• Title/Summary/Keyword: Elastic Support

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Free Vibrations of Tapered Cantilever-Type Beams with Tip Mass at the Free End (자유단에 집중질량을 갖는 캔틸레버형 변단면 보의 자유진동)

  • Oh, Sang-Jin;Lee, Jae-Young;Park, Kwang-Kyou;Mo, Jeong-Man
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.11b
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    • pp.965-970
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    • 2002
  • The purpose of this paper is to investigate the free vibration characteristics of tapered beams with general boundary condition(translational and rotational elastic support) at one end and carrying a tip mass with translational elastic support at the other end. The beam model is based on the classical Bernoulli-Euler beam theory which neglects the effects of rotatory inertia and shear deformation. The governing differential equation for the free vibrations of linearly tapered beams is solved numerically using the corresponding boundary conditions. Numerical results are compared with existing solutions by other methods for cases in which they are available. The lowest four natural frequencies are calculated over a wide range of section ratio, dimensionless spring constant and mass ratio.

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EHL Analysis of Connecting Rod Bearings Using Mass-Conserving Boundary Condition (유량 보존 경계 조건을 적용한 커넥팅 로드 베어링의 EHL 해석)

  • 김병직;김경웅
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 1998.04a
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    • pp.212-217
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    • 1998
  • Reynolds equation, which describes behavior of fluid film in journal bearing, basically satisfies mass conservation. But, boundary conditions usually used with this equation, e.g. half Sommerfeld or Reynolds boundary conditions, cannot fulfill this natural law of conservation. In the case of connecting rod bearing, where applied load is dynamic and its magnitude is relatively large, such unrealistic boundary conditions have serious influence on calculation results, especially on lubricant flow rate or power dissipation which are important parameters in thermal analysis. Another important factor in the analysis of connecting rod bearing is elastic deformation of bearing support structure which is relatively flexible. In this paper, EHL analysis of connecting rod beating is performed using mass-conserving boundary condition. Elastic deformation of bearing support structure and application of mass-conserving boundary condition have significant effects on the performances of connecting rod bearing.

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Free Vibrations of Tapered Beams with General Boundary Condition at One End and Mass at the Other End (일단은 일반적인 지지조건을 갖고 타단은 집중질량을 갖는 변단면 보의 자유진동)

  • 오상진;이병구;이태은
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2001.10a
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    • pp.493-500
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    • 2001
  • The purpose of this paper is to investigate the natural frequencies and mode shapes of tapered beams with general boundary condition(translational and rotational elastic support) at one end and carrying a tip mass with translational elastic support at the other end. The beam model is based on the classical Bernoulli-Euler beam theory which neglects the effects of rotatory inertia and shear deformation. The governing differential equation for the free vibrations of linearly tapered beams is solved numerically using the corresponding boundary conditions. Numerical results are compared with existing solutions by other methods for cases in which they are available. The lowest three natural frequencies and the corresponding mode shapes are calculated over a wide range of section ratio, dimensionless spring constant, and mass ratio.

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Stability of Cantilever-Type Columns under Nonconservative Load (비보존력이 작용하는 캔틸레버형 기둥의 안정성)

  • 오상진;이병구;최규문
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2002.10a
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    • pp.244-251
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    • 2002
  • The purpose of this paper is to investigate the stability of tapered columns with general boundary condition(translational and rotational elastic support) at one end and carrying a tip mass of rotatory inertia with translational elastic support at the other end. The column model is based on the classical Bernoulli-Euler beam theory which neglects the effects of rotatory inertia and shear deformation. The governing differential equation for the free vibrations of linearly tapered columns subjected to a subtangential follower force is solved numerically using the corresponding boundary conditions. And the bisection method is used to calculate the critical divergence/flutter load. After having verified the results of the present study, the frequency and critical divergence/flutter load are presented as functions of various nondimensional system parameters.

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Elastic distortional buckling of overhanging beams

  • Bradford, M.A.
    • Structural Engineering and Mechanics
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    • v.4 no.1
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    • pp.37-47
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    • 1996
  • The paper considers the elastic distortional buckling of overhanging beams, which consist of an internal segment with a cantilevered segment continuous over an internal support. The beams were considered loaded by a concentrated load at the cantilever tip, and the beams were either partially restrained or laterally restrained over the internal support. An efficient line-type finite element developed previously by the author was modified to incorporate loading remote from the shear centre, as well as to allow for lateral buckling without distortion. Buckling loads were obtained for a range of geometry when the load was placed on the top flange, at the shear centre or on the bottom flange. Buckling mode shapes were also obtained, and conclusions drawn regarding the influence of distortion on the overall buckling load.

