Experimental Validation of a Dynamic Model for Flexible Link Mechanisms

2001 ◽  
Author(s):  
R. Caracciolo ◽  
A. Gasparetto ◽  
A. Trevisani
Keyword(s):  
Mathematical Model ◽  
Experimental Validation ◽  
Numerical Results ◽  
Test Case ◽  
Planar Mechanisms ◽  
Transient Period ◽  
Element Approach ◽  
Multi Body ◽  
The Mathematical Model ◽  
Good Agreement

Abstract This paper presents an experimental validation of a finite element approach for the dynamic analysis of flexible multi-body planar mechanisms. The mathematical model employed accounts for mechanism geometric and inertial non-linearities and considers coupling effects among rigid-body and elastic motion. A flexible five-bar linkage actuated by two electric motors is employed as a test case. Experimentally determined link absolute deformations are compared with the numerical results obtained simulating the system dynamic behavior through the mathematical model. The experimental and numerical results are in good agreement especially after the very first transient period.

On the Modeling of Flexible-Link Planar Mechanisms: Experimental Validation of an Accurate Dynamic Model

2004 ◽  
Vol 126 (2) ◽  
pp. 365-375 ◽  
Author(s):  
Alessandro Gasparetto
Keyword(s):  
Mathematical Model ◽  
Dynamic Model ◽  
Dynamic Behavior ◽  
Experimental Validation ◽  
Test Case ◽  
Planar Mechanisms ◽  
Flexible Links ◽  
Multi Body ◽  
The Mathematical Model ◽  
Flexible Mechanisms

The experimental validation of an accurate dynamic model of flexible multi-body planar mechanisms is presented in this paper. The proposed mathematical model, which is valid for whatever planar mechanism with any number of flexible links, accounts for the geometric and inertial nonlinearities of the mechanism, and considers coupling effects among rigid-body and elastic motion as well. In order to experimentally validate the dynamic model, a flexible five-bar planar linkage actuated by two electric motors is employed as a test case. The experimentally measured deformations and accelerations of the flexible links are compared with the numerical results obtained by simulating the system dynamic behavior through the mathematical model. It turns out that the experimental results are in good agreement with the numerical ones, thus proving that the dynamical model proposed is very effective in the difficult task of accurately representing the dynamic behavior of flexible mechanisms.

Lubrication Analysis of a Rolling Piston Rotary Compressor: Part 2: Experimental Validation and Results

1994 ◽  
Vol 208 (2) ◽  
pp. 95-104
Author(s):  
S K Padhy
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Experimental Validation ◽  
Sensitivity Study ◽  
Rotary Compressor ◽  
Oil Flow ◽  
Different Dimensions ◽  
Rolling Piston ◽  
The Mathematical Model ◽  
Good Agreement

In this paper the experiments conducted for the measurement of oil flow in the rotary compressor are described. The experimental data are compared against the theoretical prediction from the mathematical model developed (1) and a good agreement is found. In addition, experimental data from previously published literature are also used to verify the mathematical model. A sensitivity study is carried out to predict the behaviour of the rotary compressor for the oil flow at different conditions and with different dimensions.

A Study on Exhaust Muffler Using Counter-Phase Counteract

2014 ◽  
Vol 986-987 ◽  
pp. 810-813
Author(s):  
Ying Li Shao
Keyword(s):  
Mathematical Model ◽  
Experimental Validation ◽  
Noise Source ◽  
Low Frequency ◽  
Frequency Noise ◽  
Expansion Chamber ◽  
Band Noise ◽  
Exhaust Noise ◽  
Perforated Pipe ◽  
The Mathematical Model

The exhaust noise, which falls into low-frequency noise, is the dominant noise source of a diesel engines and tractors. The traditional exhaust silencers, which are normally constructed by combination of expansion chamber, and perforated pipe or perforated board, are with high exhaust resistance, but poor noise reduction especially for the low-frequency band noise. For this reason, a new theory of exhaust muffler of diesel engine based on counter-phase counteracts has been proposed. The mathematical model and the corresponding experimental validation for the new exhaust muffler based on this theory were performed.

scholarly journals Computer Simulation of the King's Cross Fire: Effect of Radiative Heat Transfer on Fire Spread

1991 ◽  
Vol 205 (3) ◽  
pp. 201-208 ◽  
Author(s):  
W M G Malalasekera ◽  
F Lockwood
Keyword(s):  
Mathematical Model ◽  
Radiative Heat ◽  
Health And Safety ◽  
Fire Spread ◽  
Future Research ◽  
Full Description ◽  
Department Of Health ◽  
Underground Fire ◽  
The Mathematical Model ◽  
Good Agreement

