Computer Simulation of a Test Rig to Model Sloshing in Spin-Stabilized Satellites

1992 ◽  
Vol 114 (4) ◽  
pp. 689-698 ◽  
Author(s):  
D. R. Flugrad ◽  
L. A. Obermaier
Keyword(s):  
Model Simulation ◽  
Test Rig ◽  
Dynamic Motion ◽  
Experimental Project ◽  
Rotating Structure ◽  
Simulation Results ◽  
Parameter Values ◽  
The Mathematical Model ◽  
Two Degree Of Freedom ◽  
Good Agreement

Certain communications satellites carry liquid stores on board for station tending and attitude adjustment. However, sloshing of the liquid can cause an undesirable nutational motion of the spin-stabilized vehicle. In previous work a test rig was designed, built and instrumented to study the interaction between the rotating structure and liquid. To augment that experimental project, a computer model of the test rig has been developed to simulate the dynamic motion of the system for various parameter values. The sloshing liquid was replaced by a two degree-of-freedom pendulum in the mathematical model. Simulation results were compared with those from a general multibody dynamics program and with experimental measurements of the test rig motion to demonstrate the mathematical model’s validity. Good agreement was achieved in both instances.

scholarly journals Population Behavior in the Mathematical Model of the Spread of COVID19 Type SEIRS

2021 ◽  
Vol 6 (2) ◽  
pp. 83-88
Author(s):  
Asmaidi As Med ◽  
Resky Rusnanda
Keyword(s):  
Mathematical Modeling ◽  
Numerical Simulation ◽  
Mathematical Model ◽  
Everyday Life ◽  
Applied Mathematics ◽  
Living Things ◽  
Simulation Results ◽  
Parameter Values ◽  
The Mathematical Model ◽  
Disease Free

Mathematical modeling utilized to simplify real phenomena that occur in everyday life. Mathematical modeling is popular to modeling the case of the spread of disease in an area, the growth of living things, and social behavior in everyday life and so on. This type of research is included in the study of theoretical and applied mathematics. The research steps carried out include 1) constructing a mathematical model type SEIRS, 2) analysis on the SEIRS type mathematical model by using parameter values for conditions 1and , 3) Numerical simulation to see the behavior of the population in the model, and 4) to conclude the results of the numerical simulation of the SEIRS type mathematical model. The simulation results show that the model stabilized in disease free quilibrium for the condition  and stabilized in endemic equilibrium for the condition .

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.

scholarly journals Dynamic analysis of material motion using MATLAB/Simulation environment and test verification

2020 ◽  
Vol 12 (9) ◽  
pp. 168781402095780
Author(s):  
Mei Fang ◽  
Zhihong Yu ◽  
Wenjie Zhang
Keyword(s):  
Dynamic Analysis ◽  
Structural Design ◽  
Simulation Analysis ◽  
Model Simulation ◽  
Maximum Relative Error ◽  
Matlab Simulation ◽  
Simulation Results ◽  
Low Efficiency ◽  
Test Verification ◽  
The Mathematical Model

Throwing device is an important factor that directly affects the performance of chaff cutter. In this work, the dynamic analysis linked with the problem of low efficiency and residue blockage of disc knife chaff cutter is executed. Based on this perspective, the mathematical model, simulation, and testing of the material movement have been carried out. Simulations are performed in MATLAB/Simulink environment. An anemometer records the airflow velocity, which provides data for simulation analysis. The simulation results showed that during the movement along the blade, the material first performs deceleration and then accelerates; in other stages, only deceleration. And finally calculated the throwing distance. To support the presented simulations, an experimental study is conducted. The experimental results are compared with simulation results, the maximum relative error between the simulated value and the experimental value is 9.42%, which verified the correctness of the model. This research provides a theoretical basis for the structural design, parameter optimization, and matching of the chaff cutter.

scholarly journals Finite Element Modelling and Simulating Effects of Hairiness Performance on Hairiness Entanglement During Fabric Pilling

