Vibrations of Flexible Multistage Rotor Systems Supported by Water-Lubricated Rubber Bearings

2017 ◽  
Vol 139 (2) ◽  
Author(s):  
Shibing Liu ◽  
Bingen Yang
Keyword(s):  
Vibration Analysis ◽  
Numerical Study ◽  
Modeling And Analysis ◽  
Rotor Systems ◽  
The Past ◽  
Steady State Responses ◽  
And Performance ◽  
Distributed Transfer Function ◽  
Rubber Bearings ◽  
State Responses

Flexible multistage rotor systems that are supported by water-lubricated rubber bearings (WLRBs) are seen in various engineering applications. Vibration analysis is important to design and performance of such dynamic systems. In the past, due to the lack of reliable models of WLRBs, vibration analysis of this type of rotor systems has not been well addressed. In this paper, a method for modeling and analysis of WLRB-supported multistage rotor systems is proposed. In the development, a new model of WLRBs is integrated with a distributed transfer function formulation, which eventually yields accurate results on the eigensolutions, critical speeds, and steady-state responses of WLRB-supported rotor systems. The proposed method is illustrated in a numerical study on a three-stage rotor system. It is shown that the proposed method provides a useful tool for optimal design of flexible multistage rotor systems with WLRBs.

Modeling and Analysis of Flexible Multistage Rotor Systems With Water-Lubricated Rubber Bearings

2014 ◽  
Author(s):  
Shibing Liu ◽  
Bingen Yang
Keyword(s):  
Optimal Design ◽  
Vibration Analysis ◽  
Oil And Gas ◽  
Waste Treatment ◽  
Dynamic Stiffness ◽  
Modeling And Analysis ◽  
Rotor Systems ◽  
Rotating Systems ◽  
Distributed Transfer Function ◽  
Rubber Bearings

Flexible multistage rotating systems that are supported by water-lubricated rubber bearings (WLRB) have many engineering applications, including power generation, mining, water services, waste treatment, oil and gas industries, and industrial processes. Due to the flexibility of rotating shafts in these applications, dynamic modeling and vibration analysis is essentially important to optimal design and reliable operation of this kind of rotor systems. This paper presents a new model of WLRBs, with the focus on determination of bearing dynamic coefficients. Conventional bearing models are normally of pointwise type, and are invalid for WLRBs that have a large length-to-diameter ratio. The bearing model proposed in this work considers spatially distributed bearing forces, and for the first time, addresses the issue of mixed lubrication, which involves interaction effects of shaft vibration, elastic deformation of rubber material and fluid film pressure. With the bearing model, the dynamic response of a flexible multistage rotating system with WLRBs is described by a Distributed Transfer Function Method (DTFM). The steady-state response of the rotor system due to unbalanced mass is then computed by the DTFM, and compared with experimental data, yielding the dynamic stiffness coefficients of WLRBs. It is shown that the proposed bearing model and DTFM formulation is useful in vibration analysis and optimal design of WLRB-supported flexible multistage rotor systems.

Transient Dynamic Analysis of Rotors Using SMAC Techniques: Part 2, Numerical Study

1992 ◽  
Vol 114 (4) ◽  
pp. 482-488 ◽  
Author(s):  
S. Ratan ◽  
J. Rodriguez
Keyword(s):  
Numerical Study ◽  
Time Domain Analysis ◽  
Superposition Method ◽  
Step Size ◽  
Time Step ◽  
Transient Dynamic Analysis ◽  
Transient Time ◽  
Rotor Systems ◽  
Time Step Size ◽  
And Performance

A new method for performing transient time-domain analysis of rotor systems using a Successive Merging and Condensation (SMAC) technique was introduced in Part 1. This approach can be applied to rotor analysis problems formulated with the finite element method. A numerical study, including examples, comparison of methods, and performance evaluation, is presented here. Validation and applicability of the SMAC method are illustrated with three examples: conservative, nonconservative, and nonlinear. The SMAC algorithm is then compared to the following methods: Transfer Matrix Method (TMM), Modal Superposition Method, and Runge-Kutta Method, and is demonstrated to be computationally more efficient in terms of CPU time and storage space. The issues of stability and time-step size are also studied.