A mathematical model has been applied to simulate model experiments of the 1987 King's Cross underground fire by the Department of Health and Safety Executive. The predicted growth of the fire is compared with the experimental data and in particular the predicted and measured times to ‘flashover’ are compared. The comparisons show exceptional agreement which, in part, may be fortuitous due to the need to facilitate the prediction of the early stages of the growth with the aid of an experimentally estimated fire strength. The good agreement nonetheless is also due to the full description of the radiation transfer which is a feature of the mathematical model. It is concluded that the flashover phenomenon that occurred at King's Cross was thermal radiation driven and that future research should be devoted to modelling the details of fire spread across a combustible surface.

The Onset of Tear Propagation at Slits in Stressed Uncoated Plain Weave Fabrics

1999 ◽  
Vol 66 (4) ◽  
pp. 926-933 ◽  
Author(s):  
T. A. Godfrey ◽  
J. N. Rossettos
Keyword(s):  
Mathematical Model ◽  
Micromechanical Model ◽  
Crucial Aspect ◽  
Damage Site ◽  
Plain Weave ◽  
Actual Configuration ◽  
Tear Propagation ◽  
The Mathematical Model ◽  
Frictional Slip ◽  
Good Agreement

A simple micromechanical model is developed to predict the onset of tear propagation at slit-like damage sites (i.e., a series of consecutive aligned yarn breaks) in biaxially stressed plain weave fabrics under increasing loading. A crucial aspect of the model is the treatment of the frictional slip of yarns near the damage site. Although the actual configuration of slipping regions is complex, the onset of tear propagation in large slits (i.e., more than, say, 35 breaks) is dominated by slip occurring on the first few intact yarns adjacent to the breaks. The assumptions in the mathematical model were motivated by both experimental observations and calculations for key configurations. Analytical results obtained for this simple model exhibit good agreement with experimental results, which are presented for a variety of fabrics with initial slits of 35 and 45 breaks.

An enhanced composting process with bioaugmentation: Mathematical modelling and process optimization

2021 ◽  
pp. 0734242X2110337
Author(s):  
Tea Sokač ◽  
Anita Šalić ◽  
Dajana Kučić Grgić ◽  
Monika Šabić Runjavec ◽  
Marijana Vidaković ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Model Simulation ◽  
Process Conditions ◽  
Air Flow Rate ◽  
Optimal Process ◽  
Composting Process ◽  
Different Types ◽  
Adiabatic Reactor ◽  
The Mathematical Model ◽  
Good Agreement

In this paper, two different types of biowaste composting processes were carried out – composting without and with bioaugmentation. All experiments were performed in an adiabatic reactor for 14 days. Composting enhanced with bioaugmentation was the better choice because the thermophilic phase was achieved earlier, making the composting time shorter. Additionally, a higher conversion of substrate (amount of substrate consumed) was also noticed in the process enhanced by bioaugmentation. A mathematical model was developed and process parameters were estimated in order to optimize the composting process. Based on good agreement between experimental data and the mathematical model simulation results, a three-level-four-factor Box-Behnken experimental design was employed to define the optimal process conditions for further studies. It was found that the air flow rate and the mass fraction of the substrate have the most significant effect on the composting process. An improvement of the composting process was achieved after altering the mentioned variables, resulting in shorter composting time and higher conversion of the substrate.

KINEMATIC WAVE EQUATIONS FOR MOVABLE RIVERBEDS

2021 ◽  
pp. 43-54
Author(s):  
A. N. Krutov ◽  
◽  
S. Ya. Shkol’nikov ◽  
Keyword(s):  
Mathematical Model ◽  
Numerical Method ◽  
Wave Equations ◽  
Simple Wave ◽  
Kinematic Wave ◽  
Calculation Results ◽  
Self Similar ◽  
Similar Solutions ◽  
The Mathematical Model ◽  
Good Agreement

The mathematical model of kinematic wave, that is widely used in hydrological calculations, is generalized to compute processes in deformable channels. Self-similar solutions to the kinematic wave equations, namely, the discontinuous wave of increase and the “simple” wave of decrease are generalized. A numerical method is proposed for solving the kinematic wave equations for deformable channels. The comparison of calculation results with self-similar solutions revealed a good agreement.

