• Title/Summary/Keyword: 상수관

Search Result 327, Processing Time 0.034 seconds

A Study on the Brazier Effect of Laminated Plate Structures Having Different Material Constants for Each Element (재료상수가 상이한 요소로 이루어진 적층평판형구조물의 Brazier효과에 관한 연구)

  • 김재열;한상을;권택진
    • Computational Structural Engineering
    • /
    • v.9 no.3
    • /
    • pp.199-207
    • /
    • 1996

  • When an initially straight thin cylinder is bent, there is a tendency for the cross section to flatten. This phenomenon was investigated by L.G. Brazier in 1927 and is called "Brazier Effect" or "Brazier Theory". The main characteristic is the reduction of carrying capacity due to the decrease of bending stiffness by shortening of thickness with the increase of external load. And the relationship of curvature-bending moment becomes a soft spring type as shown in Fig.2. In this paper, the Brazier theory on plate type structures is investigated from the following view points : (1) What is the Brazier effect? (2) the reason of the occurrence of the Brazier effect in plate type structures by using beam model and (3) factors which cause the brazier effect.

  • PDF

Modeling of the Failure Rates and Estimation of the Economical Replacement Time of Water Mains Based on an Individual Pipe Identification Method (개별관로 정의 방법을 이용한 상수관로 파손율 모형화 및 경제적 교체시기의 산정)

  • Park, Su-Wan;Lee, Hyeong-Seok;Bae, Cheol-Ho;Kim, Kyu-Lee
    • Journal of Korea Water Resources Association
    • /
    • v.42 no.7
    • /
    • pp.525-535
    • /
    • 2009

  • In this paper a heuristic method for identifying individual pipes in water pipe networks to determine specific sections of the pipes that need to be replaced due to deterioration. An appropriate minimum pipe length is determined by selecting the pipe length that has the greatest variance of the average cumulative break number slopes among the various pipe lengths used. As a result, the minimum pipe length for the case study water network is determined as 4 m and a total of 39 individual pipe IDs are obtained. The economically optimal replacement times of the individual pipe IDs are estimated by using the threshold break rate of an individual pipe ID and the pipe break trends models for which the General Pipe Break Prediction Model(Park and Loganathan, 2002) that can incorporate the linear, exponential, and in-between of the linear and exponetial failure trends and the ROCOFs based on the modified time scale(Park et al., 2007) are used. The maximum log-likelihoods of the log-linear ROCOF and Weibull ROCOF estimated for the break data of a pipe are compared and the ROCOF that has a greater likelihood is selected for the pipe of interest. The effects of the social costs of a pipe break on the optimal replacement time are also discussed.

  • https://doi.org/10.3741/JKWRA.2009.42.7.525 인용 PDF KSCI