Three-dimensional nonlinear dynamics and vibration reduction of gear pairs and planetary gears
Başlık çevirisi mevcut değil.
- Tez No: 403436
- Danışmanlar: Prof. ROBERT G. PARKER
- Tez Türü: Doktora
- Konular: Makine Mühendisliği, Mechanical Engineering
- Anahtar Kelimeler: Belirtilmemiş.
- Yıl: 2011
- Dil: İngilizce
- Üniversite: The Ohio State University
- Enstitü: Yurtdışı Enstitü
- Ana Bilim Dalı: Belirtilmemiş.
- Bilim Dalı: Belirtilmemiş.
- Sayfa Sayısı: 217
Özet
Özet yok.
Özet (Çeviri)
This work aims to provide insight into the three-dimensional vibration of gears by investigating the mechanisms of excitation and nonlinearity coming from the gear tooth mesh. The focus is on gear pairs and planetary gears. The forces and moments generated at the gear tooth mesh cause three-dimensional relative displacements of contacting gear tooth, which disengage portions of gear tooth surface (partial contact loss) nominally designed to be in contact. While complete tooth disengagement (total contact loss) is the most commonly recognized nonlinearity in gears, partial contact loss is also a source of nonlinearity. A three-dimensional lumped-parameter gear mesh model produces the net force and moment at the gear mesh due to an arbitrary load distribution on the gear tooth surface using a translational and twist spring. Thus, the three-dimensional lumped-parameter model, named the equivalent stiffness model, concisely captures the nonlinear behavior. Both translational and twist stiffnesses depend strongly on spatial displacements at the gear mesh, and so are highly nonlinear and time-dependent. The twist moment periodically fluctuates over a mesh cycle, causing twist vibrations. With gear pairs, there is a twist vibration mode, where the twist stiffness is active, and a mesh deflection mode, where the translational stiffness is active. The dynamic response is nonlinear due to partial and total contact loss. The dynamic displacements distorts the instantaneous dynamic contact loads compared with the static design contact loads. To quantitatively assess nonlinear vibrations of gear pairs, a method is developed to give a closed-form analytical expression of the frequency-amplitude curve. Partial contact loss is captured with quadratic and cubic nonlinear terms. The vibration excitation comes from the time-dependent fluctuations due to periodic tooth engagement. The closed-form solution, found using the method of multiple scales, enables immediate calculation of nonlinear dynamic response, stability of the response, and the frequency range of total contact loss. With planetary gears, modes of vibration are crucial in understanding and reducing vibration. For equally-spaced planetary gears, all vibration modes belong to three types: 1) Rotational-axial modes (named for the displacements of the central members), 2) Translational-tilting modes (named for the displacements of the central members), and 3) Planet modes (only planets are active). This classification is mathematically derived. It depends only on planet spacing, and thus persists for axial asymmetry, e.g., use of helical gears, overhung shafts, different bearings at shaft ends. Planet spacing and gear tooth counts in planetary gears, when selected based on a set of rules, eliminate some force and moment fluctuation harmonics. It is shown that these fluctuations stem from the relative phase between planet gear meshes. The set of rules that eliminate force and moment fluctuations are derived. The derivation relies solely on the circumferential symmetry, so it is equally valid for static and dynamic conditions, elastic or rigid components, and for axially asymmetric systems.
Benzer Tezler
- Dynamic response and active control of flexible cylindrical structures undergoing vortex-induced vibrations
Başlık çevirisi yok
ERSEGUN DENİZ GEDİKLİ
- Hidrofoillerin kavitasyon kovalarının sayısal-parametrik incelenmesi
Numerical investigation cavitation buckets for hydrofoil parametrically
MEHMET SALİH KARAALİOĞLU
Yüksek Lisans
Türkçe
2015
Gemi Mühendisliğiİstanbul Teknik ÜniversitesiGemi İnşaatı ve Gemi Makineleri Mühendisliği Ana Bilim Dalı
PROF. DR. ŞAKİR BAL
- Kriging interpolasyonu kullanan vekil modeller ile gemi kıç formunun viskoz direnç yönünden optimizasyonu
Aft form optimization of ships for minimum viscous resistance by using kriging metamodeling technique
HAYRİYE PEHLİVAN SOLAK
Doktora
Türkçe
2020
Gemi Mühendisliğiİstanbul Teknik ÜniversitesiGemi İnşaatı ve Gemi Makineleri Mühendisliği Ana Bilim Dalı
PROF. DR. ÖMER GÖREN
- A parallel monolithic approach for the numerical simulation of fluid-structure interaction problems
Akışkan-yapı etkileşimi problemlerinin sayısal simülasyonu için paralel monolitik bir yöntem
ALİ EKEN
Doktora
İngilizce
2016
Havacılık Mühendisliğiİstanbul Teknik ÜniversitesiUçak ve Uzay Mühendisliği Ana Bilim Dalı
YRD. DOÇ. DR. HAYRİ ACAR
DOÇ. DR. MEHMET ŞAHİN