scholarly journals Definition of the Mathematical Model Coefficients on the Weld Size of Butt Joint Without Edge Preparation

Author(s):  
Vladimir P Sidorov ◽  
Anna V Melzitdinova
Author(s):  
Ljubinko B Kevac ◽  
Mirjana M Filipovic ◽  
Ana M Djuric

Characteristic construction of cable-suspended parallel robot of artificial muscle, which presents an artificial forearm, is analyzed and synthesized. Novel results were achieved and presented. Results presented in this paper were initially driven to recognize and mathematically define undefined geometric relations of the artificial forearm since it was found that they strongly affect the dynamic response of this system. It gets more complicated when one has more complex system, which uses more artificial muscle subsystems, since these subsystems couple and system becomes more unstable. Unmodeled or insufficiently modeled dynamics can strongly affect the system’s instability. Because of that, the construction of this system and its new mathematical model are defined and presented in this paper. Generally, it can be said that the analysis of geometry of selected mechanism is the first step and very important step to establish the structural stability of these systems. This system is driven with two actuators, which need to work in a coordinated fashion. The aim of this paper is to show the importance of the geometry of this solution, which then strongly affects the system’s kinematics and dynamics. To determine the complexity of this system, it was presumed that system has rigid cables. Idea is to show the importance of good defined geometry of the system, which gives good basis for the definition of mathematical model of the system. Novel program package AMCO, artificial muscle contribution, was defined for the validation of the mathematical model of the system and for choice of its parameters. Sensitivity of the system to certain parameters is very high and hence analysis of this system needs to be done with a lot of caution. Some parameters are very influential on the possible implementation of the given task of the system. Only after choosing the parameters and checking the system through certain simulation results, control structure can be defined. In this paper, proportional–derivative controller was chosen.


2019 ◽  
Vol 27 (4) ◽  
pp. 86-100
Author(s):  
Oleg Viktorovich Lutz ◽  
Galina Alexandrovna Borshchova ◽  
Evgeny Dmitrievich Yarmolchuk ◽  
Alexander Alekseevich Manoilenko

Currently increased interest in satellite images of the Earth's surface with high resolution terrain  (1 to 10 m). To obtain such images, you must use a long focus optical system (OS) having a limited field of view that does not allow the images of the large width. To increase the effectiveness of shooting in modern space systems (SS) Earth observation provides the opportunity after shooting a segment of the Earth's surface to redirect the OS to another area and spend it shooting. With sufficient speed shift OS it is possible to survey two or more adjacent parcels, which is almost equivalent to the corresponding increase in the width of the field of view of the removing apparatus. In this connection there is the task of restoring the OS, which is solved by the use of appropriate hardware and software control the angular movement of the removing apparatus. When creating the SS there is also the need to solve the following tasks: calculation of the program angular motion in a given length of the removable sections and a predetermined number of adjacent strips to be shot, with the purpose of definition of system requirements, spacecraft (SC) control and calculation under given characteristics of the system orientation of the SC possible number of the maximum length and remove adjacent portions of the surface of the Earth. To solve these tasks the mathematical model software of angular motion of the SC. Given the necessary initial data, mathematical model and method of calculation of kinematic parameters of a software angular motion of a SC in the mode of area highway shooting adjacent sections of the Earth's surface located at a predetermined distance from a trace route SC; examples and results of numerical calculations of the programmes angular motion by moving the instrument in remote sensing.


2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Shanhui Liu ◽  
Xuesong Mei ◽  
Jian Li ◽  
Li'e Ma

In the latest type of gravure printing machines referred to as the shaft-less drive system, each gravure printing roller is driven by an individual servo motor, and all motors are electrically synchronized. The register error is regulated by a speed difference between the adjacent printing rollers. In order to improve the control accuracy of register system, an accurate mathematical model of the register system should be investigated for the latest machines. Therefore, the mathematical model of the machine directional register (MDR) system is studied for the multicolor gravure printing machines in this paper. According to the definition of the MDR error, the model is derived, and then it is validated by the numerical simulation and experiments carried out in the experimental setup of the four-color gravure printing machines. The results show that the established MDR system model is accurate and reliable.


2015 ◽  
Vol 1095 ◽  
pp. 476-482 ◽  
Author(s):  
A.N. Dmitriev ◽  
Maxim O. Zolotykh ◽  
Yury A. Chesnokov ◽  
Oleg Yu. Ivanov ◽  
Galina Yu. Vitkina

In a laying of a hearth it is usually used to ten different types of the flameproof materials. The characteristics of materials declared by the manufacturer can differ from the actual. For creation of the mathematical model [1, 2] temperatures distributions in a laying of the concrete furnace it is necessary to know thermal conductivity of materials of the specific parties used at construction of the furnace. Definition of the thermal conductivity coefficient allows adapt mathematical model for specific conditions of use. The technique of determination of thermal properties of refractory materials on the temperatures acceleration curve at blowing-in of the blast furnace is described.


Author(s):  
Emma Frosina ◽  
Adolfo Senatore ◽  
Dario Buono ◽  
Michele Pavanetto ◽  
Micaela Olivetti ◽  
...  

The paper introduces a methodology aimed to optimize the performance of hydraulic components; in particular the design of a new two way flow control valve studying the valve internal fluid-dynamic behavior will be introduced. The methodology is based on the definition of a CFD tridimensional fluid-dynamic model. In fact, the model can help engineers to develop the best geometry, to optimize the valve performance, reducing the prototyping requirement and finally the time-to-market and, consequently, the development costs. At first, the original spool internal geometry has been evaluated and studied to tune the mathematical model and to validate it comparing its results with the data obtained through an experimental campaign. Then, the same approach has been applied to investigate several different internal spool geometries to define the best one in all operating conditions. A limited number of solutions have been prototyped and tested to verify the mathematical model predictions, in order to find the best configuration whose performances are consistent with the assigned objective for the component.


