Effect of Substrate Flexibility on the Pressure Distribution and Lifting Force Generated by a Bernoulli Gripper

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
X. Brun ◽  
S. N. Melkote
Keyword(s):  
Pressure Distribution ◽  
Radial Pressure ◽  
Silicon Wafers ◽  
Cfd Modeling ◽  
Element Analysis ◽  
Modeling And Analysis ◽  
Lifting Force ◽  
Computational Fluid Dynamics Cfd ◽  
Thin Silicon ◽  
Good Agreement

This paper presents the modeling and analysis of the pressure distribution and lifting force generated by a Bernoulli gripper when handling flexible substrates such as thin silicon wafers. A Bernoulli gripper is essentially a radial airflow nozzle used to handle large and small, rigid and nonrigid materials by creating a low pressure region or vacuum between the gripper and material. Previous studies on Bernoulli gripping have analyzed the pressure distribution and lifting force for handling thick substrates that undergo negligible deformation. Since the lifting force produced by the gripper is a function of the gap between the handled object and the gripper, any deformation of the substrate will influence the gap and consequently the pressure distribution and lifting force. In this paper, the effect of substrate (thin silicon wafer) flexibility on the equilibrium wafer deformation, radial pressure distribution and lifting force is modeled and analyzed using a combination of computational fluid dynamics (CFD) modeling and finite element analysis. The equilibrium wafer deformation for different air flow rates is compared with experimental data and is shown to be in good agreement. In addition, the effect of wafer deformation on the pressure and lifting force are shown to be significant at higher volumetric airflow rates. The modeling and analysis approach presented in this paper is particularly useful for evaluating the effect of gripper variables on the handling stresses generated in thin silicon wafers and for gripper design optimization.

Thermo-Mechanical Modeling and Analysis of Equal Channel Angular Pressing

2005 ◽  
Vol 23 ◽  
pp. 263-266 ◽  
Author(s):  
Qing Xiang Pei ◽  
B.H. Hu ◽  
C. Lu
Keyword(s):  
Equal Channel Angular Pressing ◽  
Temperature Rise ◽  
Flow Behavior ◽  
Material Model ◽  
Workpiece Material ◽  
Element Analysis ◽  
Modeling And Analysis ◽  
Die Geometry ◽  
Angular Pressing ◽  
Good Agreement

Thermo-mechanical finite element analysis was carried out to study the deformation behavior and temperature distribution during equal channel angular pressing (ECAP). The material model used is the Johnson-Cook constitution model that can consider the multiplication effect of strain, strain rate, and temperature on the flow stress. The effects of pressing speed, pressing temperature, workpiece material and die geometry on the temperature rise and flow behavior during ECAP process were investigated. The simulated temperature rise due to deformation heating was compared with published experimental results and a good agreement was obtained. Among the various die geometries studied, the two-turn die with 0° round corner generates the highest and most uniform plastic strain in the workpiece.

scholarly journals Characterization of an aerodynamic lens for transmitting particles greater than 1 micrometer in diameter into the Aerodyne aerosol mass spectrometer

2013 ◽  
Vol 6 (11) ◽  
pp. 3271-3280 ◽  
Author(s):  
L. R. Williams ◽  
L. A. Gonzalez ◽  
J. Peck ◽  
D. Trimborn ◽  
J. McInnis ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
Transmission Efficiency ◽  
Cfd Modeling ◽  
Operating Pressure ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Valve Assembly ◽  
Computational Fluid Dynamics Cfd ◽  
Good Agreement

Abstract. We have designed and characterized a new inlet and aerodynamic lens for the Aerodyne aerosol mass spectrometer (AMS) that transmits particles between 80 nm and more than 3 μm in vacuum aerodynamic diameter. The design of the inlet and lens was optimized with computational fluid dynamics (CFD) modeling of particle trajectories. Major changes include a redesigned critical orifice holder and valve assembly, addition of a relaxation chamber behind the critical orifice, and a higher lens operating pressure. The transmission efficiency of the new inlet and lens was characterized experimentally with size-selected particles. Experimental measurements are in good agreement with the calculated transmission efficiency.

