Acoustically Induced Vibration of Drums Excited by Rotating Machinery

2005 ◽  
Author(s):  
Itsuro Hayashi ◽  
Shijie Guo
Keyword(s):  
Fatigue Failure ◽  
High Frequency ◽  
Three Dimensional ◽  
Rotating Machinery ◽  
Coupled Analysis ◽  
Pressure Loading ◽  
High Frequency Region ◽  
One Dimensional ◽  
Material Fatigue ◽  
High Frequency Vibrations

Rotating machinery generates pressure pulsations, and the pulsations may cause severe vibrations of drums in high frequency region, resulting in material fatigue failure under certain conditions. Experiments and numerical simulations were performed to investigate the mechanism of the high frequency vibrations of the drums downstream of compressors. The results show that fatigue failure occurs when acoustic diametral modes of a drum are excited by pressure loading. In order to establish practical countermeasures against the vibrations, three-dimensional sound-structural coupled analysis as well as one-dimensional pulsation analysis were conducted. As a result, practical measures such as changing diameter, or thickness of the drums, applying restriction orifice are confirmed effective by using the approach proposed in this study. The validity of the simulation methods incorporating the sensitivity to the fluid conditions is shown.

Effects of Meniscus Motion on Ejection Performance in Thermal Inkjet Print Heads by 3-D Numerical Simulation and 1-D Lumped Modeling

2003 ◽  
Author(s):  
Min Soo Kim ◽  
Yong Soo Lee ◽  
Suho Shin ◽  
You-Seop Lee ◽  
Seung Joo Shin ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Material Properties ◽  
High Frequency ◽  
Three Dimensional ◽  
Fast Computation ◽  
Lumped Model ◽  
One Dimensional ◽  
Droplet Ejection ◽  
Printing Quality ◽  
Design Factors

Undesired meniscus motion at the nozzle exti can cause detrimental effects on ejection performance of an inkjet print head, resulting in degradation of printing quality at high frequency operation. In this study, visulization of droplet ejection and meniscus motion was performed experimentally, and the results were compared with those of numerical simulations. Effects of design factors on themeniscus motion, such as material properties of ink and geometric dimensions of head structure, were investigated by three-dimensional (3-D) numerical simulations. The result demonstrated that the ejection performance and the following menicus motion might be affected significantly due to changes in the design factors. For simple and fast computation, one-dimensional (1-D) lumped model was constructed, and its results were meaningful for the intuitive understanding of ejection performance and meniscus oscillation. Also, effects of different meniscus conditions on the subsequent ejection were investigated by 3-D numerical computations. The results showed that a stabilizing time, e.g., 70μs, was needed for uniform reproducible ejection. The results of this study will be helpful for development of the inkjet print heads of higher performance.

scholarly journals On the existence of high-frequency boundary resonances in layered elastic media

2015 ◽  
Vol 471 (2178) ◽  
pp. 20140878 ◽  
Author(s):  
K. D. Cherednichenko ◽  
S. Cooper
Keyword(s):  
Surface Wave ◽  
Boundary Conditions ◽  
High Frequency ◽  
Three Dimensional ◽  
Homogeneous Medium ◽  
Elastic Media ◽  
Displacement Boundary ◽  
Boundary Spectrum ◽  
New Type ◽  
High Frequency Vibrations

We analyse the asymptotic behaviour of high-frequency vibrations of a three-dimensional layered elastic medium occupying the domain Ω =(− a , a ) 3 , a >0. We show that in both cases of stress-free and zero-displacement boundary conditions on the boundary of Ω a version of the boundary spectrum, introduced in Allaire and Conca (1998 J. Math. Pures. Appl. 77, 153–208. ( doi:10.1016/S0021-7824(98)80068-8 )), is non-empty and part of it is located below the Bloch spectrum. For zero-displacement boundary conditions, this yields a new type of surface wave, which is absent in the case of a homogeneous medium.

scholarly journals Research on a Rotating Machinery Fault Prognosis Method Using Three-Dimensional Spatial Representations

2016 ◽  
Vol 2016 ◽  
pp. 1-10
Author(s):  
Xiaoni Dong ◽  
Xiaodong Zhang ◽  
Zaichao Ma ◽  
Guangrui Wen ◽  
Zhifen Zhang
Keyword(s):  
Spatial Representation ◽  
Three Dimensional ◽  
Data Representation ◽  
Rotating Machinery ◽  
Process Models ◽  
Sensor Data ◽  
One Dimensional ◽  
Time Domains ◽  
Fault Prognosis ◽  
Representation Method

Process models and parameters are two critical steps for fault prognosis in the operation of rotating machinery. Due to the requirement for a short and rapid response, it is important to study robust sensor data representation schemes. However, the conventional holospectrum defined by one-dimensional or two-dimensional methods does not sufficiently present this information in both the frequency and time domains. To supply a complete holospectrum model, a new three-dimensional spatial representation method is proposed. This method integrates improved three-dimensional (3D) holospectra and 3D filtered orbits, leading to the integration of radial and axial vibration features in one bearing section. The results from simulation and experimental analysis on a complex compressor show that the proposed method can present the real operational status and clearly reveal early faults, thus demonstrating great potential for condition-based maintenance prediction in industrial machinery.

A gear rattle model accounting for oil squeeze between the meshing gear teeth

2005 ◽  
Vol 219 (9) ◽  
pp. 1075-1083 ◽  
Author(s):  
R Brancati ◽  
E Rocca ◽  
R Russo
Keyword(s):  
High Frequency ◽  
Oil Viscosity ◽  
Damping Force ◽  
Oil Film ◽  
One Dimensional ◽  
Gear Teeth ◽  
High Frequency Vibrations ◽  
The Impact ◽  
Gear Rattle ◽  
Lubrication Conditions

In this paper a non-linear one-degree-of-freedom model for analysis of gear rattle vibrations in automotive manual transmissions is presented. In order to take into account the damping effects owing to the oil in the gap between two teeth of a meshing gear, a simple one-dimensional model for the oil-film squeeze effects is proposed. The squeeze model assumes that the damping force is proportional to the oil viscosity and to the extension of the oil film in the plane of curvature of the teeth, which may depend on the lubrication conditions (dry sump, splash, bath). The results provided from several numerical simulations, carried out with reference to helical involute tooth pairs, confirm the capability of oil in reducing the high-frequency vibrations subsequent to the impact between the teeth. In particular, the influence exerted by oil viscosity and gap extension on the rattle characteristics is investigated through the analysis of the transient response of the driven gear by imposing a harmonic motion to the driving gear.

A Design Methodology for Radial Turbomachinery: Application to Turbines and Compressors

2002 ◽  
Author(s):  
Carlo Cravero
Keyword(s):  
Design Methodology ◽  
Power Plants ◽  
Three Dimensional ◽  
Design Procedure ◽  
Rotating Machinery ◽  
Design Analysis ◽  
Design Tool ◽  
Navier Stokes ◽  
Complementary Information ◽  
One Dimensional

Different design/analysis tools are combined in an automatic procedure for the design of radial turbomachinery. The algorithms developed have different complexity levels ranging from the meanline one-dimensional design tool to the fully three-dimensional Navier-Stokes based analysis. Each code gives complementary information to the designer. The codes have been written and developed by the author at DIMSET. The design procedure is developed for both radial compressors and turbines and it is proposed for the dimensioning of rotating machinery for microgasturbine power plants.

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