Fluid-Dynamic Loading on a Tilted Rectangular Cylinder Near a Solid Wall

2006 ◽  
Author(s):  
Stefano Malavasi ◽  
Emanuele Zappa
Keyword(s):  
Boundary Conditions ◽  
Strouhal Number ◽  
Vortex Shedding ◽  
Solid Wall ◽  
Large Body ◽  
Experimental Results ◽  
Different Boundary Conditions ◽  
Force Coefficients ◽  
Rectangular Cylinder ◽  
The Impact

We investigate the impact of different boundary conditions on the flow field developing around a tilted rectangular cylinder. We are mainly interested in analyzing the changes in force coefficients and in the vortex shedding Strouhal number due to the proximity of the cylinder to a bottom plate (placed at various distances from the cylinder) at different angles of attack. The angle of attack ranges between −30° and +30° and the cylinder elevation above the bottom wall is varied between almost zero and 200 mm. The effects of the different boundary conditions on the vortex shedding phenomenon are investigated by considering the Strouhal number of the vortex shedding as the key controlling parameter. The experimental results mimicking the unbounded conditions (relative large elevation of the cylinder above the solid wall) are in close agreement with those already found in literature. On the contrary, remarkable differences occur when the elevation of the cylinder is decreased. A large body of experimental results is related to the small elevation conditions at different attack angles, where the presence of the wall has a non-negligible effect on the behavior of the force coefficients and Strouhal number of the vortex shedding.

scholarly journals Feature Extraction of Broken Glass Cracks in Road Traffic Accident Site Based on Deep Learning

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Shuai Liang
Keyword(s):  
Feature Extraction ◽  
Boundary Conditions ◽  
Energy Absorption ◽  
Road Traffic Accident ◽  
Traffic Accident ◽  
Road Traffic ◽  
Plate Glass ◽  
Different Boundary Conditions ◽  
The Impact ◽  
Accident Scene

This paper studies the feature extraction and middle-level expression of Convolutional Neural Network (CNN) convolutional layer glass broken and cracked at the scene of road traffic accident. The image pyramid is constructed and used as the input of the CNN model, and the convolutional layer road traffic accident scene glass breakage and crack characteristics at each scale in the pyramid are extracted separately, and then the depth descriptors at different image scales are extracted. In order to improve the discriminative power of the depth descriptor, Hellinger kernel and Principal Component Analysis (PCA) are used to perform nonlinear and linear transformations. Two aggregation strategies based on depth descriptors are proposed to form a global image representation. The classification experiment of the data set shows that Hellinger kernel, PCA transformation, and two aggregation strategies are all conducive to improving the classification accuracy. In addition, the convolutional layer road traffic accident scene glass breaking and crack feature coding can obtain better classification performance than the fully connected layer feature. We conducted dynamic impact tests on plate glass and Polyvinyl Butyral- (PVB-) laminated glass under different boundary conditions and studied the crack propagation and failure process of the glass under different impact speeds. The results show that there are radial cracks and circular cracks on the glass specimens under the impact load; the glass specimens show partial damage under high-speed impact and the characteristics of glass breaking and cracks at the scene of road traffic accidents; the four-frame plate glass is supported by sharp dagger-like fragments. This paper compares the energy absorption of glass specimens under different boundary conditions. The results show that the energy absorption effect of the four-point supporting glass specimen is generally stronger than that of the four-frame supporting glass.

scholarly journals Studies on the Influence of Drying Shrinkage Test Procedure, Specimen Geometry, and Boundary Conditions on Free Shrinkage

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Bruce Menu ◽  
Marc Jolin ◽  
Benoit Bissonnette
Keyword(s):  
Boundary Conditions ◽  
Test Procedure ◽  
Drying Shrinkage ◽  
Experimental Results ◽  
Specimen Geometry ◽  
Ring Test ◽  
Test Results ◽  
Free Shrinkage ◽  
Free Ring ◽  
The Impact

Although considerable progress has been made in enhancing the use and interpretation of free ring shrinkage test, little is known about the impact of the test procedure, the specimen geometry, the surface area-to-volume (S/V) ratio exposed to drying, and the boundary conditions (sealing configuration) on the measured shrinkage. This paper highlights recent findings illustrating the influence of the test procedure, the S/V ratio exposed to drying, the geometry of specimen, and the boundary conditions. A series of experimental results are presented from free shrinkage on ring test specimens to illustrate that the test procedure can significantly influence the measured free shrinkage. A second series of experimental results are presented from specimens with different geometries and S/V ratio exposed to drying to illustrate that drying shrinkage is dependent on both the specimen geometry and the surface exposed to drying. Test results further show that, even for the same S/V ratio exposed to drying, shrinkage is strongly dependent on the specimen’s geometry and boundary conditions.