A Differential Equation of the First Law of Thermodynamics for Modeling the Indicator Process of a Diesel Engine

1997 ◽  
Author(s):  
Stanislav N. Danov
Keyword(s):  
Mathematical Model ◽  
Diesel Engine ◽  
High Pressure And Temperature ◽  
First Law Of Thermodynamics ◽  
Ideal Gases ◽  
Working Medium ◽  
Engine Cylinder ◽  
Computing Procedure ◽  
The Mathematical Model ◽  
Good Agreement

Abstract Several improvements to the mathematical model of the indicator process taking place at a diesel engine cylinder are proposed. The thermodynamic behavior of working medium is described by the equation of state, valid for real gases. Mathematical dependencies between thermal parameters (P, T, v) and caloric parameters (u, h, cv, cp) have been obtained. An improved mathematical model, based on the first law of thermodynamics, has been developed, taking into account working medium imperfections. The numerical solution of the simultaneous differential equations is made by a method of Runge-Kutta type. The computing procedure is iterative. Calculations in respect to the caloric parameters (u, h, cv and cp) for various gases under pressure up to 25 MPa and temperature up to 3000°C have been carried out. The results show, that there are significant differences between the values, calculated by equations for ideal gases, and the proposed equations for real gases under high pressure and temperature. Actual applied problems for two-stroke turbocharged engines Sulzer-RLB66 and 8DKRN 74/160 have been solved. The comparison between the experimental data and numerical results show very good agreement. The numerical experiments show that if the pressure is above 8–9 MPa, the working medium imperfections must be taken into consideration.

Experimental and Theoretical Investigation of Performance of a Solar Chimney Model Part II: Model Development and Validation

2021 ◽  
Vol 5 (2) ◽  
Author(s):  
Ibrahim A Abuashe ◽  
Bashir H Arebi ◽  
Essaied M Shuia
Keyword(s):  
Mathematical Model ◽  
Power Output ◽  
Model Development ◽  
Geometrical Parameters ◽  
Balance Equations ◽  
Solar Chimney ◽  
And Performance ◽  
Development And Validation ◽  
The Mathematical Model ◽  
Good Agreement

A mathematical model based on the momentum, continuity and energy balance equations was developed to simulate the behavior of the air flow inside the solar chimney system. The model can estimate the power output and performance of solar chimney systems. The developed mathematical model is validated by the experimental data that were collected from small pilot solar chimney; (experiment was presented in part I). Good agreement was obtained between the experimental results and that from the mathematical model. The model can be used to analyze the solar chimney systems and to determine the effect of geometrical parameters such as chimney height and collector diameter on the power output and the efficiency of the system

scholarly journals Free Interfaces at the Tips of the Cilia in the One-Dimensional Periciliary Layer

Mathematics ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1961
Author(s):  
Kanognudge Wuttanachamsri
Keyword(s):  
Mathematical Model ◽  
Exact Solution ◽  
Free Boundary ◽  
Horizontal Plane ◽  
Numerical Solutions ◽  
Numerical Results ◽  
Brinkman Equation ◽  
Average Height ◽  
Free Interface ◽  
The Mathematical Model

Cilia on the surface of ciliated cells in the respiratory system are organelles that beat forward and backward to generate metachronal waves to propel mucus out of lungs. The layer that contains the cilia, coating the interior epithelial surface of the bronchi and bronchiolesis, is called the periciliary layer (PCL). With fluid nourishment, cilia can move efficiently. The fluid in this region is named the PCL fluid and is considered to be an incompressible, viscous, Newtonian fluid. We propose there to be a free boundary at the tips of cilia underlining a gas phase while the cilia are moving forward. The Brinkman equation on a macroscopic scale, in which bundles of cilia are considered rather than individuals, with the Stefan condition was used in the PCL to determine the velocity of the PCL fluid and the height/shape of the free boundary. Regarding the numerical methods, the boundary immobilization technique was applied to immobilize the moving boundaries using coordinate transformation (working with a fixed domain). A finite element method was employed to discretize the mathematical model and a finite difference approach was applied to the Stefan problem to determine the free interface. In this study, an effective stroke is assumed to start when the cilia make a 140∘ angle to the horizontal plane and the velocitiesof cilia increase until the cilia are perpendicular to the horizontal plane. Then, the velocities of the cilia decrease until the cilia make a 40∘ angle with the horizontal plane. From the numerical results, we can see that although the velocities of the cilia increase and then decrease, the free interface at the tips of the cilia continues increasing for the full forward phase. The numerical results are verified and compared with an exact solution and experimental data from the literature. Regarding the fixed boundary, the numerical results converge to the exact solution. Regarding the free interface, the numerical solutions were compared with the average height of the PCL in non-cystic fibrosis (CF) human tissues and were in excellent agreement. This research also proposes possible values of parameters in the mathematical model in order to determine the free interface. Applications of these fluid flows include animal hair, fibers and filter pads, and rice fields.

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