Svetlana Polukoshko

FDM Prototype Experimental Research of Processing Parameter Optimization to Achieve Higher Tensile Stress

Fused Deposition Modeling (FDM) is one of most common ways of rapidly producing a part. Heated material (most commonly – plastic) is used to extrude it through a nozzle and deposit on a surface layer by layer until the part is fully produced. FDM has become one of the most popular in rapid production area due to its low cost, available materials and versatility.Due to fact that part is made layer by layer and each additional layer is deposited on top of a layer that is already a little below material melting point, part maintains different mechanical properties in various directions. These varying mechanical properties affect the part usability in practical applications. Critical point is tensile strength.The objective of this paper is to research optimal processing parameters for FDM prototyping to improve tensile strength. Several rapid prototype models (tensile test samples) with various geometry of longitudinal reinforcement channels were built. As reinforcing material, the epoxy resin was used, because it has higher tensile strength when solid and allows filling channels with various geometry. All made samples were tested for tensile strength. Experiment was carried out to confirm the effectiveness of this approach. From the results, it is found how different amount of epoxy resin affects part tensile strength.

Vibration Damping Using Laminated Elastomeric Structures

The work considers using a multilayer elastomeric package for the vibroisolation of engineering constructions under the action of periodic vibration. The multilayer elastomeric package is located between the protected object and a vibrating base; it consists of alternating thin metallic and elastomeric layers jointed by vulcanization or gluing. The paper discusses flat rubber-metal elements of circular shapes with reinforcing steel layers and describes kinematic excitation directed flatwise. The analytical expression of the characteristics of the compression stiffness of the plane multilayered elastomeric structure is derived on the basis of the variational principle, and metallic plates-layers are assumed to be perfectly rigid. An analytical solution was confirmed by experimental data. The fitted equation for “force-displacement” was derived and used in the equation of motion on of the protected object.

Adhesive Layer Influence on Compressive and Tension Stiffness of Thin-Layer Rubber-Metal Elements

The technique of “force–displacement” stiffness characteristics calculation for thin-layer rubber-metal damping devices is presented in this work. It is proposed to take into account adhesive layers and deformation of non-elastomeric layers working under tension and compression. A variational method of linear theory of elasticity for weakly compressible materials is used for calculations. The received dependences allow explaining nonlinearity of “force–displacement” stiffness characteristics and various behavior of glued rubber-metal device under tension and compression, observed in experimental investigations.

Nonstationary Processes Studying Based on “Caterpillar”—SSA Method

This paper deals with “Caterpillar”-SSA method—a new powerful model-free method of time series analysis and forecasting. It allows to decompose the nonstationary time series into trend, periodic components (sum of elementary harmonic), noise (random components) and to forecast subsequent behavior of system, if separability condition of time series and possibility of reverse synthesis of individual elements are fulfilled. This paper shows application of this method for random and nonlinear vibrations study on the example of building element vibration under seismic action.

Rigid Body Motion Conversion due to Collision

The impact phenomenon may be used for task-oriented changing of rigid body motion. When moving body encounters with some obstacle all parameters of motion are changing as a result of impact and trajectory and type of motion are also changing. In this work the conversion of translatory motion of prismatic rigid body into plane or rotation and conversion of plane motion of cylindrical body due to impact are considered. The conditions of conversion of one type of motion into another and parameters post-impact motion are studied. Problems are solved in the framework of rigid body motion, using rigid body impact theory. Studying of such phenomena is important for location of parts on industrial conveyors, feeders, etc.

Estimation of Parameters of Soil Vibration Due to Impact Loading

The results of the finite element analysis of impact action on structure and soil are presented in this work. Finite element analysis is executed by means of Plaxis program, which enables to take into account soil – structure interaction. The next problems are discussed: vertical impact on concrete foundation, modeled with axisymmetric models, and horizontal impact on the sheet-piling and on the concrete bridge pier, simulated with plane strain models.