Low-velocity impact analysis of viscoelastic composite laminated nanoplate based on nonlocal strain gradient theory for different boundary conditions

2020 ◽  
pp. 109963622092507
Author(s):  
Peyman Rashidpour ◽  
Majid Ghadiri ◽  
Asghar Zajkani
Keyword(s):  
Boundary Conditions ◽  
Laminated Composite ◽  
Low Velocity Impact ◽  
Strain Gradient Theory ◽  
Gradient Theory ◽  
Low Velocity ◽  
Velocity Impact ◽  
Different Boundary Conditions ◽  
The Impact ◽  
Nonlocal Strain Gradient

In this paper, the dynamic behavior of the nanoparticle low-velocity impact on viscoelastic laminated composite nanoplate has been investigated. To determine the impact force between nanoparticle and laminated composite nanoplate, the van der Waals interaction force is considered based on the description of Lennard-Jones. The material properties of each layer of laminated composite nanoplate are supposed to be viscoelastic based on the Kelvin–Voigt model. The governing equations of the system are derived based on the first-order shear deformation plate theory and the nonlocal strain gradient theory by employing Hamilton’s principle. Galerkin’s method is employed to solve differential equations of nanoplate with different boundary conditions. Afterward, the system of time-dependent equations is solved by applying the Newmark’s method. The parametric study is presented to examine the effect of particle initial velocity, particle radius, viscoelastic modulus, fiber orientation, nonlocal parameter, length scale parameter, and different boundary conditions on the impact response of nanoplate.

Experiments on the Postbuckling Behavior of Square Plates Loaded in Edge Compression

1961 ◽  
Vol 28 (2) ◽  
pp. 238-244 ◽  
Author(s):  
Noboru Yamaki
Keyword(s):  
Boundary Conditions ◽  
Reasonable Agreement ◽  
Numerical Solutions ◽  
Experimental Results ◽  
Initial Deflection ◽  
Rectangular Plates ◽  
Maximum Deflection ◽  
Postbuckling Behavior ◽  
Different Boundary Conditions

In previous papers [1, 2], the postbuckling behavior of rectangular plates under edge compression has been studied theoretically under eight different boundary conditions, and numerical solutions are presented for square plates with and without initial deflection. To compare with these results, experiments were carried out by using aluminum square plates, and the relations of the maximum deflection, stresses, and strains at typical points in the plate with applied loads were determined under four different boundary conditions. It is found that the experimental results are in reasonable agreement with those theoretically predicted.

Modal Analysis of Woven Fiber Composite Plates with Different Boundary Conditions

2015 ◽  
Vol 15 (01) ◽  
pp. 1540001 ◽  
Author(s):  
Itishree Mishra ◽  
Shishir Kumar Sahu
Keyword(s):  
Boundary Conditions ◽  
Modal Analysis ◽  
Fiber Composite ◽  
Shear Deformation Theory ◽  
Composite Plates ◽  
Experimental Results ◽  
Modal Testing ◽  
Geometrical Parameters ◽  
Different Boundary Conditions ◽  
Numerical Predictions

Most of the work done for the vibration of composite plates published in the literature is either analytical or numerical studies with few experimental results available on composites with unidirectional fibers. The present study involves extensive experimental works to investigate the free vibration of industry driven woven fiber glass/epoxy composite plates with different boundary conditions including free–free cases. The modern modal testing and subsequent analysis with powerful computer and digital analysis system is an important tool for prediction of behavior of structures. The specimens of woven glass fiber and epoxy matrix composite plates are manufactured by the hand-layup technique. Elastic parameters of the plate are also determined experimentally by tensile testing of specimens using INSTRON 1195. An experimental investigation is carried out using modal analysis technique with Fast Fourier Transform Analyzer, PULSE lab shop, impact hammer and contact accelerometer to obtain the frequency response functions. The computational results are compared with results of previous studies in literature wherever available. The experimental results are also compared with the FEM numerical analysis based on first-order shear deformation theory. The effects of different geometrical parameters including number of layers, aspect ratio, fiber orientation and different boundary conditions of woven fiber composite plates are studied in detail. It is observed that comparisons performed between numerical predictions and experimental tests have a good correlation. The natural frequency is very less for cantilever than simply supported and fully clamped boundary conditions. The prediction of dynamic behavior of laminated composite plates plays a significant role in the future applications of structural composites.

The Impact of Cash Mobs in the Vote with the Wallet Game: Experimental Results

2016 ◽  
Author(s):  
Leonardo Becchetti ◽  
Maurizio Fiaschetti ◽  
Francesco Salustri
Keyword(s):  
Experimental Results ◽  
The Impact
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