• Title/Summary/Keyword: Goodman Diagram

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An Evaluation of the Fatigue Properties for External Panel Using Low Density SMC (저비중 SMC 외장패널의 피로특성 평가)

  • Kim, Eun-Sung
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.21 no.5
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    • pp.830-835
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    • 2012
  • A research for application of LDSMC(Low Density Sheet Molding Compound) composite is in progress for lightening the weight. This paper has performed fatigue test and simulation of external panel for Korean commercial vehicle. Before the fatigue test, static test was carried out. From the test, the structural safety was investigated using Goodman diagram. After the static test performance, the fatigue test was conducted at a range of load frequency 5Hz, a stress ratio(R) of 0.05 and an endurance limit of $10^6$ to obtain the S-N curve. The S-N curve is applied to the fatigue analysis of the external panel assembly. The result of FEM analysis was in accord with the experimental result within 83% confidence. It showed that the process to set up the safety range of allowable error is required in process of the design and simulation verification.

Safety Evaluation of Bogie Frame for Tilting Railway Vehicles by Fatigue and Nondestructive Tests (피로시험 및 비파괴 검사를 통한 틸팅열차용 주행장치 프레임의 안전성 평가)

  • Kim Jung-Seok;Kim Nam-Po
    • Journal of the Korean Society for Railway
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    • v.8 no.5
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    • pp.419-424
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    • 2005
  • This paper has performed fatigue and nondestructive test of bogie frame for Korean tilting train. Before the fatigue test, static tests were carried out. From the test, the structural safety was investigated using Goodman diagram. After the static test, the fatigue test were conducted under tilting load conditions. The fatigue test was conducted for $10{\times}10^6$ cycles. During the fatigue test, the nondestructive tests using magnetic particle and liquid penetrant were performed at $6{\times}10^6$ cycle and $10{\times}10^6$cycle. From the crack detection tests, it was known that there was no fatigue crack in the bogie frame.

Fatigue Life Evaluation Model for Welded feints Based on Nominal Stress and Residual Stress Relaxation (잔류응력 완화를 고려한 공칭응력 기반 용접재의 피로수명 평가 모델)

  • 구병춘;양승용;정흥채;최성규
    • Proceedings of the KWS Conference
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    • 2004.05a
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    • pp.249-251
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    • 2004
  • According to our fatigue tests carried out at 20 ㎐, R=0.1 on transversely butt-welded joints, fatigue strengths of as-welded specimens, that is, specimens having residual stress are higher than those of annealed specimens in short hie range, but vice verse in long life range. This behavior seems to be concerned mainly with residual stress relaxation by applied loading. After analyzing the welding process, we conducted finite element analysis to quantify the degree of residual stress relaxation. By taking into account residual stress relaxation, modified Goodman diagram, and nominal stress, we evaluated the fatigue life of the welded joint from the S-N curve for the parent material. The estimated results are in a good agreement with the experimental results.

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Strength Evaluation for Bolster of Korean Tilting Train by Static and Fatigue Tests (정적 및 피로시험에 의한 틸팅열차용 볼스터의 구조강도평가)

  • Kim Nam-Po;Kim Jung-Seok
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.30 no.2 s.245
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    • pp.210-218
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    • 2006
  • This paper has performed static, fatigue and nondestructive test of tilting' bolster frame for Korean tilting train. From the static test, the structural safety was investigated using Goodman diagram. After the static test, the fatigue test were conducted under tilting load conditions. The fatigue test was conducted for $10\times10^6$ cycles. During the fatigue test, the nondestructive tests using magnetic particle and liquid penetrant were performed at $6\times10^6$cycle and $10\times10^6$cycle. From the crack detection tests, it was known that there was no fatigue crack in the tilting bolster.

Characteristic of fatigue properties with tension and bending loading using high strength steel wire (고강도 강선의 인장 및 회전굽힘 피로특성)

  • Woo, Byung-Chul;Kim, Sang-Soo;Kim, Byung-Guel;Suh, Chang-Min
    • Proceedings of the KSME Conference
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    • 2000.11a
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    • pp.274-279
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    • 2000
  • The overhead transmission wires operating both at warm temperature and tighten state for a long period of time in a power transmission plant are degraded by air pollution, wind, creep and slip between steel wire and aluminium conductor. The objective of this study is to investigate a high carbon steel wire. We tested for basic mechanical properties and 3 types fatigue behavior, tension-tension, 4 points bending and 3 points bending fatigues. In this study, a conventional fatigue strengths between 4 points bending and tension-tension fatigue were determined by Gerber, Sorderberg and Goodman's theory and we investigated S-N diagram for bending and tensile loading.

