Vladimirs Gonca

Car rollover collision with pit corner

The paper presents a theory of body collision with pit corner. The theory can be successfully applied in approaching tasks coping with the orientation of details in technological processes and control systems, the motion of elements in mechanisms having a gap, collisions in motion of different sport objects, the analysis of car accidents etc. The applied theory deals with car motion after collision with a specific obstacle i.e. pit corner. The study is based on linear and angular momentum theorems and two restitution coefficients of normal impulse from both sides of the obstacle. The obtained results can be used for assessing road accidents in case of car collision with one or more obstacles. The object of contact may involve hitting a plane foundation, the ditch and edging of a highway or a rock in the field.

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.