85 research outputs found
Modeling and Analysis of Nonlinear Dynamic Behavior of Rotors
No full textL'objectif de ce travail de thèse est d'étudier analytiquement et numériquement le comportementdynamique non-linéaire des rotors, en prenant en compte des effets significatifs comme les grandesdéformations en flexion, les non-linéarités géométriques et le cisaillement. Le manuscrit est diviséen trois parties principales. Dans la première partie, le principe de Hamilton est utilisé pour formulerles équations du mouvement qui prennent en compte un ensemble d’effets non-linéaires comme desdéformations d'ordre supérieur en flexion et le cisaillement. De plus, si les supports du rotor nepermettent pas à l'arbre de se déplacer dans la direction axiale, il y a alors une force dynamiqueharmonique agissant axialement sur le rotor en fonctionnement. Ces modèles se composentd’équations différentielles non-linéaires du deuxième et du quatrième ordre.Les deux parties suivantes sont consacrées à la résolution des différents modèles non-linéairesdéveloppés dans la première partie. Des méthodes analytiques et numériques sont appliquées afin detraiter les équations non-linéaires du mouvement. Une méthode basée sur des développementsasymptotiques, la méthode des échelles multiples (MEM) est utilisée. Les courbes de réponse sonttracées pour différentes résonances possibles et l'effet de la non-linéarité est discuté par rapport àl'analyse linéaire. La réponse forcée du système provoquée par un balourd est également présentéepour plusieurs configurations du rotor. Lorsque les déformations de cisaillement sont prises encompte, l'analyse est effectuée pour différents élancements afin de mettre en évidence cet effet sur ladynamique d’un système arbre-disqueThe objective of the present work is to investigate the nonlinear dynamic behavior of the rotorsystems analytically and numerically, taking into account the significant effects, for example, higherorder large deformations in bending, geometric nonlinearity and shear effects.This thesis is dividedinto two major parts. In the first part, Hamilton’s principle is used to derive the equations of motionwhich take into account various effects, for example, nonlinearity due to higher order largedeformations in bending and shear effects. In addition, if the supports of the rotor do not allow theshaft to move in the axial direction, then there will be a dynamical force acting axially on the rotoras it operates. The mathematical models are composed of coupled nonlinear differential equations ofthe 2nd and the 4th order.In the second part, the resolution of various nonlinear models developed in the first part isaddressed. Analytical and numerical methods are applied for treating the nonlinear equations ofmotion. A method based on asymptotic developments, the method of multiple scales (MMS) is used.The response curves are plotted for different possible resonance conditions and the effect ofnonlinearity is discussed with respect to the linear analysis. The forced response of the system due toa mass unbalance is also presented for various configurations of the rotor. When shear deformationsare taken into account, the analysis is performed for various slenderness ratios to highlight sheareffects on the dynamics of the shaft-disk rotor system
Modélisation et Analyse du Comportement Dynamique Non-linéaire des Rotors
No full textL'objectif de ce travail de thèse est d'étudier analytiquement et numériquement le comportement\ud
dynamique non-linéaire des rotors, en prenant en compte des effets significatifs comme les grandes\ud
déformations en flexion, les non-linéarités géométriques et le cisaillement. Le manuscrit est divisé\ud
en trois parties principales. Dans la première partie, le principe de Hamilton est utilisé pour formuler\ud
les équations du mouvement qui prennent en compte un ensemble d’effets non-linéaires comme des\ud
déformations d'ordre supérieur en flexion et le cisaillement. De plus, si les supports du rotor ne\ud
permettent pas à l'arbre de se déplacer dans la direction axiale, il y a alors une force dynamique\ud
harmonique agissant axialement sur le rotor en fonctionnement. Ces modèles se composent\ud
d’équations différentielles non-linéaires du deuxième et du quatrième ordre.\ud
Les deux parties suivantes sont consacrées à la résolution des différents modèles non-linéaires\ud
développés dans la première partie. Des méthodes analytiques et numériques sont appliquées afin de\ud
traiter les équations non-linéaires du mouvement. Une méthode basée sur des développements\ud
asymptotiques, la méthode des échelles multiples (MEM) est utilisée. Les courbes de réponse sont\ud
tracées pour différentes résonances possibles et l'effet de la non-linéarité est discuté par rapport à\ud
l'analyse linéaire. La réponse forcée du système provoquée par un balourd est également présentée\ud
pour plusieurs configurations du rotor. Lorsque les déformations de cisaillement sont prises en\ud
compte, l'analyse est effectuée pour différents élancements afin de mettre en évidence cet effet sur la\ud
dynamique d’un système arbre-disque.--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------The objective of the present work is to investigate the nonlinear dynamic behavior of the rotor\ud
systems analytically and numerically, taking into account the significant effects, for example, higher\ud
order large deformations in bending, geometric nonlinearity and shear effects.This thesis is divided\ud
