• 제목/요약/키워드: linearity analysis

검색결과 1,161건 처리시간 0.033초

Analysis of Orthotropic Bearing Non-linearity Using Non-linear FRFs

  • Han Dong-Ju
    • Journal of Mechanical Science and Technology
    • /
    • 제20권2호
    • /
    • pp.205-211
    • /
    • 2006
  • Among other critical conditions in rotor systems the large non-linear vibration excited by bearing non-linearity causes the rotor failure. For reducing this catastrophic failure and predictive detection of this phenomenon the analysis of orthotropic bearing non-linearity in rotor system using higher order frequency response functions (HFRFs) is conducted and is shown to be theoretically feasible as that of non-rotating structures. The complex HFRFs based on the Volterra series are newly developed for the process and investigated their features by using the simple forms of the FRFs associated with the forward and the backward modes.

재료의 비선형성을 고려한 후육 정사각튜브의 좌굴에 관한 연구 (A Study on the Buckling Analysis of the Thick-walled Square Tubes)

  • 한병기;박봉현;정태은;홍승준
    • 한국자동차공학회논문집
    • /
    • 제6권2호
    • /
    • pp.228-234
    • /
    • 1998
  • The buckling is one of the major two nonlinear problems. One is the material non-linearity and other is the geometrical nonlinear. Material non-linearity has occurred when the buckling stress of material exceeded the yield stress of material. The material non-linearity must be taken into account when the buckling analysis of thick plate is performed. In this study, inelastic modulus that is used to calculate the buckling strength is taken to account for the material non-linearity. The results from experiments are used to formulate the semi-theoretical formula. The analysis results generated by the use of semi-theoretical formula are close to the experimental data.

  • PDF

가변적인 샘플링을 이용한 차원 감소법에 의한 신뢰도 해석 기법 (Reliability Analysis Using Dimension Reduction Method with Variable Sampling Points)

  • 육순민;민준홍;김동호;최동훈
    • 대한기계학회논문집A
    • /
    • 제33권9호
    • /
    • pp.870-877
    • /
    • 2009
  • This study provides how the Dimension Reduction (DR) method as an efficient technique for reliability analysis can acquire its increased efficiency when it is applied to highly nonlinear problems. In the highly nonlinear engineering systems, 4N+1 (N: number of random variables) sampling is generally recognized to be appropriate. However, there exists uncertainty concerning the standard for judgment of non-linearity of the system as well as possibility of diverse degrees of non-linearity according to each of the random variables. In this regard, this study judged the linearity individually on each random variable after 2N+1 sampling. If high non-linearity appeared, 2 additional sampling was administered on each random variable to apply the DR method. The applications of the proposed sampling to the examples produced the constant results with increased efficiency.

가변적인 샘플링을 이용한 신뢰도 해석 기법 (Reliability Analysis Method with Variable Sampling Points)

  • 육순민;최동훈
    • 대한기계학회:학술대회논문집
    • /
    • 대한기계학회 2008년도 추계학술대회A
    • /
    • pp.1162-1168
    • /
    • 2008
  • This study provides how the Dimension Reduction (DR) method as an efficient technique for reliability analysis can acquire its increased efficiency when it is applied to highly nonlinear problems. In the highly nonlinear engineering systems, 4N+1 (N: number of random variables) sampling is generally recognized to be appropriate. However, there exists uncertainty concerning the standard for judgment of non-linearity of the system as well as possibility of diverse degrees of non-linearity according to each of the random variables. In this regard, this study judged the linearity individually on each random variable after 2N+1 sampling. If high non-linearity appeared, 2 additional sampling was administered on each random variable to apply the DR method. The applications of the proposed sampling to the examples produced the constant results with increased efficiency.

  • PDF

Analysis of differential non-linearity of successive approxination ADC

  • Yamada, Hikaru
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
    • /
    • pp.943-946
    • /
    • 1989
  • The channel irregularity of Successive Approximation ADC is very large in comparison with other type of ADCs. This characteristic makes it impossible to apply the Successive Approximation ADC to the field of radiation pulse height analysis or the measurement of probability density function. In this paper, an analysis of differential non-linearity of this ADC-is presented. It is made clear that the small deviation of resistance causes very large differential non-linearity.

  • PDF

수치해석을 통한 충격 시 접시 스프링의 비선형 특성 고찰 (Non-linearity characteristics consideration of the Disc Spring under Shock using Numerical Analysis)

  • 방승우;이해진;권오철;이정윤;오재응
    • 한국소음진동공학회:학술대회논문집
    • /
    • 한국소음진동공학회 2007년도 추계학술대회논문집
    • /
    • pp.1266-1271
    • /
    • 2007
  • General coil spring has linearity. However, disc spring has non-linearity so that using this non-linearity disc spring can be designed to do shock-absorbing in cases we need because shock response also has non-linearity. By changing the shape and stacking number, it is satisfactory with response of displacement, velocity and acceleration. Conventionally, disc spring was used to control the vibration against huge load and limited space. However, it is limitedly used because of difficulty of the designing guidance. Therefore, disc spring is needed to study further in order to apply it widely. Response of disc spring is compared to response of coil spring by changing ho/t radio with computer simulation and the usage of disc spring is increased through analysis of effect of design factors. The purpose of this paper is that the shock response of disc spring is calculated through numerical simulation and effect of ho/t and stiffness is analyzed to broad usage so that design factor of disc spring is presented.

  • PDF

수치해석을 통한 충격 시 접시 스프링의 비선형 특성 고찰 (Non-linearity Characteristics Consideration of the Disc Spring Under Shock Using Numerical Analysis)

  • 방승우;이해진;심현진;박상길;이정윤;오재응
    • 한국소음진동공학회논문집
    • /
    • 제18권2호
    • /
    • pp.153-159
    • /
    • 2008
  • General coil spring has linearity. However, disc spring has non-linearity so that using this non-linearity disc spring can be designed to do shock-absorbing in cases we need because shock response also has non-linearity. By changing the shape and stacking number, it is satisfactory with response of displacement, velocity and acceleration. Conventionally, disc spring was used to control the vibration against huge load and limited space. However, it is limitedly used because of difficulty of the designing guidance. Therefore, disc spring is needed to study further in order to apply it widely. Response of disc spring is compared to response of coil spring by changing $h_o/t$ ratio with computer simulation and the usage of disc spring is increased through analysis of effect of design factors. The purpose of this paper is that the shock response of disc spring is calculated through numerical simulation and effect of $h_o/t$ and stiffness is analyzed to broad usage so that design factor of disc spring is presented.

Identification of Anisotropic Bearing Non-linearity

  • Han, Dong-Ju
    • International Journal of Aeronautical and Space Sciences
    • /
    • 제5권2호
    • /
    • pp.35-42
    • /
    • 2004
  • Among other critical conditions in rotor svstems the large non-linearvibration excited by bearing non-linearity causes the rotor failure. For reducing thiscatastrophic failure and predictive analysis of this phenomena the identificationanalysis of bearing non-linearity in an anisotropic rotor system using the higherorder dFRFs are developed and are shown to be theoretically feasible as innon-rotating structures. For the identification of the anisotropic rotor withanisotropic bearing non-linearity expressed by the displacement in polynomial form,the higher order dFRFs based upon the Volterra series are investigated and depicttheir features by using the simple forms of the normal and reverse dFRFs. Theyproduce additional sub-harmonic resonant peaks, which indicate the existence ofhigher order non-linearties, and show the energy transfer such that the modes fornormal and reuerse dFRFs are exchanged, which are the fundamental differencesfrom what we can expect in linear ones.