Understanding Misalignment-Induced Gravity Critical Speed (Subharmonic Resonance) in Rotating Machinery via an Equivalent Base-Excited Pendulum Model

Sang-Jin Park; Huinam Rhee; Daesic Jang; Jeonghan Lee; Jin-Ho Park

doi:10.7734/COSEIK.2026.39.3.143

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2026 Vol.39, Issue 3 Next Page

Research Paper

Understanding Misalignment-Induced Gravity Critical Speed (Subharmonic Resonance) in Rotating Machinery via an Equivalent Base-Excited Pendulum Model 등가 지지점 가진 진자 모델을 이용한 회전기기의 오정렬 유발 중력 위험속도(저조파 공진) 현상의 이해

30 June 2026. pp. 143-151

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Abstract

Machine learning (ML)-based condition-based maintenance (CBM) of rotating machinery requires reliable training datasets, which are difficult to obtain from real operating environments. Because fault data are particularly difficult to obtain from actual operating environments, several studies have focused on generating fault data using computational and numerical methods. Among various mechanical faults in rotating machinery, misalignment faults are caused by the asymmetric stiffness of rotating components, which results in characteristic 2X vibration components and gravity critical speed phenomena. The dynamic behavior caused by misalignment in rotating machinery is fundamentally equivalent to base-excited pendulum (BEP) motion as a type of parametric excitation. Therefore, to artificially generate misalignment fault data and evaluate their physical accuracy and validity, it is necessary to thoroughly understand the fundamental dynamics of BEP motion. Against this backdrop, this study investigates the feasibility and validity of generating time-domain misalignment fault data by simulating BEP motion using a multibody dynamic analysis framework.

Keywords

misalignment

parametric excitation

gravity critical speed

Mathieu equation

multibody dynamics

base-excited pendulum

최근 기계학습(ML) 기반의 회전기기 상태기반정비(CBM) 진단 기술 개발을 위해 학습 데이터 확보가 중요하며, 실제 운전 현장으로부터 확보하기 힘든 결함 데이터를 전산 및 수치적으로 생산하려는 연구들이 수행되고 있다. 회전기기의 다양한 기계적 결함 들 중 오정렬 결함 현상은 회전 부품의 비대칭 강성(asymmetric stiffness)으로부터 기인되어 2X 진동과 gravity critical speed 현상을 발생시킨다. 흥미로운 것은 이러한 회전기기의 오정렬 결함 현상이 파라메트릭 가진 현상(parametric excitation)으로서 본질적으로 지지점 가진 진자(BEP) 운동과 등가적이다는 것이다. 그러므로 회전기기의 오정렬 결함 데이터를 인공적으로 생성하고 그 물리적 정확도와 타당성을 평가하기 위해서는 기초적인 BEP 운동 현상을 충분히 이해할 필요가 있다. 본 연구에서는 이러한 배경을 바탕으로 다물체 동역학(MBD) 해석을 바탕으로 BEP 운동을 시뮬레이션하여 오정렬 결함의 시계열 데이터 생산 가능성과 타당성을 평가하였다

키워드

오정렬

파라메트릭 가진

중력 위험속도

Mathieu 방정식

다물체 동역학

지지점 가진 진자

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Information

Publisher :Computational Structural Engineering Institute of Korea
Publisher(Ko) :한국전산구조공학회
Journal Title :Journal of the Computational Structural Engineering Institute of Korea
Journal Title(Ko) :한국전산구조공학회 논문집
Volume : 39
No :3
Pages :143-151
Received Date : 2026-02-27
Revised Date : 2026-04-08
Accepted Date : 2026-04-27
DOI :https://doi.org/10.7734/COSEIK.2026.39.3.143

Journal of the Computational Structural Engineering Institute of Korea ISSN:1229-3059(Print) 2287-2302(Online) 한국전산구조공학회 논문집

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