into two major parts. In the first part, Hamilton’s principle is used to derive the equations of motion\ud
which take into account various effects, for example, nonlinearity due to higher order large\ud
deformations in bending and shear effects. In addition, if the supports of the rotor do not allow the\ud
shaft to move in the axial direction, then there will be a dynamical force acting axially on the rotor\ud
as it operates. The mathematical models are composed of coupled nonlinear differential equations of\ud
the 2nd and the 4th order.\ud
In the second part, the resolution of various nonlinear models developed in the first part is\ud
addressed. Analytical and numerical methods are applied for treating the nonlinear equations of\ud
motion. A method based on asymptotic developments, the method of multiple scales (MMS) is used.\ud
The response curves are plotted for different possible resonance conditions and the effect of\ud
nonlinearity is discussed with respect to the linear analysis. The forced response of the system due to\ud
a mass unbalance is also presented for various configurations of the rotor. When shear deformations\ud
are taken into account, the analysis is performed for various slenderness ratios to highlight shear\ud
effects on the dynamics of the shaft-disk rotor systems
Biomass for renewable energy production in Pakistan: current state and prospects [Latest Articles]
No full textModeling and Analysis of Nonlinear Dynamic Behavior of Rotors
No full textL'objectif de ce travail de thèse est d'étudier analytiquement et numériquement le comportementdynamique non-linéaire des rotors, en prenant en compte des effets significatifs comme les grandesdéformations en flexion, les non-linéarités géométriques et le cisaillement. Le manuscrit est diviséen trois parties principales. Dans la première partie, le principe de Hamilton est utilisé pour formulerles équations du mouvement qui prennent en compte un ensemble d effets non-linéaires comme desdéformations d'ordre supérieur en flexion et le cisaillement. De plus, si les supports du rotor nepermettent pas à l'arbre de se déplacer dans la direction axiale, il y a alors une force dynamiqueharmonique agissant axialement sur le rotor en fonctionnement. Ces modèles se composentd équations différentielles non-linéaires du deuxième et du quatrième ordre.Les deux parties suivantes sont consacrées à la résolution des différents modèles non-linéairesdéveloppés dans la première partie. Des méthodes analytiques et numériques sont appliquées afin detraiter les équations non-linéaires du mouvement. Une méthode basée sur des développementsasymptotiques, la méthode des échelles multiples (MEM) est utilisée. Les courbes de réponse sonttracées pour différentes résonances possibles et l'effet de la non-linéarité est discuté par rapport àl'analyse linéaire. La réponse forcée du système provoquée par un balourd est également présentéepour plusieurs configurations du rotor. Lorsque les déformations de cisaillement sont prises encompte, l'analyse est effectuée pour différents élancements afin de mettre en évidence cet effet sur ladynamique d un système arbre-disqueThe objective of the present work is to investigate the nonlinear dynamic behavior of the rotorsystems analytically and numerically, taking into account the significant effects, for example, higherorder large deformations in bending, geometric nonlinearity and shear effects.This thesis is dividedinto two major parts. In the first part, Hamilton s principle is used to derive the equations of motionwhich take into account various effects, for example, nonlinearity due to higher order largedeformations in bending and shear effects. In addition, if the supports of the rotor do not allow theshaft to move in the axial direction, then there will be a dynamical force acting axially on the rotoras it operates. The mathematical models are composed of coupled nonlinear differential equations ofthe 2nd and the 4th order.In the second part, the resolution of various nonlinear models developed in the first part isaddressed. Analytical and numerical methods are applied for treating the nonlinear equations ofmotion. A method based on asymptotic developments, the method of multiple scales (MMS) is used.The response curves are plotted for different possible resonance conditions and the effect ofnonlinearity is discussed with respect to the linear analysis. The forced response of the system due toa mass unbalance is also presented for various configurations of the rotor. When shear deformationsare taken into account, the analysis is performed for various slenderness ratios to highlight sheareffects on the dynamics of the shaft-disk rotor systemsTOULOUSE-INSA-Bib. electronique (315559905) / SudocSudocFranceF
Synergizing AI and HRM: Leveraging Business Analytics for a Future-Ready Workforce
No full textThis chapter explores the integration of Artificial Intelligence (AI) and Human Resource Management (HRM) practices within the Asian business landscape. It offers a comprehensive examination of the evolution of AI in HRM, emphasizing the benefits and potential challenges associated with implementing AI-driven HRM strategies. The discussion highlights the importance of synergizing AI and HRM through business analytics, offering insights into how AI can enhance recruitment, retention, and employee engagement. The author delve into potential ethical, cultural, and legal issues associated with AI-driven HRM, highlighting the necessity for thoughtful and strategic implementation. Finally, the chapter proposes strategies for successfully incorporating AI in HRM, emphasizing the development of AI competencies, fostering a data-driven culture, and ensuring ethical AI deployment. The discussion provides a foundation for future research, policy development, and practical applications in AI-driven HRM, promoting a future-ready workforce in Asia
