• 한국정밀공학회지
• /
• 제12권9호
• /
• pp.137-147
• /
• 1995

The unbalance response analysis is one of the essential area in the forced vibration analysis of rotor-bearing systems. Local bearing parameters in rotor-bearing systems are the major sources which give rise to a difficulty in unbalance response computation due to the complicated dynamic properties such as rotational speed dependency and anisotropy. In the present paper, an efficient method for unbalance responses is proposed so as to easily take into account bearing parameters in computation. An exact matrix condensation procedure is proposed which enables the present method to compute unbalance responses by dealing with condensed, small matrices. The proposed method causes no errors even though the computation procedure is based on the small matrices condensed from the full matrices. The present method is illustrated through a numerical example and compared with the conventional method.

• 소음진동
• /
• 제6권1호
• /
• pp.71-82
• /
• 1996

The finite element analysis for rotor bearing systems has been an essential tool for design, identification, and diagnosis of rotating machinery. Among others, the unbalance response analysis is fundamental in the vibration analysis of rotor bearing systems because rotating unbalance is recognized as a common sourve of vibration in rotating machinery. However there still remains a problem in the aspect of computational efficiency for unbalance response analysis of large rotor bearing systems. Gyroscopic terms and local bearing parameters in rotor bearing systems often make matters worse in unbalance response computation due to the complicated dynamic properties such as rotational speed dependency and/or anisotropy. The present paper proposes an efficient method for unbalance responses of multi-span rotor bearing systems. An improved substructure synthesis scheme is introduced which makes it possible to compute unbalance responses of the system by coupling unbalance responses of substructures that are of self adjoint problem with small order matrices. The present paper also suggests a scheme to easily deal with gyroscopic tems and local, coupling or bearing parameters. The proposed method causes no errors even though the computational effort is reduced drastically. The present method is demonstrated through three test examples.

• 한국식품과학회지
• /
• 제47권2호
• /
• pp.149-157
• /
• 2015

본 연구는 압출성형 된 옥수수 섬유질로부터 화학적 추출을 통해 SAX와 CFG 수율을 향상시키기 위해 반응표면분석법을 이용하여 최적의 압출성형조건을 확립하였다. 압출성형공정 조건 중 수분함량($X_1$), 스크루 회전속도($X_2$), 배럴온도($X_3$)를 독립 변수로 하고 옥수수 섬유질의 residual solid, final solution, 그리고 CFG의 수율과 각각의 SAX값을 종속 변수로 하여 화학적으로 추출 하였다. 그 결과, 수율의 경우 final solution은 EDCF가 DCF보다 낮은 경향을 보였고, residual solid와 CFG의 경우, EDCF가 DCF보다 높은 경향을 나타내었다. SAX값은 모든 조건의 EDCF가 DCF보다 높은 경향을 나타냈다. 각각의 결정된 최적의 압출성형 조건에서 분석한 결과 모든 조건에서 예측값과 결과값이 유사하여 반응표면 분석의 결과가 양호한 것으로 나타났다. 이상의 연구결과에서 반응표면 분석법이 압출성형 공정에 의한 CFG의 수율과 총 SAX값의 최적화를 위한 적절한 방법 중 하나라는 것을 보여주었다.