Analysis of a High-Speed Flexible Four-Bar Linkage: Part II—Analytical and Experimental Results on the Apollo

1989 ◽  
Vol 111 (1) ◽  
pp. 42-47 ◽  
Author(s):  
F. W. Liou ◽  
A. G. Erdman
Keyword(s):  
High Speed ◽  
Equations Of Motion ◽  
Computer Code ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Stress And Strain ◽  
High Speed Photography ◽  
Mechanism Analysis ◽  
Element Analysis ◽  
Virtual Displacement

By using the equations of motion derived from the virtual displacement [1], a general finite element analysis computer code FEMAP (Four-bar Elastic Mechanism Analysis Program) for the planar motion is developed on the Apollo computer. The output of this program includes the following analysis for any point in the mechanism: velocity, acceleration, natural frequency, displacement, stress and strain. The displacement, stress and strain can be either quasi-static or full vibration analysis. The animation of the entire motion of the flexible linkage can be displayed on the screen. Analytical results are compared with results from a new experimental method which combines high-speed photography with a digital image processing technique.

Analysis of a High-Speed Flexible Four-Bar Linkage: Part I—Formulation and Solution

1989 ◽  
Vol 111 (1) ◽  
pp. 35-41 ◽  
Author(s):  
F. W. Liou ◽  
A. G. Erdman
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Equations Of Motion ◽  
Computer Code ◽  
Element Analysis ◽  
Virtual Displacement ◽  
Axial Forces ◽  
Direct Integration Method ◽  
Analysis Computer ◽  
Four Bar Linkage

Derived from the principle of virtual displacement, a general finite element analysis computer code (FEMAP) of the flexible four-bar linkage is developed on the Apollo computer. In this part, virtual displacement method is presented as a basic theory for the general formulation of the equations of motion. Based on these results, a general finite element computer code of planar four-bar linkage is developed. All the links of the mechanism are considered to be flexible. The nonlinear terms such as coupling between the rigid body and elastic deformation terms and the effect of the axial forces are included. The Newmark direct integration method is used as solution scheme.

Hydrodynamic Study of Bubbles in a Bubble Column Reactor Part I – Image Processing

2015 ◽  
Vol 813-814 ◽  
pp. 1018-1022
Author(s):  
S. Naveen ◽  
T. Sriram ◽  
S. Prithvi Raj ◽  
M. Venkatesan
Keyword(s):  
Image Processing ◽  
High Speed ◽  
Bubble Column ◽  
Waste Water Treatment ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Bubble Column Reactor ◽  
Hydrodynamic Characteristics ◽  
High Speed Photography ◽  
Stationary Liquid Phase

The study of bubble column reactors has its significance in applications such as multiphase reactors, aerators and in industrial waste-water treatment. Extensive works has been done in studying the hydrodynamics of a single gas bubble flowing through stationary liquid phase. The natural breakup of bubble during its motion has been studied in the past. In the Part I of the present work, hydrodynamics of an air bubble after its artificial splitting using a stainless steel mesh is experimentally studied using image processing and high speed photography. The significance of bubble splitting is that it increases the surface area of contact between stationery and moving fluid which in turn increases the rate of reaction desired during the process. The motion of the bubble is captured during its release and after splitting using High-Speed Camera. The velocity, area and diameter of the bubble before and after splitting are calculated by applying Image processing technique on the high speed photograph. The splitting of the bubble is found to vary with the superficial gaseous velocity. The splitting of bubbles into two bubbles of nearly equal size is considered and its hydrodynamic characteristics are studied.

The Application of PIV in the Study of Impeller-Diffuser Interaction in Centrifugal Fan: Part I — Impeller-Vaneless Diffuser Interaction

2001 ◽  
Author(s):  
Tarek Mekhail ◽  
Zhang Li ◽  
Du Zhaohui ◽  
Willem Jansen ◽  
Chen Hanping
Keyword(s):  
Flow Field ◽  
Flow Rate ◽  
High Speed ◽  
Maximum Flow ◽  
Image Processing Technique ◽  
High Speed Photography ◽  
Centrifugal Fan ◽  
Performance Measurements ◽  
Vaneless Diffuser ◽  
Unstable Flow

Abstract The PIV (Particle Image Velocimetry) technology is a brand-new technique of measuring velocity. It started in the 1980’s with the development of high-speed photography and the image processing technique of computers. This article deals with PIV applied to the study of unsteady impeller-vaneless diffuser interaction in centrifugal fen. Experiments were carried out at The Turbomachinery Laboratory of Shanghai Jiaotong University. The test rig consists of a centrifugal, shrouded impeller, diffuser and volute casing all made of plexiglass. A series of performance measurements were carried out at different speeds and different vaneless diffuser widths. PIV measurements were applied to measure the unsteady flow at the exit part of the impeller and the inlet part of the diffuser for the case of the same width vaneless diffuser. The absolute flow field is measured at medium flow rate and at maximum flow rate. It is informative to capture the whole flow field at the same instant of time, and it might be more revealing to observe the unstable flow in real time.

