A mathematical model for the dynamic behavior of melts subjected to electromagnetic forces: Part I. model development and comparison of predictions with published experimental results

1998 ◽  
Vol 29 (4) ◽  
pp. 919-928 ◽  
Author(s):  
R. Kageyama ◽  
J. W. Evans
Keyword(s):  
Mathematical Model ◽  
Dynamic Behavior ◽  
Model Development ◽  
Experimental Results ◽  
Electromagnetic Forces

Extended validation of a ground-based three-axis spacecraft simulator model

2020 ◽  
pp. 095441002093896
Author(s):  
H Sh Ousaloo ◽  
Gh Sharifi ◽  
B Akbarinia
Keyword(s):  
Mathematical Model ◽  
Attitude Control ◽  
Aerodynamic Drag ◽  
Center Of Mass ◽  
Model Development ◽  
Optimization Method ◽  
Experimental Results ◽  
Spacecraft Dynamics ◽  
Detailed Model ◽  
Mass Properties

The ground-based spacecraft dynamics simulator plays an important role in the implementation and validation of attitude control scenarios before a mission. The development of a comprehensive mathematical model of the platform is one of the indispensable and challenging steps during the control design process. A precise mathematical model should include mass properties, disturbances forces, mathematical models of actuators and uncertainties. This paper presents an approach for synthesizing a set of trajectories scenarios to estimate the platform inertia tensor, center of mass and aerodynamic drag coefficients. Reaction wheel drag torque is also estimated for having better performance. In order to verify the estimation techniques, a dynamics model of the satellite simulator using MATLAB software was developed, and the problem reduces to a parameter estimation problem to match the experimental results obtained from the simulator using a classical Lenevnberg-Marquardt optimization method. The process of parameter identification and mathematical model development has implemented on a three-axis spherical satellite simulator using air bearing, and several experiments are performed to validate the results. For validation of the simulator model, the model and experimental results must be carefully matched. The experimental results demonstrate that step-by-step implementation of this scenario leads to a detailed model of the platform which can be employed to design and develop control algorithms.

scholarly journals Construction of Evolutionary Mathematical Model of Hierarchical Network Topology

2021 ◽  
Vol 15 ◽  
pp. 1214-1222
Author(s):  
Min Yang
Keyword(s):  
Mathematical Model ◽  
Dynamic Behavior ◽  
Network Topology ◽  
Experimental Results ◽  
Practical Application ◽  
Hierarchical Network ◽  
Effectiveness Index

In order to solve the problem that the traditional hierarchical network topology evolution mathematical model has low accuracy in describing the dynamic behavior of network, the design of hierarchical network topology evolution mathematical model is proposed. This paper analyzes the hierarchical network, establishes the effectiveness index of topology, formulates the strategy of topology reconstruction, realizes the evolution of hierarchical network topology, and completes the design of mathematical model. The experimental results show that the accuracy of the designed mathematical model of hierarchical network topology evolution can reach 94%, and the effect is good in practical application.

Simulation of reciprocating gas compressors with automatic reed valves

SIMULATION ◽  
1967 ◽  
Vol 8 (4) ◽  
pp. 209-214 ◽  
Author(s):  
M.W. Wambsganss ◽  
Donald Coates ◽  
Raymond Cohen
Keyword(s):  
Mathematical Model ◽  
Computer Simulation ◽  
Steady State ◽  
Dynamic Behavior ◽  
High Speed ◽  
Experimental Results ◽  
The Other ◽  
Reciprocating Compressor ◽  
Trial And Error ◽  
State Tests

The simulation of high-speed reciprocating refrigeration compressors was motivated by the needs of design engi neers. In this paper a mathematical model describing the dynamic behavior of a reciprocating compressor is pre sented. The model is semianalytic in that two types of empirical factors are required to relate phenomena not yet analytically predictable. One type is obtained from steady- state tests and the other by trial and error based on com parison with experimental results. Both analog and digital computers were considered as means of simulating the model. Due to nonlinearities in the model, the digital com puter, using Fortran IV, was selected. To evaluate the sim ulation, a one-quarter horsepower 3600-rpm stock com pressor was modified and used as a laboratory vehicle. A typical correlation between the computer simulation and experimental results is given. In general, good correlation was achieved.