Design and Evaluation Security Control Iconology for Big Data Processing (빅데이터 처리를 위한 보안관제 시각화 구현과 평가)

  • Jeon, Sang June;Yun, Seong Yul;Kim, Jeong Ho
    • Journal of Platform Technology
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    • v.8 no.4
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    • pp.38-46
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    • 2020
  • This study describes how to build a security control system using an open source big data solution so that private companies can build an overall security control infrastructure. In particular, the infrastructure was built using the Elastic Stack, one of the free open source big data analysis solutions, as a way to shorten the cost and development time when building a security control system. A comparative experiment was conducted. In addition, as a result of comparing and analyzing the functions, convenience, service and technical support of the two solution, it was found that the Elastic Stack has advantages in the security control of Big Data in terms of community and open solution. Using the Elastic Stack, security logs were collected, analyzed, and visualized step by step to create a dashboard, input large logs, and measure the search speed. Through this, we discovered the possibility of the Elastic Stack as a big data analysis solution that could replace Splunk.

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Comparison of the Upper and Lower Trapezius and Serratus Anterior during Push-up Plus Exercise with and without an Elastic Shoulder Band

  • Kim, Kyeong-Jin;Woo, Hye-Jin;Hong, Yu-Jeong;Hwang, Young-In
    • Journal of the Korean Society of Physical Medicine
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    • v.13 no.3
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    • pp.75-80
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    • 2018
  • PURPOSE: Scapular stability is very important to arm function during activities of daily living. The push-up plus exercise is commonly used to stabilize the shoulder muscles. In the present study, we designed an elastic shoulder band (ESB) that could be used with the push-up plus exercise and studied muscle activities of the serratus anterior (SA) and the lower and the upper trapezius (LT and UT) on stable and unstable support. METHODS: Fifteen healthy people participated in this study. Three muscles were investigated using surface EMG with and without the ESB on stable and unstable support. All subjects performed each trial three times for 7 seconds per set and rested for 30 seconds. Repeated one-way ANOVA was used for statistical analyses. RESULTS: The EMG activity of the SA was significantly different during the push-up plus exercise on stable support with the ESB compared with that on unstable support without the ESB (p<.05). However, there were no differences in the activities of UT and LT on stable and unstable support (p>.05). CONCLUSION: The ESB was effective for the activity of SA during the push-up plus exercise on stable support; therefore, it has the potential for use by people during push-up plus exercises. However, further studies are required to investigate the rehabilitation tools for patients with shoulder instability.

Immediate Constituent and Technics of Corsetry in the 20C (20세기 코르세트리의 구성 및 제작기법)

  • 전혜정;김지연
    • The Research Journal of the Costume Culture
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    • v.11 no.4
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    • pp.562-577
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    • 2003
  • The object of my research is to inquiry into the immediate constituent and techniques of underwear after looking into basic theory of underwear, techniques by materials classified according to the matter of elasticity, and studying flat pattern and draping which are basis of corset and brassiere structure focusing on corsetry among underwears and production techniques. Various papers are referenced for theoretical study and the elements and techniques of underwear are analyzed based on photographical materials. This paper concludes as follows. To make the flat pattern of corset and brassiere fit to the body tightly, design dart two times without any space and draw smaller than the body. To support the breast sufficiently, move the side seam 1¼″ to the front panel and the seam should pass the apex in all occasions. For draping, dart should be added into short of elasticity materials in the past but dart is no use these days since the material today is extremely elastic. It is possible now to show the body line with only the seam or a pattern. In a case of elastic material, set the elastic direction to the grain line and have a draping as pulling from the center to the out side. As production technic, for an hem, put a zigzag stitch in elastic materials with a 10-20% short elastic band, pulling the band. Then make 3/16″-1/4″ short inseam.

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Dynamic Analysis of Constrained Mechanical System Moving on a Flexible Beam Structure(I) : General Approach (유연한 보 구조물 위를 이동하는 구속 기계계의 동력학 해석(I) : 일반적인 접근법)

  • Park, Chan-Jong;Park, Tae-Won
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.11
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    • pp.165-175
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    • 2000
  • In recent years, it becomes a very important issue to consider the mechanical systems such as high-speed vehicles and railway trains moving on elastic beam structures. In this paper, a general approach, which can predict the dynamic behavior of constrained mechanical system and elastic beam structure, is proposed. Also, various supporting conditions of a foundation support are considered for the elastic beam structures. The elastic structure is assumed to be a nonuniform and linear Bernoulli-Euler beam with proportional damping effect. Combined Differential-Algebraic Equations of motion are derived using multibody dynamics theory and Finite Element Method. The proposed equations of motion can be solved numerically using generalizd coordinate partitioning method and Predictor-Corrector algorithm, which is an implicit multi-step integration method.

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