scholarly journals Rotor Dynamic Analysis of Driving Shaft of Dry Screw Vacuum Pump

2019 ◽  
pp. 436-439
Author(s):  
A. Purushotham ◽  
Shravan Kumar
Keyword(s):  
Dynamic Analysis ◽  
Natural Frequencies ◽  
Dynamic Properties ◽  
Vacuum Pump ◽  
Inertia Effects ◽  
Critical Speeds ◽  
Rotor Shaft ◽  
Gyroscopic Moment ◽  
Mass Moment ◽  
Rotor Dynamic

Rotor dynamics is the study of vibration behavior in axially symmetric rotating structures. Devices such as engines, motors, disk drives and turbines all develop characteristic inertia effects that can be analyzed to improve the design and decrease the possibility of failure. At higher rotational speeds, such as in a gas pumps, the inertia effects of the rotating parts must be consistently represented in order to accurately predict the rotor behavior. An important part of the inertia effects is the gyroscopic moment introduced by the precession motion of the vibrating rotor as it spins. As spin velocity increases, the gyroscopic moment acting on the rotor becomes critically significant. Not accounting for these effects at the design level can lead to bearing and/or support structure damage. The main objective of this project is to study the Rotor Dynamic behavior of the drive rotor shaft of the Dry screw vacuum pump. The design of the pump is considered from the one of the reputed pump manufacturing industry. The operational speed of the pump is 4500 rpm, whereas the maximum capable speed of the pump is 10,000 rpm. Rotating machinery produces vibrations depending on the unbalanced mass and gyroscopic effects. Thus an investigation is to be made on the rotor dynamic properties of the shaft to find the natural frequencies and critical speed. For this rotor dynamic analysis was carried out in ANSYS APDL and Workbench16 to find the natural frequencies and critical speeds in the range of 0 to 10000 rpm. Thus an effort is made to shift the mass moment of inertia of the shaft by varying the design of the shaft and to shift the critical frequency to the higher speeds of the shaft there by increasing the efficiency. The modal analysis is performed to find the natural frequencies and it is extended to harmonic analysis to plot the stresses and deflections at the critical speeds. The design of the rotor shaft is made in NX-CAD.

Application of the Riccati Method to Rotor Dynamic Analysis of Long Shafts on a Flexible Foundation

1986 ◽  
Vol 108 (2) ◽  
pp. 177-181 ◽  
Author(s):  
J. W. Lund ◽  
Z. Wang
Keyword(s):  
Dynamic Analysis ◽  
Natural Frequencies ◽  
Impedance Matching ◽  
Critical Speeds ◽  
Unbalance Response ◽  
Flexible Foundation ◽  
Rotor Dynamic

A method is described for calculating critical speeds, unbalance response and damped natural frequencies of long rotors on a flexible foundation. The shaft and the foundation are calculated separately and coupled at the bearings through impedance matching. Included in the analysis is also a method for representing the shaft response by an expansion in its free-free modes.

scholarly journals Dynamic Analysis of the Rod-Fastened Rotor Considering the Characteristics of Circumferential Tie Rods

2021 ◽  
Vol 11 (9) ◽  
pp. 3829
Author(s):  
Haoliang Xu ◽  
Lihua Yang ◽  
Tengfei Xu
Keyword(s):  
Dynamic Analysis ◽  
Natural Frequencies ◽  
Dynamic Performance ◽  
Structural Complexity ◽  
Dynamic Study ◽  
Vibration Equation ◽  
Research Results ◽  
Rotor Shaft ◽  
Tie Rods

The research on the dynamic performance of the rod-fastened rotor (RFR) has always been a hotspot. However, the structural complexity of RFR has brought significant challenges to the dynamic study of the RFR. The tie rods provide preload for the rotor shaft segment, while the coordinate deformation of the tie rods will occur during the process of vibration. In addition, the tie rods and the rotor shaft segments are structurally connected in parallel. These factors all will influence the dynamic performance of the RFR. In this paper, for a RFR system, the vibration equation of the RFR considering all factors of the tie rods is deduced in detail. The influence of various factors on the dynamic performance of the rotor is investigated. Results show that the preload directly affects the dynamic performance of the RFR system. When the preload is small, the tie rod has a larger influence on the natural frequencies of the rotor. However, when the preload force reaches a certain value, the influence of the tie rod on the natural frequencies of the rotor is almost negligible. The research results provide a theoretical reference for the understanding of and further research on RFR.