2021 ◽  
Author(s):  
Qi Xiao ◽  
Rui Wang ◽  
Hongyu Sun ◽  
Jingru Wang
Keyword(s):  
Finite Element ◽  
Finite Element Simulation ◽  
Strain Energy ◽  
Dissipation Energy ◽  
Motion Equations ◽  
Dynamic Motion ◽  
Element Simulation ◽  
Frictional Dissipation ◽  
Simulation Results ◽  
Good Agreement

Abstract For analyzing behaviors of hairiness entanglement during fabric pilling, nonlinear dynamic motion equations are deduced based on the elastic thin rod element, combined with the moving characteristics of hairiness, which follow the principles of mechanical equilibrium and energy conservation. The finite element simulation model of the effects of hairiness performance on behaviors of hairiness entanglement was established by ABAQUS. The analysis solution values of nonlinear dynamics were compared with the finite element simulation results. The results showed that hairiness elastic modulus, hairiness friction coefficient and hairiness diameter have significant effects on frictional dissipation energy, strain energy and kinetic energy produced by hairiness entanglement during pilling. Compared the finite element simulation results with analysis solution values, they are in good agreement. The fitness is greater than 0.96, which verifies the validity of finite element method.

A Study of Simulation Model of Doubly-Fed Motor Based on Matlab/Simulink

2013 ◽  
Vol 816-817 ◽  
pp. 625-628
Author(s):  
Xian Biao Chen
Keyword(s):  
Simulation Model ◽  
Model Simulation ◽  
Regulation System ◽  
Motor Simulation ◽  
Unity Power Factor ◽  
Two Phase ◽  
Speed Regulation ◽  
Simulation Results ◽  
Doubly Fed ◽  
The Mathematical Model

This paper introduces the characteristics of doubly-fed motor. The mathematical model in the two-phase synchronous rotating coordinate system d-q of doubly-fed motor is given, and a simulation model is constructed by Matlab S-function based on the model. Simulation of doubly-fed motor on stator unity power factor vector control is carried out through the model and simulating waveforms are given. The simulation results illustrate that the doubly-fed motor simulation model by S-function has the characteristics of simple, fast and high precision. It provides a convenient pathway for the research of doubly-fed speed regulation system.

scholarly journals Temperature dependent analytical model for submicron GaAs-MESFET

2021 ◽  
Vol 10 (3) ◽  
pp. 1271-1282
Author(s):  
Mohamed Djouder ◽  
Arezki Benfdila ◽  
Ahcene Lakhlef
Keyword(s):  
Analytical Model ◽  
Temperature Dependent ◽  
Gaas Mesfet ◽  
Voltage Variation ◽  
Proposed Model ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Simulation Results ◽  
Parameter Values ◽  
Good Agreement

MESFET are used in circuitsof gigahertz frequencies as they are based on gallium arsenide (GaAs) having electron mobility six times higher than that of silicon. An analytical model simulating different device current-voltage characteristics, i.e., output conductance and output transconductance of a 0.3μm gate MESFET with temperature dependence is proposed. The model is validated by comparing the results of the proposed model and those of the numerical simulation. The parameter values are computed using an intrinsic MESFET of two-dimensional geometry. In this work, the distribution of different output loads for varied applied voltages is considered. Simulation results obtainedunder temperature variation effectsfor load distribution and applied driven voltage variation are considered. The RMS and average errors between the different models and GaAs MESFET simulations are calculated to evidence the proposed model accuracy. This was demonstrated by a good agreement between the proposed model and the simulation results, which are found in good agreement. The simulation results obtained under temperature variations were discussed and found to complement those obtained in the literature. This clarifies the relevance of the suggested model analytical.

