scholarly journals Numerical investigation of leakage behaviour in long radius elbows

Water SA ◽  
2020 ◽  
Vol 46 (1 January) ◽  
Author(s):  
Moustafa S Darweesh ◽  
Osama S Hussien
Keyword(s):  
Finite Element Analysis ◽  
Empirical Equation ◽  
Sensitivity Study ◽  
Internal Diameter ◽  
Longitudinal Stress ◽  
Element Analysis ◽  
System Pressure ◽  
Pressure Area ◽  
The Relationship ◽  
Leakage Exponent

This paper focuses on the relationship between leakage opening areas and pressure heads for 90° long radius elbows under elastic limits using finite element analysis (SAP 2000). The results indicate that leakage opening areas grow linearly as the system pressure increases and the relation is described by the pressure–area slope (M). A sensitivity study was performed to show the effect of various parameters on M, as well as the leakage exponent (N). It was found that elbow internal diameter has the largest influence on the pressure–area slope, followed by the modulus of elasticity and finally elbow wall thickness. The longitudinal stress and Poisson’s ratio have a negligible effect on M. Furthermore, leak quantity is related to the pressure raised to a power ranging from 0.495 to 0.592. Regression analysis was used to derive an empirical equation to predict the pressure–area slope of round holes within elbows with different properties.  

Dämpfungsschlitze in Kreissägeblättern*/Parametric FE analysis to identify the mode of action of damping slots in circular saw blades

2015 ◽  
Vol 105 (01-02) ◽  
pp. 41-46
Author(s):  
C. Birenbaum ◽  
U. Heisel ◽  
S. Weiland
Keyword(s):  
Finite Element Analysis ◽  
Thermal Expansion ◽  
Analytical Approach ◽  
Simulation Models ◽  
Fe Analysis ◽  
Element Analysis ◽  
Annular Plates ◽  
Circular Saw ◽  
Characteristic Modes ◽  
The Relationship

In Kreissägeblättern werden zur Verminderung von Schwingungen und zum Ausgleich thermischer Dehnungen sogenannte Dehnungs- und Dämpfungsschlitze eingebracht. Die Wirkungsweise der Schlitze auf die dynamischen Eigenschaften besteht einerseits in der Dämpfungswirkung sowie andererseits in der Modifikation der Schwingungseigenformen. Um Wirkmechanismen und Optimierungsmöglichkeiten zu identifizieren, werden in den hier vorgestellten Untersuchungen mithilfe der Finiten-Elemente-Methode (FEM) Analysen von Kreisscheiben mit einfachen Schlitzkonfigurationen durchgeführt. Hierdurch sollen Zusammenhänge einzelner Schlitzparameter mit den statischen und dynamischen Eigenschaften von Kreissägeblättern aufgezeigt werden. Zur Validierung des entwickelten Simulationsmodells dienen analytische Berechnungen.   To reduce vibrations and adjust for thermal expansion, so-called damping slots and expansion slots are applied to circular saw blades. The slots affect the dynamic behavior of the saw blades by damping the vibration and altering the characteristic modes and frequencies. An FE(Finite Element) analysis of annular plates with simple arrangements of damping and expansion slots is performed to identify the mechanisms and improvement opportunities. This allows determining the relationship between slot parameters and the static and dynamic qualities of circular saw blades. The developed simulation models are validated using an analytical approach.

Research on Deflection Analysis and Compensation Method of Ram of Boring and Milling Machining Center

2014 ◽  
Vol 633-634 ◽  
pp. 693-698
Author(s):  
Long Xin ◽  
Shi Chao Cui ◽  
Qi Lin Shu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Least Squares Method ◽  
Preliminary Calculation ◽  
Element Analysis ◽  
Object A ◽  
Machining Center ◽  
Deflection Analysis ◽  
Long Stroke ◽  
The Relationship

In this paper, the ram of boring and milling machining center is taken as the research object. A new method that hydraulic pull rods compensation is proposed to solve the problem of deformation compensation of long stroke ram of boring and milling machining center. Firstly, the method of finite element analysis is used to get the laws of ram deformation and the relationship curve between the ram deformation and the stroke of ram. Secondly, the preliminary calculation value of pull rods compensation force is derived based on the theoretical analysis of material mechanics. The relationship curve between compensation force and the stroke of ram is obtained by finite element analysis and polynomial least squares method. Finally, the analyzed results are as follows: the laws of ram deformation distribution is accurately predicted by the used method, the deflection error of the ram is well controlled,and the machining precision is significantly improved.