Critical Speeds of Turbomachinery: Computer Predictions vs. Experimental Measurements—Part II: Effect of Tilt-Pad Bearings and Foundation Dynamics

1987 ◽  
Vol 109 (1) ◽  
pp. 8-14 ◽  
Author(s):  
J. M. Vance ◽  
B. T. Murphy ◽  
H. A. Tripp
Keyword(s):  
Critical Speed ◽  
Natural Frequencies ◽  
State Of The Art ◽  
Dynamic Properties ◽  
Experimental Measurements ◽  
Critical Speeds ◽  
Damping Coefficients ◽  
Speed Prediction ◽  
Bearing Stiffness ◽  
Stiffness And Damping

This is the second of two papers describing results of a research project directed at verifying computer programs used to calculate critical speeds of turbomachinery. This part describes measurements made to determine the characteristics of tilt-pad bearings and foundation dynamics. Critical speeds of a 166 kg laboratory rotor on tilt-pad bearings are then compared with predictions from a state-of-the-art damped eigenvalue computer program. Measured natural frequencies of a steam turbine are also compared with computer predictions. Accuracy of critical speed prediction is shown to depend on accuracy of 1) the “free-free” rotor models, 2) the bearing stiffness and damping coefficients, and 3) the dynamic properties of the foundation, which can be represented by an impedance that must be determined by experimental measurements.

scholarly journals Rotor Dynamic Synchronous Response: A More Thorough Treatment

1993 ◽  
Author(s):  
R. N. Headifen
Keyword(s):  
Steady State ◽  
Dynamic Analysis ◽  
Transient Analysis ◽  
Critical Speeds ◽  
Speed Range ◽  
Wide Speed Range ◽  
Rotor Dynamic

Synchronous response can be a very valuable tool for rotor dynamic analysis. It allows the user to determine rotor displacements over a wide speed range without having to perform a transient analysis at every speed increment. The method is typically used to calculate steady state displacements caused by a rotating imbalance force and the location of critical speeds. While the algorithm presented to perform linear synchronous response is straight forward, there are several modifications that can be made to provide the analyst more useful information.

Dynamic Characteristics Analysis of the Mud Transfer Pump Rotor

2013 ◽  
Vol 455 ◽  
pp. 248-252
Author(s):  
Jun Yuan Sun ◽  
Ji Ming Xiao
Keyword(s):  
Dynamic Analysis ◽  
Modal Analysis ◽  
Dynamic Characteristics ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Dam Construction ◽  
Pump Rotor ◽  
Characteristics Analysis ◽  
Rotor Dynamic ◽  
Dynamic Characteristics Analysis

The mud pump damming technology is a new idea put forward for realization of mechanization and automation of warping dam construction. A mud pump damming machine is studied, the FEM of the mud transfer pump rotor is built, modal analysis and rotor-dynamic analysis are carried out, natural frequencies and mode shapes under different constraints are obtained and the critical speeds of the pump rotor are determined, which will provide reference to improve the running reliability of the mud transfer pump rotor.

Critical Speeds of Geared Rotors by Including Mesh Stiffness and Using a Continuous System Model

1990 ◽  
Author(s):  
O. Sedat Sener ◽  
H. Nevzat Ozguven
Keyword(s):  
Dynamic Analysis ◽  
High Speed ◽  
Natural Frequencies ◽  
Continuous System ◽  
Transmission Error ◽  
System Model ◽  
Graphical Form ◽  
Critical Speeds ◽  
Gear Mesh ◽  
Dynamic Factors