Nonlinear Dynamics of Rotors due to Large Deformations and Shear Effects
No full textAn analysis of linear and nonlinear dynamics of rotors is presented taking into account the shear effects. The nonlinearity arises due to the consideration of large deformations in bending. The rotor system studied is composed of a rigid disk and a circular shaft. In order to study the combined effect of rotary inertia and shear effects the shaft is modeled as a Timoshenko beam of circular cross section. A mathematical model is developed consisting of 4th order coupled nonlinear differential equations of motion. Method of multiple scales is used to solve these nonlinear equations. Linear and nonlinear dynamic behavior is studied numerically for different values of slenderness ratio r. Resonant curves are plotted for the nonlinear analysis. Due to nonlinearity these curves are of hard spring type. This spring hardening effect is more visible for lower values of r. Also the nonlinear response amplitude is higher when shear deformations are taken into account.</jats:p
Analytical study of the dynamic behavior of geometrically nonlinear shaft-disk rotor systems
No full textInternational audienceThis paper explores analytically the nonlinear dynamic behavior of rotors. Coupled nonlinear equations of motion are formulated using Hamilton’s principle. The rotor model is composed of a rigid disk and a flexible shaft which is characterized as a beam of circular cross section. Various influences are taken into account like the effect of higher order large deformations, rotary inertia, gyroscopic effect, rotor unbalance and the effect of a dynamic axial force. Forced response due to a mass unbalance is presented first for the linear analysis and then perturbation techniques are used to solve the complete equations of motion including nonlinear terms. Method of multiple scales is applied to examine the nonlinear behaviour of the rotor system. Resonant curves are plotted for different possible resonance conditions. It is concluded that the higher order large deformations and axial force acting dynamically on the rotor have a significant effect on its nonlinear response. This response varies for different parameters of the rotor like an unbalance mass and diameter of the shaft
Novel CO2 Separation Membranes
No full textUsing membranes for CO2 capture has gained recent prominence in the global scientific community due to its lower capital cost and a quicker separation performance than the conventional separation methods. The membrane process features desirable properties, like compactness, energy efficiency, and environmental friendliness. Various polymeric and inorganic materials have been tested both as unique ingredients and blends to form CO2 separation membranes with a focus on increasing the performance but have had varying rates of success. For commercial viability, the membrane sector requires new techniques and testing materials to lower the cost of CO2 capture. Recently, thermally rearranged polymers, intrinsic microporous polymers, ionic liquid inclusion as fillers, and binary fillers have all emerged as novel trends, focusing on enhancing the working efficiency and sustainability of the membranes. This chapter explores the most recent advances in membrane technology and its future prospects as a sustainable solu ion towards carbon dioxide capture. This Page is compulsory Book Title – Sustainable Carbon Capture: Technologies and Applications Chapter Author(s) – Asif Jamil, Department of Chemical Polymer and Composite Material Engineering, University of Engineering and Technology (New Campus), Lahore, Pakistan, [email protected] Muhammad Latif, Institute of Energy and Environmental Engineering, University of the Punjab, 54590, Lahore, Pakistan, [email protected] Alamin Idris Abdulgadir, Department of Engineering and Chemical Sciences, Karlstad University, SE-651 88 Karlstad, Sweden, [email protected] Danial Qadir, Centre for Sustainable Engineering, Teesside University, Middlesbrough, United Kingdom, [email protected] Hafiz Abdul Mannan, Institute of Polymer and Textile Engineering, University of the Punjab, 54590, Lahore, Pakistan, [email protected]</p
Cross-Genre Author Profile Prediction Using Stylometry-Based Approach Notebook for PAN at CLEF 2016
No full textAbstract.Author profiling task aims to identify different traits of an author by analyzing his/her written text. This study presents a Stylometry-based approach for detection of author traits (gender and age) for cross-genre author profiles. In our proposed approach, we used different types of stylistic features including 7 lexical features, 16 syntactic features, 26 character-based features and 6 vocabulary richness (total 56 stylistic features). On the training corpus, the proposed approach obtained promising results with an accuracy of 0.787 for gender, 0.983 for age and 0.780 for both (jointly detecting age and gender). On the test corpus, proposed system gave an accuracy of 0.576 for gender, 0.371 for age and 0.256 for both
- …
