991
  • Numerical methods are developed to obtain the critical loads and to analyze the post-buckling behaviour of the linearly varying tapered columns. The non-dimensional differential equations governing the elastica of post buckled column are derived by third order and solved numerically using the Runge-Kutta method and Regula-Falsi method. Three kinds of cross-sectional shape with simply supported end constraint are applied in unmerical examples. As the numerical results, the equlibrium paths. the typical elastica of post buckled columns and the critical load vs. section ratio curves are presented in figures. Also, the effects of cross-sectional shape factor on critical loads and postbuckling behaviour are presented in tables.

  • PDF

Stability Analysis of Beck's Column with a Tip Mass Restrained by a Spring (스프링으로 지지된 자유단에 집중질량을 갖는 Beck 기둥의 안정성 해석)

  • Li, Guangfan;Oh, Sang-Jin;Kim, Gwon-Sik;Lee, Byoung-Koo
    • Transactions of the Korean Society for Noise and Vibration Engineering
    • /
    • v.15 no.11
    • /
    • pp.1287-1294
    • /
    • 2005
  • The purpose of this paper is to investigate free vibrations and critical loads of the Beck's columns with a tip spring, which carry a tip mass. The ordinary differential equation governing free vibrations of Beck's column subjected to a follower force is derived based on the Bernoulli-Euler beam theory Both the divergence and flutter critical loads are calculated from the load-frequency corves that are obtained by solving the differential equation numerically. The critical loads are presented in the figures as functions of various non-dimensional system parameters such as the subtangential parameter, mass ratio and spring parameter.

Critical Speed Analysis of a 75 Ton Class Liquid Rocket Engine Turbopump due to Load Characteristics (75톤급 액체로켓엔진 터보펌프의 하중 특성에 따른 임계속도 해석)

  • Jeon, Seong-Min;Kwak, Hyun-D.;Hong, Soon-Sam;Kim, Jin-Han
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • /
    • pp.22-29
    • /
    • 2011
  • Critical speed of high thrust liquid rocket engine turbopump is obtained through a rotordynamic analysis and a unloaded turbopump test is peformed for validation of the numerical model. The first critical speed predicted by the numerical analysis is correlated well with the test result for the bearing unloaded rotor condition only considering mass unbalance load. Using the previous rotordynamic model, critical speed variation is estimated as a function of varied bearing stiffness due to pump and turbine radial loads with relative angle difference. From the numerical analysis, it is found that the relative angle difference of pump and turbine radial loads greatly affects the critical speed. However, additional axial load reduces the effect derived from the relative angle difference of radial loads.

  • PDF

Critical Speed Analysis of a 75 Ton Class Liquid Rocket Engine Turbopump due to Load Characteristics (75톤급 액체로켓엔진 터보펌프의 하중 특성에 따른 임계속도 해석)

  • Jeon, Seong-Min;Kwak, Hyun-D.;Hong, Soon-Sam;Kim, Jin-Han
    • Journal of the Korean Society of Propulsion Engineers
    • /
    • v.16 no.4
    • /
    • pp.42-49
    • /
    • 2012
  • Critical speed of high thrust liquid rocket engine turbopump is obtained through a rotordynamic analysis and a unloaded turbopump test is peformed for validation of the numerical model. The first critical speed predicted by the numerical analysis is correlated well with the test result for the bearing unloaded rotor condition only considering mass unbalance load. Using the previous rotordynamic model, critical speed variation is estimated as a function of varied bearing stiffness due to pump and turbine radial loads with relative angle difference. From the numerical analysis, it is found that the relative angle difference of pump and turbine radial loads greatly affects the critical speed. However, additional axial load reduces the effect derived from the relative angle difference of radial loads.