Design, analysis and test of a novel cylinder-driven mode applied to microgripper

2021 ◽  
pp. 1-14
Author(s):  
Xiaodong Chen ◽  
ZM Xie ◽  
Huifeng Tan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Compliant Mechanisms ◽  
Research Field ◽  
Driving Pressure ◽  
Maximum Output ◽  
Element Analysis ◽  
Output Displacement ◽  
Micro Parts ◽  
The Relationship

Abstract How to enlarge the output displacement is a key issue in the research field of microgrippers. It is difficult to further enlarge the output displacement for the traditional displacement transmission mechanism (DTM). In this research, a two-stage amplification cylinder-driven DTM based on the compliant mechanisms is designed to realize the displacement output expansion. The opening and closing of the clamping jaws is driven by the air cylinder to enlarge the output displacement of the microgripper. According to the analysis of statics model of the mechanism, the relationship between the output displacement of the microgripper and the driving pressure of the cylinder is established. The magnification of the microgripper is obtained using a dynamic model. Moreover, based on the finite element analysis, the mechanical structure parameters are optimized. The microgripper was fabricated by utilizing wire electro discharge machining (WEDM) technique, and then a series of experiments were carried out to obtain the relationship between the displacement and the driving pressure. It is found that the maximum output displacement measured is 1190.4μm under the pressure of 0-0.6 Mpa, corresponding to the magnification of 47.63. Compared with the results of finite element analysis and theoretical calculation, the test results have a discrepancy of 2.39% and 6.62%, respectively. The microgripper has successfully grasped a variety of micro-parts with irregular shapes, and parallel grasping can be achieved, demonstrating the potential application of this design in the field of micromanipulation.

Gas Hold-Up Profiles Determination by means of Ultrasonic Transducer

2014 ◽  
Vol 69 (8) ◽  
Author(s):  
Mohd Hafiz Fazalul Rahiman ◽  
Ruzairi Abdul Rahim ◽  
Herlina Abdul Rahim ◽  
Zulkarnay Zakaria ◽  
Muhammad Jaysuman Pusppanathan ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Ultrasonic Transducer ◽  
Liquid Column ◽  
Element Analysis ◽  
Storage Oscilloscope ◽  
Digital Storage ◽  
Digital Storage Oscilloscope ◽  
The Relationship ◽  
Signal Conditioning Circuit ◽  
Conditioning Circuit

This paper details a work carried out to measure gas hold-up profiles in a liquid column using a pair of ultrasonic transducer. The gas hold-up profiles from 1.85 mm to 7.7 mm diameter are of interest in this investigation. The measurement setup consist of ultrasonic transducer, an experimental column, signal conditioning circuit, and a digital storage oscilloscope. The experiment was conducted using several gas hold-up profiles and the relationship between the ultrasonic amplitude and the profile were deduced. A finite element analysis was carried out to further verify the results. This paper explains how one could use ultrasonic transducer to estimate the gas hold-up profiles in a liquid column.

Study on the Reduction Strategy of Machining-Induced Edge Chipping Based on Finite Element Analysis of In-Process Workpiece Structure

2013 ◽  
Vol 135 (1) ◽  
Author(s):  
Hu Gong ◽  
F. Z. Fang ◽  
X. F. Zhang ◽  
Juan Du ◽  
X. T. Hu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Principal Stress ◽  
Maximum Principal Stress ◽  
Machining Process ◽  
Element Analysis ◽  
Edge Chipping ◽  
Additional Support ◽  
The Relationship ◽  
Complex Parts

Edge chipping is one of the most serious issues during machining process of brittle materials. To find an effective method to reduce edge chipping, the relationship between the distribution of maximum principal stress and edge chipping is studied comprehensively based on 3D finite element analysis (FEA) model of in-process workpiece structure in this paper. Three-level influencing factors of edge chipping are proposed, which are helpful to understand the relationship between intuitive machining parameters and edge chipping at different levels. Based on the analysis, several experiments are designed and conducted for drilling and slotting to study the strategy of controlling edge chipping. Two methods are adopted: (a) adding additional support, (b) improving tool path. The result show that edge chipping can be reduced effectively by optimizing the distribution of the maximum principal stress during the machining process. Further, adding addtitional support method is extended to more complex parts and also obtain a good result. Finally, how to use adding additional support method, especially for complex parts, will be discussed in detail. Several open questions are raised for future research.

Longitudinal Stress Analysis of Local Compression on the Center of Plain Concrete Column

2014 ◽  
Vol 578-579 ◽  
pp. 71-74 ◽  
Author(s):  
Yan Wang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Analysis ◽  
Plain Concrete ◽  
Area Ratio ◽  
Concrete Column ◽  
Longitudinal Stress ◽  
Element Analysis ◽  
Compression Area

Taking local compression on the center of plain concrete square column as an example, by using finite element analysis found that longitudinal stressdistribution and size of local compression on the center of plain concrete square column related to local compression acting position and local compression area ratio.

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