1964 ◽  
Vol 18 (4) ◽  
pp. 481-498 ◽  
Author(s):  
J. T. Stuart

In the theory of thermal convective instability between two horizontal planes there are many solutions that are periodic in the horizontal co-ordinates, while in experiment convection is observed to take place in cellular patterns. It is often assumed, or decided after insufficient argument, that the periodic solutions of the mathematical model ‘explain’ or correspond to these patterns, but a completely satisfactory discussion of this correspondence has not been given. Indeed, with certain mathematical solutions ambiguities arise as to what cell centres and cellular boundaries are. A detailed discussion has recently become especially necessary because attempts are being made to predict which particular cellular pattern will occur in given experimental conditions.In this paper the topic is studied afresh and the question is asked: what features, in the mathematical model, correspond to what an experimentalist observes in cellular convective motion? In answer a definition of a cell is formulated which relates certain surfaces in the flow field of the mathematical model to steady vertical cellular boundaries that are observed in experiment, and which shows where the cell centres lie. In particular the classical hexagonal cellular pattern, of the mathematical model, is shown to be the prototype pattern of what is experimentally observed. On the other hand the square and so called ‘rectangular’ cases of linearized theory are shown not to correspond truly to square and rectangular cells at all. The new formulation is especially relevant to theoretical work on the prediction of cell shape and direction of flow in cells, since precise knowledge of the shapes of the cellular boundaries and locations of cell centres is essential if predictions are to be compared with observation.


Author(s):  
Mehdi Mohammadpour ◽  
Iraj Mirzaee ◽  
Shahram Khalilarya

This paper firstly presents a mathematical model in order to calculate the load distribution, single contact stiffness and meshing stiffness as well as transmission error. in this way, there is no need to use finite element like methods and also the calculation time is dramatically reduced. Presented method is based on definition of a statically undetermined problem that is formulated using energy method. Some assumptions considered to convert this problem to a statically determined problem and get the mathematical models. Then a numerical method is employed in order to solve the mathematical model using a double iteration flowchart to close the problem. This model is flexible to adapt for any modification in spur gear profile geometry. Finally, this model is verified using previous works that have been utilized finite element and experimental model.


2014 ◽  
Vol 494-495 ◽  
pp. 354-357 ◽  
Author(s):  
Gen Bao Zhang ◽  
Lian Zhang ◽  
Yan Ran

Since the element action (e-action) is the smallest motion unit in realizing systems function, its reliability plays an important role in system operating ability. In this paper, a new method of CNC machines reliability analysis based on e-action is proposed. Firstly, the definition of e-action reliability is studied and the mathematical model is built. Then the methodology of FMECA based on e-action is introduced. Finally the grinding carriage feed movement is taken as an example to illustrate the methodology.


2021 ◽  
Vol 6 (166) ◽  
pp. 175-183
Author(s):  
I. Soloviev

It is shown that the problem of improving the effectiveness of prevention of emergencies related to the underwater location of explosive objects is relevant. An important and unresolved part of the problem is the lack of a mathematical model of the emergency response process associated with the underwater location of an explosive device in general. Based on this, the object of the study was the elimination of an emergency situation related to the underwater location of explosive objects, and the subject of the study – the process of operational activities of personnel of the underwater demining department of a group of special diving rescue team. The aim of the work is to develop a mathematical model of the emergency response process related to the underwater location of an explosive object as a process of functioning of the system "emergency – special means of underwater demining – diver-sapper", which should be the basis for substantiation of operational and technical recommendations. increasing the efficiency of underwater demining by diver sappers without reducing their level of safety. It is shown that the mathematical model of underwater demining by a diver-sapper is a system of three analytical dependences. The first is a functional that describes the process of underwater demining in the form of a three-factor polynomial model. The second allows us to present this functionality as a set of one-factor models. The third provides the definition of weights in solving a multifactor problem. It is noted that such a model allows to proceed to the substantiation of operational and technical recommendations to the management of the group of special diving works. The advantage of the new scientific result is the ability to obtain both quantitative estimates of the impact of the direct components of the system "diver-sapper – special means of underwater demining – underwater location of an explosive object" and their relationship. The disadvantage is the large number of experimental results that must be obtained to implement the selected plan.


2020 ◽  
Vol 11 (3) ◽  
pp. 129-133
Author(s):  
S. I. Bondariev ◽  

Transport processes research are closely related to the economic and operational performance of road transport. During planning road transportation, the most important factor is the transport services cost. Known fact that most of the transportation costs are car fuel. The share of car fuel in the transport tariff cost can be 25-50% (depending on the working conditions of vehicles). Therefore, research that is associated with improving the vehicles efficiency by reducing variable costs is appropriate and relevant. The article presents the results of research on the planning of transport processes in the road transport performance in international road transport for the return flight and calculating methods the demand for the amount of fuel purchased in different countries with different prices. The author presents the results of theoretical and experimental research the adequacy of the mathematical model (methodology). The specified mathematical model consists in substantiation of a technique of calculation of quantity of car fuel, definition of the variable factors influencing volumes of fuel expenses, calculation of correction factors (total) received on the basis of technical and operational indicators of vehicles and the influencing factors connected with features of road transport work. . The second part of the research contains the results of the development of an algorithm development to calculate the total cost of automotive fuel, which was purchased at different prices in several countries. Thus, the main purpose of research is the task of substantiating the algorithm (mathematical model – methodology) for determining fuel costs by the criterion of the highest use of fuel in countries at the lowest prices.


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