Design and Manufacturing of a Constant Volume Test Combustion Chamber for Jet and Flame Visualization of CNG Direct Injection

2012 ◽  
Vol 217-219 ◽  
pp. 2539-2545 ◽  
Author(s):  
Alireza Hajialimohammadi ◽  
Saeed Ahmadisoleymani ◽  
Amir Abdullah ◽  
Omid Asgari ◽  
Foad Rezai
Keyword(s):  
Finite Element ◽  
Combustion Chamber ◽  
High Speed ◽  
Direct Injection ◽  
Constant Volume ◽  
Ease Of Use ◽  
Diagnostic Methods ◽  
High Speed Photography ◽  
Combustion Chambers ◽  
Element Analysis

Constant volume transparent test combustion chambers are extensively used for investigating injection and fuel burning properties of various combustion engines. Their configuration depends on the engine type and the research purpose. Material of components, shape and dimensions of the chamber and its parts, ease of use, accessibility, sealing and safety of the assembly are the parameters needed to be considered in designing the test cell. This paper explains, structural design of a test combustion chamber and its optical windows using finite element analysis of ANSYS 12.0 software for bearing high pressure variations and thermal shocks of combustion. It was designed for conducting CNG direct injection study on direct injection SI CNG engines for maximum design pressure of 100 bars. Optical diagnostic methods and high speed photography through quartz windows are used for the jet and flame developments. Satisfactory test results of the fabricated system proved that the finite element method can successfully be employed for design of such a system.

Computational Estimation of Bubble Gas Velocity for Slug Flow Pattern in Horizontal Pipes Using Image Processing Technique

2012 ◽  
Author(s):  
María T. Valecillos ◽  
Carlos H. Romero ◽  
María A. Márquez ◽  
Sissi D. Vergara
Keyword(s):  
Image Processing ◽  
Flow Pattern ◽  
Slug Flow ◽  
High Speed ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Gas Velocity ◽  
Two Phase ◽  
Horizontal Pipes ◽  
Computational Estimation

Two-phase slug flow pattern is one of the most common flow patterns present in many industries, therefore its study becomes relevant. The aim of this work was to develop an automated computational program to determine the bubble gas velocity associated to gas-liquid two-phase slug flow by using video digital image processing technique. In order to obtain the images for the analysis, experiments were carried out using a pipe bench for air-water two-phase flow. The experimental facility is located in Simon Bolivar University, in Venezuela. The system has three pipes with different internal diameters and can be rotated around its axis and fixed at any inclination angle from horizontal to vertical flow. The tests were run in a horizontal pipeline of 0.03175m of internal pipe diameter and 8m long. For slug flow visualization a high speed camera Kodak Ektapro 4540mx imager was used. The camera was located in an x/D relation corresponding to 249 from the pipe inlet, ensuring the complete development of the flow. The camera allowed a maximum acquisition velocity of 4500 frames per second. The superficial velocity range was 0.16–1.79m/s and 0.16–1.26m/s for air and water, respectively. To summarize, 165 tests were performed and 1320000 images were analyzed with 20 flow rate combinations. The computational application was validated by comparing it with the velocities measured manually over selected images. Results obtained were compared to several correlations such as Bendiksen [1], Cook & Behnia [2] and Wang et al. [3].

Determination of Two-Phase Flow Void Fraction of R600a in a Horizontal Smooth Tube

2012 ◽  
Author(s):  
Özden Ağra ◽  
Hakan Demir ◽  
Ş. Özgür Atayılmaz ◽  
Ahmet Yurtseven ◽  
A. Selim Dalkılıç ◽  
...  
Keyword(s):  
Neural Network ◽  
Void Fraction ◽  
High Speed ◽  
Saturation Temperature ◽  
Horizontal Tube ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Two Phase ◽  
Void Fractions

In this paper, the void fraction of alternative refrigerant R600a flowing inside horizontal tube is determined by means of an experimental technique, well known correlations in the literature and a generalized neural network analysis. The horizontal tube is made from smooth glass tubing of 4 mm inner diameter. The test runs are done at average saturated condensing temperatures between 30 and 40 °C while the average qualities and the mass fluxes are between 0.45–0.91 and 68.5–138.1 kg m-2s-1 respectively. The flow regime determination inside the tube is performed by means of sight glasses placed at the inlet and outlet sections of the test section, used for in-tube condensation tests, virtually. An image processing technique, performed by means of a high speed camera, is used to determine the void fractions of stratified and annular condensing flow of R600a experimentally. The void fractions are determined using relevant measured data together with 11 different void fraction models and correlations reported in the open literature analytically. Artificial neural network (ANN) analysis is developed to determine the void fractions numerically. For this aim, mass flow rate, average vapor quality, saturation temperature, liquid and vapor densities, liquid and vapor dynamic viscosities and surface tension are selected as the input parameters, while the void fraction is selected as the output. Three-layer network is used for predicting the void fraction. The number of the neurons in the hidden layer was determined by a trial and error process evaluating the performance of the network and standard sensitivity analysis. The measured void fraction values are found to be in good agreement with those from ANN analysis and correlations in the literature. It is also seen that the trained network are more predictive on the determination of void fraction than most of the investigated correlations.