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Fatigue Strength Evaluation of Wind Turbine Hub (풍력 터빈 허브의 피로강도 평가)

  • Lee, Hyun-Joo;Koh, Jang-Wook;Oh, Si-Doek
    • Proceedings of the KSME Conference
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    • 2003.11a
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    • pp.1033-1038
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    • 2003
  • A wind turbine obtains its power input by converting the force of the wind into a torque (turning force) acting on the rotor blades. The amount of energy which the wind transfers to the rotor depends on the density of the air, the rotor area, and the wind speed. Because it has long term operating life and very complex load condition, the fatigue strength of each component must be considered. In this paper, we calculated the load condition by wind using a combined blade elemental theory and a FEM based analytical approach was use to evaluate the fatigue strength of a Hub of wind turbine. The effect of tensile mean stress was taken into account by the modified Goodman diagram. Using this approaches, we evaluated the fatigue strength of hub and main shaft and improved the design.

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A Study on Failure Analysis of Turbine Blade Using Surface Roughness and FEM (표면거칠기와 유한요소법을 이용한 터빈 블레이드의 파손해석에 관한 연구)

  • 홍순혁;이동우;이선봉;조석수;주원식
    • Transactions of the Korean Society of Automotive Engineers
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    • v.9 no.6
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    • pp.170-177
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    • 2001
  • Turbine blade is subject to torsional load by torsion-mount, centrifugal load by rotation of rotor and repeated bending load by steam pressure. Turbine with partially cracked blade has normal working condition at initial repair time but vibratory working condition at middle repair time due to crack growth. Finite element analysis on turbine blade indicates that repeated bending load out of all loads is the most important factor on fatigue strength of turbine blade. Therefore, this study shows root mean square roughness has linear relation with stress intensity factor range in 12% Cr steel and can predict loading condition of fractured turbine blade.

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Fatigue Life Evaluation of Welded Joints With Residual Stress (잔류응력을 고려한 용접 이음부의 피로수명 평가 모델)

  • Goo, B.C.;Yang, S.Y.
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.108-113
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    • 2004
  • According to our fatigue tests carried out at 20 Hz, R=0.1 on transversely butt~welded joints, fatigue strengths of as-welded specimens, that is, specimens having residual stress are higher than those of annealed specimens in short life range, but vice verse in long life range. This behavior seems to be concerned mainly with residual stress relaxation by applied loading. After analyzing the welding process, we conducted finite element analysis to quantify the degree of residual stress relaxation. By taking into account residual stress relaxation, modified Goodman diagram, and nominal stress, we evaluated the fatigue life of the welded joint from the S-N curve for the parent material. The estimated results are in a good agreement with the experimental results.

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Evaluation for Fatigue Resistance of Small Wind Turbine Composite Blade according to GL Guideline (GL Guideline에 의거한 소형 풍력발전용 복합재 블레이드의 피로 저항성 평가)

  • Jang, Yun Jung;Kang, Ki Weon
    • The KSFM Journal of Fluid Machinery
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    • v.16 no.4
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    • pp.15-21
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    • 2013
  • This study aims to estimate the fatigue resistance of small wind composite blade using the fatigue life estimation formula in the GL guideline. For this, firstly, we estimated a turbine blade's bending moment spectrum by using wind profile wind profile and BEMT. And fatigue tests were performed to obtain the S-N curve of composite materials used in blade. In addition, a finite element analysis was used to identify fatigue critical locations and fatigue stress spectrum. And the fatigue resistance of composite blade were evaluated using the rainflow cycle counting, and Goodman diagram and the fatigue life estimation formula in the GL guideline.

A Study on the Evaluation of Tension-Compression Fatigue Characteristics of Glass Fiber/Epoxy 4-Harness Satin Woven Laminate Composite for the Railway Bogie Application (철도차량 대차 적용 유리섬유/에폭시 4-매 주자직 적층 복합재의 인장-압축 피로특성 평가 연구)

  • Jeon, Kwang-Woo;Shin, Kwang-Bok;Kim, Jung-Seok
    • Composites Research
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    • v.23 no.5
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    • pp.22-29
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    • 2010
  • This paper describes the evaluations of tension-compression fatigue characteristics and life for glass fiber/epoxy laminate composite applied to railway bogie to reduce weight. Test samples of tension-compression fatigue were composed of glass fiber/epoxy 4-harness woven laminate composites with different stacking sequence of warp-direction, fill-direction and ${\pm}45^{\circ}$-direction. The tension-compression fatigue test was conducted with stress ratio (R) of -1 and frequency of 5Hz. Goodman diagram were used to evaluate the fatigue characteristics and life of glass fiber/epoxy 4-harness satin woven laminate composite. Anti-buckling jig was designed to prevent buckling of specimen under compression load. The test results showed that the fatigue characteristics of glass fiber/epoxy 4-harness satin woven laminate composite with stacking sequence of warp-direction had a good performance in comparison with that of SM490 used to conventional metal railway bogie.