Martinovs, Andris

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Martinovs, Andris
Alternative Name
Andris Martinovs
Martinovs, A
Main Affiliation
Email
andris.martinovs@rta.lv
ORCID
Scopus Author ID
57217029083
Researcher ID
GQW-2280-2022

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  • Publication
    Specifics of behavior and calculation of elastomeric shock absorber under impact loading
    (2018)
    Svetlana Polukoshko
    ;
    Martinovs, Andris 
    ;
    Vladimirs Gonca
    In this paper the important for the design of shock-absorbers case of a perfectly rigid body impact with a viscoelastic incompressible body is considered. Mathematical apparatus for calculating the parameters of impact of a rigid body with a highly- elastic rod is developed, taking into account the peculiarities of the behavior of elastomers under fast loading. An analytical solution was obtained for longitudinal impact on a vertically disposed rod. The solution was fulfilled by means of the Bubnov- Galerkin variational method, reducing the problem to solving of the integro-differential equation for given boundary and initial conditions The solution is received for the exponential relaxation kernel for the Maxwell model of a highly-elastic material, it describes the process of damped longitudinal vibration, taking into account the effect of creep caused by the instantaneous impact loading. Based on the equation of vibratory motion the equations of velocity and acceleration are received, which are used for stress-strain behavior analysis of rubber damper. A numerical example of an axial tensile impact on a viscoelastic shock-absorber in the form of a cylindrical rod is given with the plots of time dependence of displacement, velocity, and acceleration of the impact end of the rod are provided, the possibility of using them for analyzing the shock absorber is demonstrated.
    Scopus© Citations 1
  • Publication
    Determination constants of 4-element reological model with rebound resilience method
    (2017)
    Martinovs, Andris 
    ;
    Svetlana Polukoshko
    ;
    Elvijs Apeinans
    ;
    Zaicevs, Edgars 
    In this paper an express-method and equipment for experimental determination of the 4-element rheological model constants (2 elastic modulus, 2 viscosity coefficients) for elastomers are developed. The method is based on rebound of falling hammer against an elastomer material. A mathematical model for describing this collision is elaborated and an algorithm for determination of the constants of the model was developed and realized in Matlab software. Time necessary for determination of the constants is until 5 minutes. It gives an opportunity to significantly accelerate the design and production process of elastomer-metal vibration isolator prototypes with defined parameters of stiffness and damping. The method allows to trace displacement, velocity and acceleration of the metal parts of the shock absorber throughout the collision; this may be realized with Matlab or an analogical program of numerical integration. For forecasting of the mechanical properties of the shock absorber during a long period (considering the aging of elastomer) it is necessary to know the rheological model parameter dependence on time, temperature, energy input and other factors; the proposed method allows to significantly accelerate these experimental studies.
    Scopus© Citations 2