scholarly journals Moving Element Analysis of High-Speed Train-Slab Track System Considering Discrete Rail Pads

2020 ◽  
pp. 2150014
Author(s):  
Tuo Lei ◽  
Jian Dai ◽  
Kok Keng Ang ◽  
Kun Li ◽  
Yi Liu
Keyword(s):  
Coordinate System ◽  
High Speed ◽  
Harmonic Wave ◽  
Equations Of Motion ◽  
Moving Frame ◽  
Iteration Algorithm ◽  
Vehicle Speed ◽  
Element Analysis ◽  
Slab Track ◽  
Track System

This paper presents a study of the dynamic behavior of a coupled train-slab track system considering discrete rail pads. The slab track is modeled as a three-layer Timoshenko beam. The study is carried out using the moving element method (MEM). By introducing a convected coordinate system moving at the same speed as the vehicle, the governing equations of motion of the slab track are formulated in a moving frame-of-reference. By adopting Galerkin’s method, the element stiffness, mass and damping matrices of a truncated slab track in the moving coordinate system are derived. The vehicle is modeled as a multi-body with 10 degrees of freedom. The nonlinear Hertz contact model is used to account for the wheel–rail interaction. The Newmark integration method, in conjunction with a global Newton–Raphson iteration algorithm, is employed to solve the nonlinear dynamic equations of motion of the vehicle–track coupled system. The proposed MEM model of the system is validated through comparison with available results in the literature. Further study is then made to investigate the vehicle–track system accounting for track irregularities modeled as short harmonic wave forms. Results showed that irregularities with short wavelengths have a significant effect on wheel–rail contact force and rail acceleration, and the dynamic response of the track structure does not increase monotonously with the increase of the vehicle speed.

Research on Length Measurement of Workpiece Based on Digital Image Processing Technique

2013 ◽  
Vol 655-657 ◽  
pp. 859-867
Author(s):  
Bin Luo ◽  
Wei Liu ◽  
Yun Luo
Keyword(s):  
Image Processing ◽  
Digital Image Processing ◽  
Digital Image ◽  
High Speed ◽  
Vision System ◽  
Measuring Method ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Measuring Accuracy ◽  
Machine Speed

Aiming at the problems such as slow speed and low measuring accuracy existing in measuring length precision of pin parts in mass production, a new approach of high speed and precise measurement is proposed based on the research of the length measuring methods such as parallel laser length measuring method and area array CCD measuring method, etc. Application of (machine vision system and computer measurement & control technology) digital image processing technology can perform automatic high speed measurement and separation of workpiece effectively and accurately. The experimental results show that the machine speed could reach 4-5 pieces/second, with length measuring accuracy of around 10 microns, indicating that the approach proposed in this paper has important practical value.

scholarly journals Fire Detection Using Multi Criteria Image Processing Technique in Video Sequences

2015 ◽  
Vol 16 (1) ◽  
pp. 136
Author(s):  
Behrouz Memarzadeh ◽  
Mohammad Ali Mohammadi
Keyword(s):  
High Speed ◽  
Fire Detection ◽  
Detection Algorithm ◽  
Processing Technique ◽  
Video Data ◽  
Image Processing Technique ◽  
Video Sequences ◽  
False Alarms ◽  
Surveillance Systems ◽  
Gray Level

Vision-based flame detection has drawn significant attention in the past decade with camera surveillance systems becoming ubiquitous. This paper proposes a multi criterion method to detect fire or flames by processing the video data generated by a high speed camera. Since flame images are special class of images, some of the unique features of a flame may be used to identify flame. There are some differences between flame images and other general images. By using these features we are able to detect fire correctly with least false alarm. In this paper we present an algorithm which can detect fire and reduce number of false alarms by counting number of identified pixels. In the algorithm, we preprocess the images to have better results. So first we adjust the gray level of a flame image according to its statistical distribution to have better processing. After that we try to extract fire features in images. First by using color characteristics, the ratio of red to green, we can identify probable fire-like or fire like pixels. Second, to highlight the regions with high gray level contrast at their edges, we use the extended prewitt filter. We use AND operation on two above processing images to remove unrelated pixels, at last by using flicker frequency, the oscillating change in the number of identified pixels over time is transformed into the frequency domain to complete detection algorithm. Simulation proves the algorithm ability to detect fire in different situations in video sequences.

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