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Understanding the mechanisms of friction stir welding based on computer simulation using particles

Defence Technology（防务技术） 2018年第6期14卷 643-656页

作者： a.yu.smolin E.V.Shilko S.V.Astafurov E.A.Kolubaev G.M.Eremina S.G.Psakhie Institute of Strength Physics and Materials Science SB RAS Tomsk634055Russia Tomsk State University Tomsk634050Russia Skolkovo Institute of Science and Technology Skolkovo143025Russia

Friction stir welding(FSW) is a novel technique for joining different materials without melting. In FSW the welded components are joined by stirring the plasticized material of the welded edges with a special rotating pin plunged into the material and moving along the joint line. From the scientific point of view,the key role of the FSW processes belongs to formation of the special plasticized conditions and activation of physical mechanisms of mixing the materials in such conditions to produce the strong homogeneous weld. But it is still a lack of complete understanding of what are these conditions and *** paper is devoted to understanding the mechanisms of material mixing in conditions of FSW based on a computer simulation using particles. The movable cellular automaton method(MCA), which is a representative of the particle methods in mechanics of materials, was used to perform all ***, material flow including material stirring in FSW is simulated using computational fluid mechanics or smoothed particle hydrodynamics, which assume that the material is a continuum and does not take into account the material structure. MCA considers a material as an ensemble of bonded particles. Breaking of inter-particle bonds and formation of new bonds enables simulation of crack nucleation and healing, as well as mass mixing and *** paper consists of two main parts. In the first part, the simulations in 2 D statements are performed to study the dynamics of friction stir welding of duralumin plates and influence of different welding regimes on the features of the material stirring and temperature distribution in the forming welded joints. It is shown that the ratio of the rotational speed to the advancing velocity of the tool has a dramatic effect on the joint quality. A suitable choice of these parameters combined with additional ultrasonic impact could considerably reduce the number of pores and microcracks in the weld without significa

关键词： Friction stir welding Plastic flow Deformation mechanisms Simulation Particle method

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Modeling mechanical behaviors of composites with various ratios of matrixeinclusion properties using movable cellular automaton method

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Defence Technology（防务技术） 2015年第1期11卷 18-34页

作者： a.yu.smolin E.V.SHILKO S.V.ASTAFUROV I.S.KONOVALENKO S.P.BUYAKOVA S.G.PSAKHIE Institute of Strength Physics and Materials Science SB RAS Tomsk State University Institute of High Technology Physics Tomsk Polytechnic University Skolkovo Institute of Science and Technology

Two classes of composite materials are considered: classical metaleceramic composites with reinforcing hard inclusions as well as hard ceramics matrix with soft gel inclusions. Movable cellular automaton method is used for modeling the mechanical behaviors of such different heterogeneous materials. The method is based on particle approach and may be considered as a kind of discrete element method. The main feature of the method is the use of many-body forces of inter-element interaction within the formalism of simply deformable element approximation. It was shown that the strength of reinforcing particles and the width of particle-binder interphase boundaries had determining influence on the service characteristics of metaleceramic composite. In particular, the increasing of strength of carbide inclusions may lead to significant increase in the strength and ultimate strain of composite material. On the example of porous zirconia ceramics it was shown that the change in the mechanical properties of pore surface leads to the corresponding change in effective elastic modulus and strength limit of the ceramic sample. The less is the pore size, the more is this effect. The increase in the elastic properties of pore surface of ceramics may reduce its fracture energy.

关键词： Composites Metal ceramics Zirconia ceramics Gel Modeling Movable cellular automata Many-body interaction

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About the Features of Transient to Steady State Deformation of Solids

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Journal of Materials Science & Technology 1997年第1期13卷 69-72页

作者： S. G.Psakhie A. yu.smolin E. V.Shilko S.yu.Korostelev, A.I.Dmitriev and S. V.Alekseev (Institute of Strength Physics and Materials Science of the Russian Academy of Sciences,Siberian Branch 634055, Tomsk, Russia) Institute of Strength Physics and Materials Science Russian Academy of Sciences Siberian Branch 634055 Tomsk Russian Federation

The features of transient to steady state deformation of solids are theoretically *** of various types of loading was carried out by the Movable Cellular Automata method.A stress state of material at the stage of transient to a steady state is shown to be essentially non-uniform, that may in its turn result in stable structures in velocity field of particles of the material. It may also influence development of deformation at the further stages.

关键词： About the Features of Transient to Steady State Deformation of Solids

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