• 제목/요약/키워드: miner's rule

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적층제조 공법이 적용된 소형 항공 플랫폼용 슬롯 배열 초고주파 안테나의 진동피로수명평가에 대한 연구 (Vibration Fatigue Life for Slot Array RF Antenna Applied to Small Aviation Platform)

  • 김기승;김효태;최혜윤;정화영
    • 한국기계가공학회지
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    • 제21권1호
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    • pp.73-80
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    • 2022
  • Sensors are applied to small aviation platforms for various purposes. Radio frequency (RF) antennas, which are representative sensors, are available in many forms but require the application of slot array RF antennas to ensure high performance and designation. Slot RF array antennas are applied to dip brazing techniques, but the yield and production time are determined by the proficiency of production personnel in a labor-intensive form. Unmanned aerial vehicles or drones, which are representative small aviation platforms, are continuously exposed to various random vibrations because propellers and multiple power sources are used in them. In this study, the fatigue life of slot array RF antennas applied with additive manufacturing was evaluated through the cumulative damage method (Miner's rule) in a vibration environment with a small aviation platform. For the evaluation, an S N curve obtained from a fatigue strength test was used.

복합유성기어의 강도 및 내구성 해석 (Strength and Durability Analysis of the Double Planetary Gears)

  • 한성길;신유인;윤찬헌;송철기
    • 한국기계가공학회지
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    • 제13권5호
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    • pp.28-34
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    • 2014
  • A planetary gear train is more compact and endures greater amounts of transmission power compared to other gear systems. Although planetary gear systems operate in small volumes, they are capable of very high efficiency due to the compact combination of their gears in the planetary gear system. They also have outstanding efficiency of only 3% for power transmission, tantamount to the power loss that occurs in each of the shift stages. Given these advantages, planetary gear systems are used in the driving systems of, which are widely used in automobile transmissions, machine tools, semiconductor equipment, and in other areas in industrial fields. Current structural equipment requires higher efficiency and greater torque levels. According to these needs, we have designed a complex planetary gear system which creates higher levels of torque. In this paper, an evaluation of strength designs for the proposed planetary gear system was conducted to ensure the stability of the gear. In addition, a durability analysis based on Miner's rule was performed using RS B 0095 device.

가속시험을 통한 불규칙하중을 받는 실구조물의 피로수명평가 (Fatigue Life Evaluation of an Actual Structure under the Irregular Loading using an Acceleration Test)

  • 김형익;배봉국;박재실;석창성;모진용
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2004년도 추계학술대회 논문집
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    • pp.166-169
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    • 2004
  • A fatigue test was used to evaluate the fatigue life of an actual structure. The loaded state and the constraint condition of an actual structure must be same as the specimen in order to apply the test results to an actual structure by the specimen. The loaded state and constraint conditions can't be same as the specimen in the actual structure which is complicated. In order to reduce these differences, an actual structure test with a lot of frequencies is need to get a fatigue life curve. Therefore, ten sets of accelerated test units which attached unbalanced mass were composed in this study. Acceleration history about the vibration of an actual structure was acquired. Rainflow counting was used on acceleration history, and the life curve return formula was assumed. The return formula that damage satisfied `1' was acquired in a feedback process by the Miner's rule, which was the linear cumulative damage theory. A conservative fatigue life curve was determined with a return formula to have been presumed by each set. The fatigue life of regular rpm condition was calculated by these conservative fatigue life curves.

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영향계수법과 스펙트럼 해석법을 이용한 선체의 피로강도평가 (Fatigue Strength Assessment of a Ship Structures using the Influence Coefficient Concept and Spectral Analysis Technique)

  • 노인식;김재균;윤장호
    • 대한조선학회논문집
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    • 제34권2호
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    • pp.75-84
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    • 1997
  • 본 연구에서는 스펙트럼 해석법에 기초한 새로운 개념의 정밀한 선체구조 피로강도평가 시스템을 개발하였으며 membrane 방식 LNG 운반선을 대상으로 하여 수치계산을 수행함으로써 그 효용성을 검증하였다. 선체에 작용하는 파랑하중을 스트립 이론으로 직접계산하고 3차원 정밀 구조해석과 영향계수 개념을 바탕으로 Miner 법칙에 의한 누적손상도를 계산하여 설계기준과 비교, 검토하였다.

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공간 데이터 마이닝 시스템의 설계 및 구현 (Design and Implementation of a Spatial Data Mining System)

  • 배덕호;백지행;오현교;송주원;김상욱;최명회;조현주
    • 한국공간정보시스템학회 논문지
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    • 제11권2호
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    • pp.119-132
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    • 2009
  • GIS 기술의 발달로 많은 양의 공간 데이터가 축적됨에 따라 공간 데이터 마이닝의 중요성이 커지고 있다. 본 논문에서는 새로운 공간 데이터 마이닝 시스템 SD-Miner를 제안한다. SD-Miner는 크게 입력과 출력을 담당하는 사용자 인터페이스, 공간 데이터 마이닝 기능을 처리하는 데이터 마이닝 모듈, DBMS를 이용하여 데이터를 저장하고 관리하는 데이터 저장 모듈의 세 부분으로 구성된다. 특히, 데이터 마이닝 함수 모듈에서는 공간 데이터 마이닝의 주요 기법인 공간 클러스터링, 공간 분류, 공간 특성화, 시공 간 연관규칙 탐사 기능을 제공한다. SD-Miner는 다음과 같은 특징을 가진다. SD-Miner는 사용자로 하여 금 공간 데이터 마이닝뿐만 아니라 비 공간 데이터에 대한 마이닝도 가능하게 하며, 각 마이닝 함수들을 라이브러리 형태로 제공하기 때문에 다른 시스템에서도 쉽게 사용 가능하다. 또한, 마이닝 매개 변수들을 테이블의 형태로 입력받기 때문에 시스템의 범용성이 높다. 개발된 SD-Miner의 실용성을 규명하기 위하여 실제 공간 데이터를 이용한 데이터 마이닝을 수행함으로써 여러 가지 의미있는 결과를 도출한다.