scholarly journals Friction-induced vibration considering multiple types of nonlinearities

2020 ◽  
Vol 102 (4) ◽  
pp. 2057-2075
Author(s):  
Ningyu Liu ◽  
Huajiang Ouyang
Keyword(s):  
Steady State ◽  
Linear Stability ◽  
Numerical Study ◽  
Contact Stiffness ◽  
Geometrical Nonlinearity ◽  
Stick Slip ◽  
Excited Vibration ◽  
Steady State Responses ◽  
State Responses ◽  
Friction Induced Vibration

AbstractThe friction-induced vibration of a novel 5-DoF (degree-of-freedom) mass-on-oscillating-belt model considering multiple types of nonlinearities is studied. The first type of nonlinearity in the system is the nonlinear contact stiffness, the second is the non-smooth behaviour including stick, slip and separation, and the third is the geometrical nonlinearity brought about by the moving-load feature of the mass slider on the rigid belt. Both the linear stability of the system and the nonlinear steady-state responses are investigated, and rich dynamic behaviours of the system are revealed. The results of numerical study indicate the necessity of the transient dynamic analysis in the study of friction-induced-vibration problems as the linear stability analysis fails to detect the occurrence of self-excited vibration when two stable solutions coexist in the system. The bifurcation behaviour of the steady-state responses of the system versus some parameters is determined. Additionally, the significant effects of each type of nonlinearity on the linear stability and nonlinear steady-state responses of the system are discovered, which underlie the necessity to take multiple types of nonlinearities into account in the research of friction-induced vibration and noise.

Distributed Transfer Function Synthesis of Multi-Body Flexible Rotor Systems

1997 ◽  
Author(s):  
Bingen Yang ◽  
Houfei Fang
Keyword(s):  
Transfer Function ◽  
Analytical Solutions ◽  
General Boundary Conditions ◽  
Flexible Rotor ◽  
Modeling And Analysis ◽  
Numerical Examples ◽  
Rotor Systems ◽  
Distributed Transfer Function ◽  
Multi Body ◽  
Flexible Rotor Systems

Abstract A distributed transfer function synthesis is proposed for modeling and analysis of rotor systems assembled from multiple flexible and rigid components. The method is capable of treating non-self-adjoint effects, general boundary conditions and multi-body coupling, and delivers exact and closed-form analytical solutions for various problems. The proposed method is illustrated in two numerical examples.

Progress and Prospects in Translating Nanobiotechnology in Medical Theranostics

2020 ◽  
Vol 16 (5) ◽  
pp. 685-707 ◽  
Author(s):  
Amna Batool ◽  
Farid Menaa ◽  
Bushra Uzair ◽  
Barkat Ali Khan ◽  
Bouzid Menaa
Keyword(s):  
Biological Properties ◽  
Chemical Characteristics ◽  
Intrinsic Properties ◽  
The Past ◽  
Profound Influence ◽  
Functionalized Nanomaterials ◽  
Physico Chemical ◽  
Properties Of Materials ◽  
Targeted Drug ◽  
And Performance

: The pace at which nanotheranostic technology for human disease is evolving has accelerated exponentially over the past five years. Nanotechnology is committed to utilizing the intrinsic properties of materials and structures at submicroscopic-scale measures. Indeed, there is generally a profound influence of reducing physical dimensions of particulates and devices on their physico-chemical characteristics, biological properties, and performance. The exploration of nature’s components to work effectively as nanoscaffolds or nanodevices represents a tremendous and growing interest in medicine for various applications (e.g., biosensing, tunable control and targeted drug release, tissue engineering). Several nanotheranostic approaches (i.e., diagnostic plus therapeutic using nanoscale) conferring unique features are constantly progressing and overcoming all the limitations of conventional medicines including specificity, efficacy, solubility, sensitivity, biodegradability, biocompatibility, stability, interactions at subcellular levels. : This review introduces two major aspects of nanotechnology as an innovative and challenging theranostic strategy or solution: (i) the most intriguing (bare and functionalized) nanomaterials with their respective advantages and drawbacks; (ii) the current and promising multifunctional “smart” nanodevices.

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