Papers by Keyword: Computer Simulation

Abstract: The prospects of 3D printed plastic tooling in the processing of metal forming are shown. The study of the process of thin sheet, forming of aluminum 3003 ANSI, established that in this process the destruction and plastic deformation of the plastic tool does not occur. Lubrication of plastic matrices and punches were not required, as they have anti-friction properties. Computer simulation of this process in the software system "Simufact.forming" accurately reflects the force parameters, stress-state of plastic tool and the actual course of the process of forming the blank, including the spring-back of the part after forming. Technology of sheet forming with plastic tool can be recommended for single and small batch production.

Abstract: The paper is devoted to the computer simulation of polymer composite beams dynamic behavior. The use opportunity of one-dimensional beam models for the design of composite elements instead of three-dimensional ones is discussed. The tree-dimensional modeling is implemented using the finite-element software SIMULIA Abaqus considering the orthotropic properties of the composite material. For the one-dimensional modeling two hypothesis of the internal friction – local and nonlocal – are applied and compared. The Kelvin-Voigt hypothesis is used as a local damping model. The nonlocal model is based on the nonlocal mechanics principals and obtained using the Galerkin method. The example glass fiber reinforced plastic beam with the fixed ends is considered under an instantly applied load. The parameters of the nonlocal damping model are defined using the least squares method. The flexibility of the nonlocal damping model is shown and the use opportunity of one-dimensional beam models for the design of composite elements is justified.

Abstract: The paper considers the technology of manufacturing flange parts using local methods of metal forming. Various technologies of manufacturing of ring blanks for the subsequent rotary forging of flanges are offered and investigated. On the basis of computer simulation, the main dimensions of the workpiece have been chosen, providing the best forming parts and the parameters of the technology mode. The results of experimental studies have shown that this technology is possible to manufacture flanges according to EN 1092 using the process of axial rotary forging with cylindrical rolls. The use of local methods of deformation of metals allows expanding the possibilities of technological processes at lower power equipment.

Abstract: Basing on the developed methodology for data transfer between the ProCAST and Deform-3D software products, which allows exporting geometry, temperature, residual stresses and microstructure of the casting, it is simulated semi-continuous casting of ingots from aluminum alloy 5182 into a direct chill mold and their following hot rolling in a reversing rolling stand to with aim to study microstructure the evolution.

Abstract: The copper nanoparticles were obtained by evaporating the metal by the relativistic electron beam. The average size of synthesized particles was about 120 nm. They were characterized by X-ray diffraction, transmission electron microscopy. The results of the X-ray diffraction showed high content of the pure copper for closed setup with an inert gas. Transmission electron microscopy cleared some particles to have an icosahedral structure. These nanoparticles were obtained when the target was exposed by the beam with the highest current strength used in the experiment and the highest cooling of the copper vapor. The process of copper nanoparticle formation by the molecular dynamic method using EAM – potentials (potentials in the Embedded Atom Method form) was studied.

Abstract: The paper presents the methods for forecasting the structure and geometrical parameters of casts by using the ProCAST system of engineering analysis. Based on experimental studies and computer simulation, a regularity between the supercooling rate of aluminium alloy on the one hand and the nucleation rates and crystal growth rates on the other has been established. There have also been established dependencies describing the change in the plasticity modulus, the coefficient of thermal linear expansion, Poisson's coefficient within the temperature range of 20 to 1000°C for cores made from α-set mixture. The computer simulation based on the experimental data of the processing of silumin casts made it possible to forecast the alloy structure with the probability level of 95%, and to calculate the accuracy of hindered contraction of the alloy with accuracy equal to ± 1.5%.

Abstract: The operational properties of thermal insulation materials directly depend on their structure. The processes of pore formation occur inside the material after high-temperature treatment, which makes their studying more expensive and complicated. On the basis of experimental data, a computer simulation program for the process of pore formation has been developed, which makes it possible to simulate the processes of changing the structure of foam glass during heat treatment without repeated laboratory experiments.

Abstract: The hot cracking (solidification cracking) susceptibility in the weld metals of duplex stainless steels were quantitatively evaluated by Transverse-Varestraint test with gas tungsten arc welding (GTAW) and laser beam welding (LBW). Three kinds of duplex stainless steels (lean, standard and super duplex stainless steels) were used for evaluation. The solidification brittle temperature ranges (BTR) of duplex stainless steels were 58K, 60K and 76K for standard, lean and super duplex stainless steels, respectively, and were comparable to those of austenitic stainless steels with FA solidification mode. The BTRs in LBW were 10-15K lower than those in GTAW for any steels. In order to clarify the governing factors of solidification cracking in duplex stainless steels, the solidification segregation behaviours of alloying and impurity elements were numerically analysed during GTAW and LBW. Although the harmful elements to solidification cracking such as P, S and C were segregated in the residual liquid phase in any joints, the solidification segregation of P, S and C in LBW was inhibited compared with GTAW due to the rapid cooling rate in LBW. It followed that the decreased solidification cracking susceptibility of duplex stainless steels in LBW would be mainly attributed to the suppression of solidification segregation of P, S and C.

Abstract: The research purpose is to upgrade the mathematical modelling and computer simulation of quenching of steel. Based on theoretical analyze of physical processes which exist in quenching systems the mathematical model for steel quenching is established and computer software is developed. The mathematical model of steel quenching is focused on physical phenomena such as heat transfer, phase transformations, mechanical properties and generation of stresses and distortions. Physical properties that were included in the model, such as heat conductivity coefficient, heat capacity and surface heat transfer coefficient were obtained by the inversion method based on Jominy test results. The numerical procedure is based on finite volume method. By the developed algorithm, 3D situation problems such as the quenching of complex cylinders, cones, spheres, etc., can be simulated. The established model of steel quenching can be successfully applied in the practical usage of quenching.

Abstract: Quality improvement of the structure of thick sheets and plates, increasing the level of mechanical properties, minimization of energy and labor costs in the process of manufacturing could be achieved by using new methods of die forging and rolling with the implementation of severe alternating deformation. In this work, new methods of rolling of thick steel sheets and die forging for plates made of titanium and aluminum alloys are proposed and studied.