Simulation of Circular Tubes Fitted with V Cut and Square Cut Rotors

2013 ◽  
Vol 561 ◽  
pp. 547-552
Author(s):  
Peng Jiang ◽  
Hua Yan ◽  
Zhen Zhang ◽  
Yu Mei Ding ◽  
Wei Min Yang
Keyword(s):  
Heat Transfer ◽  
Thermal Performance ◽  
Turbulent Heat Transfer ◽  
Cfd Modeling ◽  
Turbulent Heat ◽  
Circular Tubes ◽  
Performance Factor ◽  
Thermal Performance Factor ◽  
Computational Fluid Dynamics Cfd ◽  
Good Agreement

This work presents the effect of V cut and square cut rotors in circular tubes for turbulent heat transfer using computational fluid dynamics (CFD) modeling. The computational results are in good agreement with experimental data. The obtained results reveal that the use of square cut rotors leads to higher Nusselt number than use of V cut rotors. The results also show that the heat transfer rate, friction factor and thermal performance factor of rotors with square cut increase with the increase of width (a) and depth (b) of rotors’ cut. Square cut rotors with a=b=3 yields higher mean thermal performance factor than those with other width and depth, a=b=1, 2 and the highest thermal performance factor of square cut rotors at a=b=1, 2, 3 are found to be 2.08, 2.11 and 2.13.

Interaction Between Advanced Spar and Regular Waves

2017 ◽  
Author(s):  
Shingo Yamanaka ◽  
Takayuki Hirai ◽  
Yasunori Nihei ◽  
Akira Sou
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Pressure Distribution ◽  
Simulation Experiment ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Regular Waves ◽  
Experimental Database ◽  
Computational Fluid Dynamics Cfd ◽  
Good Agreement

Advanced spar type of the floating wind turbine with a short spar and a cylindrical column floater has been developed and tested recently. However, numerical methods to accurately simulate the interaction between the advanced spar and waves have not been established yet. In this study we simulated the free surface flow around an advanced spar in regular waves using open source computational fluid dynamics (CFD) software OpenFOAM to examine its applicability. We used olaFOAM which equipped with the functions to set the boundary conditions of wave generation at the inlet and wave absorption at the exit. An experiment of the advanced spar model fixed in space in the regular waves with various wave periods was also conducted to obtain an experimental database on the horizontal and vertical forces acting on the structure and pressure distribution on the floater surface. The results of the forces obtained by the numerical simulation, experiment, Morison’s equation were compared to examine the validity of the numerical model. Numerical and experimental results of the horizontal and vertical forces as well as pressure distribution on the floater surface were in good agreement, which confirmed the validity of the present numerical method. Then, we evaluated numerically the effects of the edge of the column by simulating a sharp-edged and a chamfered column floater. The result clarified that a chamfered edge decreased the wake which reduced the forces acting on the floater structure.

Lateral-Directional Aerodynamics of a Canard Guided Spin Stabilized Projectile at Supersonic Velocity

2011 ◽  
Vol 110-116 ◽  
pp. 4343-4350 ◽  
Author(s):  
Xiu Ling Ji ◽  
Hai Peng Wang ◽  
Shi Ming Zeng ◽  
Chen Yang Jia
Keyword(s):  
Computational Study ◽  
Cfd Modeling ◽  
Aerodynamic Coefficients ◽  
Force Coefficient ◽  
Modeling And Analysis ◽  
Moment Coefficient ◽  
Computational Fluid Dynamics Cfd ◽  
Spinning Projectile ◽  
Yaw Moment ◽  
Side Force Coefficient

A computational study performed for a canard guided spin stabilized projectile using finite volume TVD schemes is described in this paper. Computational Fluid Dynamics (CFD) modeling and analysis of the spinning projectile with fixed canard are conducted to determine the lateral-directional aerodynamic coefficients at three supersonic speeds and various angles of attack. The analyses provide a detailed understanding of the effects of canard with different circumferential position on lateral-directional aerodynamic coefficients, and the results show that side force coefficient and yaw moment coefficient vary periodically with the circumferential position angles of canard.

scholarly journals CFD modeling of 2D impact with symmetric entry

2011 ◽  
Vol 4 (8) ◽  
pp. 25
Author(s):  
Roberto Algarín ◽  
Antonio Bula ◽  
Oscar Tascón
Keyword(s):  
Pressure Distribution ◽  
Vertical Velocity ◽  
Cfd Modeling ◽  
Calm Water ◽  
Good Agreement