Abstract Dynamic analysis of high speed gearing for the computation of critical speeds and dynamic factors is a must in a proper design, while some other dynamic characteristics of the system such as dynamic transmission error are to be determined for more critical designs. Numerous different models have been suggested for the dynamic analysis of geared systems. These models differ both in the effects included and in the basic assumptions made. A continuous system model is used in this analysis in order to determine the torsional natural frequencies of a gear shaft system composed of two gears, two shafts and two inertias representing the drive and the load. Gear mesh is modelled as a spring connected between two gears. The natural frequencies of the same system are also calculated by using a four degree of freedom classical discrete model in which shaft masses are ignored. The percentage differences in the natural frequencies calculated with the discrete and continuous system models are determined for several values of some nondimensional system parameters. The results are presented in graphical form in terms of the nondimensional parameters defined. Some conclusions which may be important for designers are drawn.

scholarly journals KARAKTERISTIK DINAMIK ROTOR BOW THRUSTER 250 KW MENGGUNAKAN PEMODELAN EULER-BERNOULLI BEAM

2019 ◽  
Vol 13 (1) ◽  
pp. 1-8
Author(s):  
Harry Purnama ◽  
Budi Noviantoro Fadjrin ◽  
Muhammad Ilham Adynugraha ◽  
Cuk Supriyadi Ali Nandar
Keyword(s):  
Dynamic Analysis ◽  
Mode Shape ◽  
Critical Speed ◽  
Dynamic Properties ◽  
Electric Machines ◽  
Mode Shapes ◽  
Bernoulli Beam ◽  
Speed Mode ◽  
Euler Bernoulli Beam ◽  
Rotor Dynamic

Abstrak Perkembangan mesin-mesin elektrik terutama Bow Thruster bagi sektor kemaritiman sangat signifikan. Dari beberapa komponen penting dalam Bow Thruster, rotor terutama poros dan bantalan bearing mempunyai peran penting sehingga  perlu dilakukan analisa. Analisa dinamik merupakan analisa untuk mengetahui sifat-sifat dinamik rotor akibat pengaruh putaran terhadap frekuensi pribadi. Pada makalah ini analisa dinamik dikembangkan dengan pemodelan rotor menggunakan Euler-Bernoulli Beam (EBB). Hasil dari analisa dinamik rotor ini menunjukan putaran kritis dan modus getar dari rotor Bow Thruster. Kata kunci : Rotordinamik, Euler-Bernoilli Beam, Poros, Putaran Kritis, Modus Getar. AbstractThe development of electric machines, especially Bow Thruster, for the maritime sector is significantly increased. The several important components in Bow Thruster, rotors, especially shaft and bearings, have an important role to analyzed. Dynamic analysis is an analysis to determine the dynamic properties of rotors due to the effect of rotation on natural frequency. In this paper a dynamic analysis, rotor modeling was developed using Euler-Bernoulli Beam (EBB). The results of this rotor dynamic analysis show the critical speed and mode shapes of the Bow Thruster rotor. Key Words : Rotor Dynamic, Euler-Bernoulli Beam, Shaft, Critical Speed, Mode Shape.

Coupling Technique of Rotor-Fuselage Dynamic Analysis

1984 ◽  
Vol 106 (2) ◽  
pp. 235-238 ◽  
Author(s):  
D. M. Tang ◽  
M. Q. Wang
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Characteristics ◽  
Dynamic Properties ◽  
Dynamic Stiffness ◽  
Rotor Blades ◽  
Helicopter Rotor ◽  
Coupling Technique ◽  
Rotor Shaft ◽  
Reinforced Plastics ◽  
Natural Dynamic

In this paper is introduced a method of dynamic analysis of the helicopter rotor coupled with fuselage in the rotating plane. The method has been used to determine the inplane rotor-fuselage dynamic properties of a light helicopter with fiberglass-reinforced plastics rotor blades. This paper makes particular reference to the effect of anisotropic dynamic stiffness of the rotor shaft end of fuselage on the natural dynamic characteristics.

Vibration of Flexibly Mounted Gyroscopes

1973 ◽  
Vol 15 (3) ◽  
pp. 225-231
Author(s):  
L. Maunder
Keyword(s):  
Natural Frequencies ◽  
Critical Speeds ◽  
Supporting Structure ◽  
Vibrational Characteristics

Flexibility in the supporting structure of two-axis or single-axis gyroscopes is shown to have a radical effect on vibrational characteristics. The analysis determines the ensuing natural frequencies and critical speeds.

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