• Title/Summary/Keyword: small school

Search Result 8,303, Processing Time 0.036 seconds

Assessment of Creep Properties of 9Cr Steel Using Small Punch Creep Testing (소형펀치 크리프 시험을 이용한 9Cr강의 크리프 상수 평가)

  • Yun, Gi-Bong;Park, Tae-Gyu;Sim, Sang-Hun;Jeong, Il-Seok
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.25 no.9
    • /
    • pp.1493-1500
    • /
    • 2001
  • Recently small punch creep testing (or miniature disc bend creep test) has received much attention through European collaborative research projects. This method was considered as a substitute for the conventional creep rupture testing by which the residual creep life is measured from the specimen taken out from serviced components of high temperature plants. It would be beneficial if the material creep properties such as power law creep constants as well as the creep rupture life can be measured from the small punch creep test. In this paper a method of assessing creep constants from the small punch creep testing is proposed. Finite element analyses were performed to investigate evolution of stress and strain rate at the weakest locations of the small punch creep specimen. Elastic-plastic-secondary creep analyses were carried out. The estimation equations for creep constants by the small punch creep testing are proposed based on the finite analysis results. Small punch creep tests were also performed with 9Cr steel and the accuracy of the proposed equation was verified by the experimental results.

Improved Security Monitoring and Control Using Analysis of Cyber Attack in Small Businesses (중소기업 유해트래픽 분석을 통한 보안관제 개선 방안)

  • Hong, Jun Suk;Lim, Young Hwan;Park, Won Hyung;Kook, Kwang Ho
    • The Journal of Society for e-Business Studies
    • /
    • v.19 no.4
    • /
    • pp.195-204
    • /
    • 2014
  • Recent, Secure the small and medium-sized enterprises from advanced and intelligence cyber threat, 24 hours of prevention, detection and analysis is essential. Small and Medium Business monitoring center is operated by government financial support to protect and prevent these threats. Currently it provides security to about 900 small and medium-sized enterprises. This paper studies abnormal and attack packets from small and medium-sized businesses[enterprises] which is monitored by Small and Medium Business monitoring center and provides improvement of security control for small and medium-sized enterprises.

Design of Small-Scaled Derailment Simulator for Investigating Bogie Dynamics

  • Eom, Beom-Gyu;Kang, Bu-Byoung;Lee, Hi-Sung
    • International Journal of Railway
    • /
    • v.4 no.2
    • /
    • pp.50-55
    • /
    • 2011
  • The dynamic stability of railway vehicle has long been one of the important issues in railway safety. The dynamic simulator has been used as a tool for investigating the dynamic stability of railway vehicles and wheel/rail interfaces. In particular, small scale simulators have been widely used in laboratory studies instead of full scale roller rigs which can be quite costly and rather inconvenient for testing out the effect of diverse design parameters. But techniques for design of a small scale simulator for the fundamental study about the dynamic characteristics of the wheel-rail systems and the bogie systems have not been well developed in Korea. Therefore, a research on the development of a small scale simulator for investigating bogie dynamics needs to be undertaken. The present paper investigates design of a small-scaled derailment simulator and the design of a small scale bogie. The simulator developed can be used to investigate the effect of diverse parameters such as attack angle, wheelbase and cant on dynamic behavior of the bogie and key dynamic performance parameters such as derailment coefficient and critical speed.