The 2D impact phenomenon in calm water, considering symmetric entry with vertical velocity is studied. The analysis was performed by using commercial STAR-CCM+ computational fuid dynamics software. Thee results obtained from the simulations are pressure distribution and force during impact. The study was carried out for typical planning of boat sections. The results are compared with models and data obtained from some authors and they present very good agreement.

scholarly journals Characterization of an aerodynamic lens for transmitting particles > 1 micrometer in diameter into the Aerodyne aerosol mass spectrometer

2013 ◽  
Vol 6 (3) ◽  
pp. 5033-5063 ◽  
Author(s):  
L. R. Williams ◽  
L. A. Gonzalez ◽  
J. Peck ◽  
D. Trimborn ◽  
J. McInnis ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
Transmission Efficiency ◽  
Cfd Modeling ◽  
Operating Pressure ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Valve Assembly ◽  
Computational Fluid Dynamics Cfd ◽  
Good Agreement

Abstract. We have designed and characterized a new inlet and aerodynamic lens for the Aerodyne aerosol mass spectrometer (AMS) that transmits particles between 80 nm and more than 3 μm in diameter. The design of the inlet and lens was optimized with computational fluid dynamics (CFD) modeling of particle trajectories. Major changes include a redesigned critical orifice holder and valve assembly, addition of a relaxation chamber behind the critical orifice, and a higher lens operating pressure. The transmission efficiency of the new inlet and lens was characterized experimentally with size-selected particles. Experimental measurements are in good agreement with the calculated transmission efficiency.

scholarly journals Modeling and Mitigation of Acoustic Induced Vibration (AIV) in Piping Systems

2018 ◽  
Author(s):  
Brandon L. Ridens ◽  
Timothy C. Allison ◽  
Sarah B. Simons ◽  
Klaus Brun
Keyword(s):  
Dynamic Pressure ◽  
Pressure Fluctuations ◽  
Mitigation Strategies ◽  
Cfd Modeling ◽  
Screening Methods ◽  
Element Analysis ◽  
Modeling And Analysis ◽  
Pressure Transducers ◽  
Piping Systems ◽  
The Impact

This paper explores new analysis techniques and mitigation concepts developed to extend the current state of the art acoustic induced vibrations (AIV) analyses. These new methods are intended to provide more accurate evaluations of this phenomenon in an attempt to solve AIV problems found in blowdown and piping systems. Current screening methods for AIV are based on pass/fail data with minimal or undesired options for reducing the likelihood of failure for AIV events. Computational fluid dynamics simulations and finite element analysis in combination with lab testing of novel mitigation options using accelerometers, dynamic pressure transducers, and strain gages were performed to better understand the phenomenon and develop possible solutions to reduce the impact of AIV on piping systems. Results of the testing and analyses performed at the Southwest Research Institute (SwRI) indicate that there is a possible correlation with acoustic modes, structural modes, and elevated stresses during AIV events. Minor reductions in dynamic pressure fluctuations throughout piping during AIV events can be made by changes in valve geometry and piping configurations. Results of CFD modeling and analysis demonstrate that computational analysis can be used to evaluate mitigation strategies and suggest that the use of a dampener as a mitigation technique may be successful in reducing the amplitudes of dynamic pressure waves in piping systems caused by AIV events.

Simulation Models Predicting Pressure Distribution and Transmission Underneath Blood Pressure Cuffs of Different Types

2020 ◽  
Vol 7 (5) ◽  
pp. 38-46
Author(s):  
Shenela Naqvi ◽  
Prasad Potluri ◽  
Parthasarathi Mandal ◽  
Philip S. Lewis
Keyword(s):  
Mechanical Properties ◽  
Blood Pressure ◽  
Pressure Distribution ◽  
Pressure Measurement ◽  
Indirect Method ◽  
Blood Pressure Measurement ◽  
Simulation Models ◽  
Element Analysis ◽  
Different Types ◽  
Good Agreement

Inflatable cuffs of different types are used for the measurement of blood pressure using the indirect method. It is crucial to find pressure distribution and transmission underneath different types of blood pressure measurement cuffs for estimating accurate values of blood pressure. In this study, three simulation models are developed mimicking blood pressure measurement through three cuffs constructed using fabrics that have dissimilar geometric and mechanical properties. Finite element analysis (FEA) is carried out to predict pressure distribution and transmission underneath these cuffs. For validation of these models, an arm simulator was developed. The models provide good agreement with the experimental results. The pressure distribution at the interface of the selected cuffs and arm is not identical.

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