نتایج جستجو برای: dynamic and vibration
تعداد نتایج: 16907648 فیلتر نتایج به سال:
Traditionally, application of ultrasound imaging on vocal fold vibration has been limited by the frame rate of dynamic sonography. When the frame rate fs is lower than half of the vibration frequency, ambiguity in the vibration frequency evident from dynamic sonography occurs. This ambiguity is known as aliasing. We exploited the aliasing effect in dynamic 2D-mode sonography to capture the vibr...
The trend toward higher speed, higher power density liquid turbomachinery has inevitably increased the potential for fluid/structure interaction problems, and the severity of those problems. Fluid structure interaction phenomena can lead to increased wear and to structure failure. There are many factors affecting hydraulic and dynamic performance of pumping plants. These factors contribute to d...
In conventional power plants trash-racks are provided at the intakes to protect the turbines. In pumped storage plants, the draft tube or tailrace must also have trash-racks to protect the units while pumping. Because the loads believed to cause many failures of trash-racks are dynamic in nature, it is important to understand the dynamic characteristics of trash-rack structures in general and a...
This paper investigates the coupled axial-radial (CAR) vibration of single-walled carbon nanotubes (SWCNTs) based on doublet mechanics (DM) with a scale parameter. Two coupled forth order partial differential equations that govern the CAR vibration of SWCNTs are derived. It is the first time that DM is used to model the CAR vibration of SWCNTs. To obtain the natural frequency and dynamic respon...
Stewart platform is a good candidate for high speed and six degree of freedom motion control, finding its application in the area of multi-axis vibration control. The critical problems associated with Stewart platform are the high non-linearity and uncertainty in its dynamics. To model the system dynamics of the Stewart platform a simple linear model is developed, for the motion of the Stewart ...
The evaluation and control of the trains induced vibrations needs even more attention in the case of underground tracks which passes near to monuments and historical sites. The rail corrugations which occur due to the wheels’ impulse loads during the operation period of underground railway tracks, usually amplify the ground borne noise and vibration. In the current study, the mentioned phenomen...
the application of e-learning systems - as one of the solutions to the issue of anywhere and anytime learning – is increasingly spreading in the area of education. content management - one of the most important parts of any e-learning system- is in the concern of tutors and teachers through which they can obtain means and paths to achieve the goals of the course and learning objectives. e-learn...
In this paper, transverse and longitudinal vibration of nonlinear plate under exciting of orbiting mass is considered based on first-order shear deformation theory. The nonlinear governing equation of motion are discretized by the finite element method in combination with Newmark’s time integration scheme under von Karman strain-displacement assumptions. For validation of method and formulation...
This study analyzes the free vibration, forced vibration, resonance, and stress wave propagation of orthotropic sandwich plates made of functionally graded materials (FGMs). Dynamic analyses are conducted using a mesh-free method based on first-order shear deformation theory and the shape functions constructed using moving least squares approximation. The sandwich plates are rested on a Pastern...
Atomic force microscope (AFM) has been developed at first for topography imaging; in addition, it is used for characterization of mechanical properties. Most researches have been primarily focused on rectangular single-beam probes to make vibration models simple. Recently, the U-shaped AFM probe is employed to determine sample elastic properties and has been developed to heat samples locally. I...
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