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노치응력접근법을 이용한 차량구조재 용접이음부의 피로내구성 해석 (Analysis of Fatigue Durability on Seam Weldment using Notch Stress Approach)

  • 김민건;민태국
    • Journal of Welding and Joining
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    • 제22권2호
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    • pp.28-32
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    • 2004
  • Fatigue life at seam weldment of thick plate was estimated using the finite element and FEM-FAT(an exclusive fatigue solver). Finite element meshing at toe and root of weldment was based oil Radaj's theory. Also, the results of FE analysis were compared with experimental results in the point of Miner's Rule. The results of FE and FEM-FAT analysis were in accord with experimental results within 60% confidence. This result reveals that above techniques is useful in assessment of seam weldment and to be an alternative method instead of an object experiment.

레일용접부 피로수명 예측 (Prediction of bending fatigue lifes of rail welded parts)

  • 양신추;이진욱;나성훈
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 1999년도 춘계학술대회 논문집
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    • pp.390-397
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    • 1999
  • This paper investigates about the prediction of rail bending fatigue lifes for the purpose of the effective maintenance of surface irregularities of rail welded parts. The rail bending stresses are calculated using a track dynamic analysis program. The rail surface irregularities measured in situ are given as inputs in the analyses. On the other hand, the S-N curves are derived based on the results of bending fatigue tests. Using data found so far, rail fatigue lifes are estimated adopting a modified Miner's rule. The useful guides for maintenance of rail welded part are proposed in terms of grinding period and grinding depth of rail surface irregularities.

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주조 알루미늄합금 A356을 사용한 해상구조물의 진동피로수명평가 (Evaluation of Vibration Fatigue Life of Shipboard Equipment Made of Aluminum Alloy A356)

  • 조기대;김지억;양성철;정화영;강기원
    • 대한기계학회논문집A
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    • 제34권9호
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    • pp.1257-1263
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    • 2010
  • 함정구조물은 함내 엔진 및 프로펠러 추진력의 환경진동에 노출되어 있다. 일반적으로 함상구조물은 함상진동규격인 MIL-STD-167-1A 에 따라 개발되고 있으며, 장기간 사용을 목적으로 하는 함상구조물의 진동에 대한 피로수명은 해석적 접근법과 진동실험을 통해 반드시 평가되야 한다. 본 논문에서는 함상구조재로 사용된 주조 알루미늄합금인 A356 의 피로강도를 14 S-N 법으로 평가하고, 구조물의 작용응력은 함상진동규격에 준하는 주파수응답해석을 통해 분석되었다. 최대등가응력의 주파수는 최대실험주파수에서 나타났으며, 함상장비의 진동피로수명은 누적손상법에 의해 평가되었다.

저속 2행정 디젤엔진의 과도 비틀림 진동에 의한 축계 피로 강도에 관한 연구 (A Study on Shaft Fatigue Strength due to Torsional Vibrations in Two Stroke Low Speed Diesel Engines)

  • 이돈출;김상환
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2006년도 추계학술대회논문집
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    • pp.786-791
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    • 2006
  • Two stroke low speed diesel engines are mainly used for marine propulsion or power plant prime mover. These have many merits such as higher thermal efficiency, mobility and durability. However various annoying vibrations sometimes occur in ships or at the plant itself. Of these vibrations, torsional vibration is very important and it should be carefully investigated during the initial design stage for engine's safe operation. In this paper authors suggest a new estimation method of for shaft's can be calculated equivalently from accumulated fatigue cycles number due to torsional vibration. The 6S70MC-C($25,320ps{\times}91rpm$) engine for ship propulsion was selected as a case study, and the accumulated fatigue cycles numbers for shafting life time converted from the measured angular velocity and torsional vibration stress was calculated. This new method can be realized and confirmed in test model ship with two stroke low speed diesel engine.

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랜덤하중하의 GFRP의 피로누적손상거동과 피로수명예측 (The Fatigue Cumulative Damage and Life Prediction of GFRP under Random Loading)

  • 김정규;심동석
    • 대한기계학회논문집A
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    • 제20권12호
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    • pp.3892-3898
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    • 1996
  • In this study, the prediction of the fatigue life as well as the extimation of the characteristics of fatigue cumulative damage on GFRP under random loading were performed. The constant amplitude tests and the ramdom loading test were carried on notched GFRP specimens with a circular hole. Random waves were generated with a micro-computer and had wide band spectra. Since it is useful that the prediction of fatigue life ot the given load sequences is based on S-N curves under constant amplitude loading, the estimation of equivalent stress is done on every random waves. The equivalent stress wasat first estimated by Miner's rule and then by the proposed model which was based on Hashin-Rotem's comulative damage theory regarding nonlinear fatigue cumulative damage behavior. The fatigue lives were predicted from each equivalent stress evaluated. And each predicted fatigue llife was compared with experimental results. The number of cycles of random loads were counted by mean-cross counting method. The reuslts showed that the fatigue life predicted by proposed model was correlated well with the experimental results in comparison with Miner's model.