Asymptotic Analysis of the Torsional Vibrations in Reciprocating Machinery

1996 ◽  
Vol 118 (3) ◽  
pp. 485-490 ◽  
Author(s):  
H. Ashrafiuon ◽  
A. M. Whitman
Keyword(s):  
Numerical Modeling ◽  
Steady State ◽  
Asymptotic Analysis ◽  
Degree Of Freedom ◽  
Torsional Vibrations ◽  
Transient Vibration ◽  
Asymptotic Expressions ◽  
Parameter Values ◽  
Two Degree Of Freedom ◽  
Good Agreement

A class of two degree of freedom reciprocating machines is analyzed and simple asymptotic expressions for both the steady state and transient vibration levels are obtained. The results are compared with those of a standard numerical modeling package, and are found to be in good agreement for parameter values typical of real machines. This happens because real machines are designed so that the vibration levels are small, thereby satisfying the conditions for the validity of the approximation.

Asymptotic Analysis of the Torsional Vibrations in Reciprocating Machinery

1995 ◽  
Author(s):  
Hashem Ashrafiuon ◽  
Alan M. Whitman
Keyword(s):  
Numerical Modeling ◽  
Steady State ◽  
Asymptotic Analysis ◽  
Degree Of Freedom ◽  
Torsional Vibrations ◽  
Transient Vibration ◽  
Asymptotic Expressions ◽  
Parameter Values ◽  
Two Degree Of Freedom ◽  
Good Agreement

Abstract A class of two degree of freedom reciprocating machines is analysed and simple asymptotic expressions for both the steady state and transient vibration levels are obtained. The results are compared with those of a standard numerical modeling package, and are found to be in good agreement for parameter values typical of real machines. This happens because real machines are designed so that the vibration levels are small, thereby satisfying the conditions for the validity of the approximation.

scholarly journals Experimental Verification of Model Simulation Results of Heating Cycles within the Electric Muffle Furnaces

2020 ◽  
Vol 5 (2) ◽  
pp. 36-46
Author(s):  
Jiří Lucák
Keyword(s):  
Mathematical Model ◽  
Silicon Carbide ◽  
Thermal Insulation ◽  
Experimental Verification ◽  
Model Simulation ◽  
Heating Furnace ◽  
Font Size ◽  
Muffle Furnace ◽  
Simulation Results ◽  
The Mathematical Model

<p><span style="font-family: Times New Roman; font-size: small;">The paper [1] described a mathematical model of the electric muffle furnace. A specific solution of real models has been already solved and presented within this paper. The first one is the muffle heating furnace equipped with a fireproof clay muffle (MODEL I) and thermal insulation of expanded fireproof clay. As the second variant the furnace equipped with a silicon carbide muffle (MODEL II) and with a thermal insulation of fibre ceramic boards of Sibral type is presented. Further the paper presents the results of simulations of the same heating cycles performed using the mathematical model presented in the paper [1] and comparing these results with the progression of the values measured in real furnaces.</span></p><p><span style="font-family: Times New Roman; font-size: small;">Experiment and simulation assessment will be carried out as the final step hereof. Equipment parameters are sources from technical documentations of the manufacturers.</span></p>

The Model Simulation Analysis of Electro-Rheological Fluid Engine Mounting System

2013 ◽  
Vol 694-697 ◽  
pp. 338-343 ◽  
Author(s):  
Bo Jiang ◽  
Wen Ku Shi
Keyword(s):  
Mathematical Model ◽  
Electric Field ◽  
Vibration Isolation ◽  
Simulation Analysis ◽  
Model Simulation ◽  
Simulation Results ◽  
Set Up ◽  
The One ◽  
The Mathematical Model ◽  
Better Than

The mathematical model of the electro-rheological fluid engine mounting system is set up, Combining the electro-rheological fluid effect with hydraulic mount technology and considering the flexibility of the car frame. The simulation model of electro-rheological fluid engine mounting system is build up by the Simulink module of Matlab software to simulate the representative situations of the system, and the displacement and acceleration characteristic curves of the powerplant and the car frame is received. The simulation results indicate that the vibration isolation capability of the system with electric field is better than the one without electric field.

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