Advanced Materials Research Vol. 1040

Abstract: The article is devoted to the investigation of alumina-zirconia ceramics properties depending on its production technology. Analysis of the technological factors that allow acquiring fine-grained structure as well as high physical and mechanical properties of alumina-zirconia ceramics is presented in the paper. It is shown that when using magnetic pulse compaction due to the pulse impact and adiabaticity of the process the most compact structure is formed. It is possible to obtain pressings with the density of up to 68% of the theoretical value. The obtained compact structure secures high physical, mechanical, and operating characteristics of the finished product.

Abstract: The processes taking place in a drop of a molten electrode metal and in a metal of a weld pool play the dominant role in formation of joint welds properties. In consumable electrode welding with jet gas shielding under certain conditions a drop of an electrode metal is influenced by the main forces as well as by the force of a shielding gas jet impact which depends upon the method and composition of a gas shielding in a welding area. The results of research have stated that the force of a shielding gas jet impact on a drop of an electrode metal in double-jet gas shielding is twelvefold as in one-jet one; it is directed along the electrode to a workpiece and stimulates stability of the electrode metal drops transfer into a weld pool.

Abstract: Exothermic reaction in thermite charge of casting pattern was investigated by estimated and experimental techniques. Thermophysical properties of steel mouldings production in graphitic shell molds were determined.

Abstract: The article focuses on modelling the behaviour of a liquid-type automatic balancing device. To perform mathematical research the rotor model is used that contains a ring functioning as a vessel coupled to the rigid shaft being rotatable on bearings. Data on the influence of various factors on balancing accuracy are presented. The obtained modeling results indicate that the vibration amplitude at supercritical frequencies will decrease proportionally to the increase in the parameters of a liquid autobalancer. The performed calculation also reveals that the more the parameters of a liquid autobalancing device, the higher the efficiency of balancing. Provided the condition of the liquid sufficiency in the ring is satisfied, the independence of the rotor vibration amplitude from the mass of the liquid in the vessel is achieved. Critical rotor speed does not depend on the volume of the liquid in the ring if the condition of its sufficiency is met.

Abstract: The process of shock disturbances in incompressible nonlinear elastic medium is considered. For the case of one-dimensional deformation the two types of plane shock waves are shown, which carry shift deformations in the medium. The properties of these waves are described, their propagation velocities are calculated. The solution of the boundary problem of the interaction of two plane waves with different shear polarization is presented to demonstrate ways of using the obtained results.

Abstract: Within the linear theory of elastic-plastic body we carried out the modeling of technological process of annealing: slow heating stage, the holding stage under constant temperature and slow cooling step. Holding stage is simulated with consideration of creeping properties of materials. Boundary value problems are examined and patterns responsible for the removal of residual stresses at temperature influence are described. An analytical solution is found. It is proved that the holding stage is essential for describing the process of residual stress relief.

Abstract: The paper presents the numerical research of conjugate heat exchange and hydrodynamics in the motion of viscous fluid in the technological elements of energy systems (cavities) in the consideration of its damage. The hydrodynamic figure of the motion viscous fluid and its temperature fields for solid and fluid phases obtained. The model parameters influence on the motion of the heat carrier and the distribution of temperatures in two phases have been studied. The impact of dynamic parameters and geometrical characteristics for the formation of contours generating craters studied.

Abstract: A direct approach of the boundary element method for treating 3-D boundary-value problems of poroelastodynamics is considered. Biot’s material model with four unknown base functions is used. Computational results for the surface responses of displacements and pore pressures as functions of a force acting on a half-space weakened by a cavity are presented.

Abstract: In this article the time change automatically balanced unbalanced rotor automatic ball balancing devices is considered. The calculation of original differential equations is made with numeral calculation using the Runge-Kutt method. The time dependence of the transition process of the balancing process from the parameters of the automatic balancing device is obtained.

Abstract: This article provides the results of the study of the strain-stress state of two corrugated shell structures. Geometric modeling was conducted in “Autodesk Inventor” system. Corrugated shell structures were studied with the help of engineering analysis systems MSC.Patran and MSC.Marc. As a result of the study an optimal type of corrugated shell structure was chosen.