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Martinovs, Andris
Preferred name
Martinovs, Andris
Alternative Name
Andris Martinovs
Martinovs, A
Email
andris.martinovs@rta.lv
ORCID
Scopus Author ID
57217029083
Researcher ID
GQW-2280-2022
Research Output
Now showing 1 - 5 of 5
- PublicationAGING, FATIGUE AND DURABILITY OF RUBBER VIBRATION ISOLATION ELEMENTS(2017)
; Svetlana SokolovaThis paper deal with shock and vibration insulators, which usually are performed from the elastomeric (rubber-like) materials. Elastomeric materials give many engineering advantages due to their capability of absorbing input energy much better than engineering materials, high elasticity, good dynamic properties, low volume compressibility, a linear relationship between stress and strain up to strain of 15% ÷ 20%, resistance to aggressive environmental factors. Elastomeric materials are widely used in machine building, shipbuilding, civil engineering, aviation and aerospace as compensation devices, vibration dampers, shock absorbers. Laminated elastomers, consisting of interleaved thin layers of elastomer and rigid reinforcing layers are also successfully used as bearing, joints, dampers, compensating devices, shock-absorbers. Such structures have many advantages: ability to endure high stress (>200 MPa), ease of maintenance, non- necessity for lubrication, vibration and noise reduction, ability to work in a very dirty, dusty, abrasive environment. The disadvantage of elastomeric material are aging, i.e. changing its properties over time. In this paper the influence of aging of elastomeric materials on the damping properties of shock absorbers is considered based on the mechanical models of elastomers - Maxwell and Burgers modes. Fatigue endurance, i.e. the ability to withstand mechanical actions for a long time is studied based on experiments on dynamic shear with laminated rubber-metal structures. The experiments show that such structures have a very high fatigue life - up to 100 million cycles.Scopus© Citations 5 - PublicationSpecifics of behavior and calculation of elastomeric shock absorber under impact loading(2018)
; Vladimirs GoncaIn 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 - PublicationInfluence of rubber ageing on damping capacity of rubber vibration absorber(2018)
; The vibration dampers, shock absorbers, seismic isolation, bearing seals, compensation devices are widely applied in civil engineering, machine manufacturing and shipbuilding, aviation and aerospace engineering. For these details fabrication elastomeric materials are used. Rubber and rubber-like materials (elastomers) have the capability of absorbing input energy much better than other engineering materials. Elastomeric materials give many engineering advantages due to their high elasticity, good dynamic properties, low volume compressibility, a linear relationship between stress and strain at small and middle deformation, resistance to aggressive environmental factors. The disadvantage of elastomeric materials is ageing, i.e. changing their mechanical properties over time and lowering their operational capability. In given paper the influence of ageing of elastomeric materials on the damping properties of shock absorbers is considered based on the mechanical models of elastomers - Maxwell and Burgers modes.Scopus© Citations 6 - PublicationEXPERIMENTAL STUDYING OF MECHANICAL-AND- PHYSICAL PROPERTIES OF RUBBER DURING AGEING(2019)
; Elastomeric materials, both natural rubber and synthetic, are widely used in industry and civil engineering, due to their unique properties: high elasticity, low volume compressibility, capability to absorb and dissipate input energy, a linear relationship between stress and strain up to strain of 15% ÷ 20%, resistance to aggressive environmental factors. Different kind of compensation devices, vibration dampers, shock absorbers are fabricated from rubber materials.At the same time the elastomeric materials nonreversible change their properties over time, this disadvantage is called ageing.In given paper the results of experimental studying of the influence of aging on the physical-and-mechanical properties of polyurethane rubber is presented. The samples of cylindrical form were prepared from soft flexible polyurethane rubber Xenias PX30 and subjected to the artificial ageing. Accelerated aging of samples was fulfilled in accordance with European standard ISO 188:2011 (Rubber, vulcanized or thermoplastic - Accelerated ageing and heat resistance tests).The changing of volume, Shore A hardness, elastic rebound coefficient and static elasticity modulus under compression were investigated. Experiments showed the volume decrease, hardness shore increasing, elastic rebound increase and compression modulus under static loading increasing. This data are necessary for correct designing of the compensation devices to provide their working properties during all service life. - PublicationTorsional, compression and shear stiffness of thin-layer rubber-metal spherical joint-hinge(2017)
; Vladimirs GoncaIn this paper laminated elastomeric bearings (composite of thin elastomer and metal layers) are considered. This type of bearings or joint-hinge has many advantages because of ease of maintenance; ability to work in a very aggressive environment, low cost and vibration damping capability. The geometric shape of such bearing may be planar, cylindrical, conical, spherical and other, given work deals with spherical thin-layered rubber-metal bearings. Operating of such device depends on many factors that must be considered on the design stage: parameters of the elements must be selected properly. The most important parameter is stiffness – dependence between imposed force and received deformation. In this work torsional, compression and shear stiffness of laminated bearings was defined for the testing specimens by experiments and torsional stiffness was received analytically. Both methods show good enough coincidence.