Theoretical and Experimental Researches Regarding the Influence of the Suspension Car Stiffness on the Dynamic Behavior of Vehicles

2016 ◽  
Vol 822 ◽  
pp. 36-43
Author(s):  
Dumitru Neagoe ◽  
Dumitru Bolcu ◽  
Loreta Simniceanu ◽  
Mario Trotea
Keyword(s):  
Mathematical Model ◽  
Dynamic System ◽  
Dynamic Behavior ◽  
Experimental Research ◽  
Experimental Results ◽  
Negative Effects ◽  
Experimental Researches ◽  
The Mathematical Model ◽  
Theoretical Results

In this paper the authors present the results of theoretical and experimental research in order to optimize suspension rigidity in case of Daewoo Nubira vehicle. The paper presents the mathematical model obtained by assimilating car with a dynamic system with 5 rigid solids with elastic and viscous linking between them. Theoretical results obtained based on this model and the experimental results are presented, and it is presented a solution to optimize suspension in order to remove the negative effects observed driving on gravel runways or damaged runaways. Theoretical results, compared with the experimental ones, allow us to say that it is possible to optimize suspension by analyzing specific parameters equivalent mathematical model.

Dynamic Simulation of Phenol Biodegradation in a Fluidized Bed Bioreactor Using Genetic Algorithm Trained Neural Network

2008 ◽  
Vol 3 (1) ◽  
Author(s):  
Venu Vinod Ananthula ◽  
Venkat Reddy Goli ◽  
Neelima Murapaka
Keyword(s):  
Genetic Algorithm ◽  
Mathematical Model ◽  
Fluidized Bed ◽  
Dynamic Behavior ◽  
Error Function ◽  
Experimental Results ◽  
Phenol Biodegradation ◽  
Fluidized Bed Bioreactor ◽  
Real Coded Genetic Algorithm ◽  
Biodegradation Process

The aim of this work is to simulate the dynamic behavior of a phenol biodegradation process in a fluidized bed bioreactor (FBR). Pseudomonas putida is used for the biodegradation of phenol. A mathematical model was developed to describe the dynamic behavior of the biodegradation process. The model equations describing the process have been solved, and the rate of biodegradation and the biofilm thickness at different points of time have been determined. The mathematical model has been directly mapped onto the network architecture. The network is used to find an error function. Minimization of error function with respect to the network parameters (weights and biases) has been considered as training of the network. A real-coded genetic algorithm has been used for training the network in an unsupervised manner. The system is tested for two different inlet concentrations of feed. The results obtained are then compared with the experimental results. It is found that there is a good agreement between the experimental results and the results obtained from the model.

Mathematical Model of Flat Surface Machining Inaccuracies due to Elastic Strains of Technological System

2018 ◽  
pp. 1-14 ◽  
Author(s):  
I. I. Kravchenko
Keyword(s):  
Mathematical Model ◽  
Vector Field ◽  
Model Development ◽  
Technological System ◽  
Mutual Arrangement ◽  
Real Surface ◽  
Main Bearing ◽  
Flat Surfaces ◽  
Internal Surfaces ◽  
Elastic Strains

The paper considers the mathematical model development technique to build a vector field of the shape deviations when machining flat surfaces of shell parts on multi-operational machines under conditions of anisotropic rigidity in technological system (TS). The technological system has an anisotropic rigidity, as its elastic strains do not obey the accepted concepts, i.e. the rigidity towards the coordinate axes of the machine is the same, and they occur only towards the external force. The record shows that the diagrams of elastic strains of machine units are substantially different from the circumference. The issues to ensure the specified accuracy require that there should be mathematical models describing kinematic models and physical processes of mechanical machining under conditions of the specific TS. There are such models for external and internal surfaces of rotation [2,3], which are successfully implemented in practice. Flat surfaces (FS) of shell parts (SP) are both assembly and processing datum surfaces. Therefore, on them special stipulations are made regarding deviations of shape and mutual arrangement. The axes of the main bearing holes are coordinated with respect to them. The joints that ensure leak tightness and distributed load on the product part are closed on these surfaces. The paper deals with the analytical construction of the vector field F, which describes with appropriate approximation the real surface obtained as a result of modeling the process of machining flat surfaces (MFS) through face milling under conditions of anisotropic properties.

Friction and Tribological Considerations for Nanometer Range Machining

2001 ◽  
Author(s):  
Som Chattopadhyay
Keyword(s):  
Mathematical Model ◽  
High Precision ◽  
Local Deformation ◽  
Experimental Results ◽  
Precision Machining ◽  
Complex Motion ◽  
Positioning Accuracy ◽  
Nanometer Range ◽  
Motion Characteristic ◽  
Low Speeds

Abstract Positioning accuracy within the range of nanometers is required for high precision machining applications. The implementation of such a range is difficult through the slides because of (a) irregular nature of friction at the slider-guideway interface, and (b) complex motion characteristic at very low speeds. The complexity arises due to the local deformation at the interface prior to breakaway, which is known as microdynamics. In this work prior experimental results exhibiting microdynamics have been appraised, and mathematical model developed to understand this behavior.

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