On the effect of the anisotropic dry friction and the deformed state of tires on the shimmy initiation

The shimmy theories based on the Keldysh assumption can be easily implemented analytically and are still quite efficient for the preliminary analysis of the stability of steady state rolling regimes with no slip and spin of tires. On the other hand, such a shimmy theory uses the non-holonomic rolling model, therefore it is inconsistent with unsteady rolling regimes characterized by the non-vanishing sliding and spin. The qualitatively different model accounting the dry friction effect on the stability of motion is constructed on the groundwork of the coupled dry friction theory. This model has shown its’ applicability to some practical problems of engineering design even if a wheel is assumed to be rigid. Here the improved model accounting for the tire deforming, the complex contact pressure distribution, an the anisotropy of the dry friction coefficient in case of the combined kinematics is presented

Numeric-analytical methods of the coefficients definition of the rolling friction model of the pneumatic aviation tire

A new approximate models of the tire rolling accounting for coupled longitudinal and lateral sliding as well as the spinning and the deformed state resulting in elastic forces were proposed in previous works [1-7]. The main goal of this investigation consists in the development of the numeric-analytical methods of these models coefficients definition

A Method of Parameters Identification for the Coupled Dry Friction Model for Pneumatic Tires

The theory of multi-component dry friction accounting for the coupled kinematics of relative motion in finite contact spots is applied to the modelling of pneumatic tires. The analytical models of the combined dry friction accounting for the anisotropy of the dry friction factors as well as the distribution of the contact pressure close to the real one are introduced. The exact integral relationships between the dry friction force and torque and the generalized velocities, i. e. the speed of sliding and angular velocity of spinning, appears as a result of integration over the contact spot and are too complex to be implemented analytically into the engineering practice. The proposed approximate models are based on the fractional approximations and could be interpreted as rheological models with low number of constitutive constants. These constants could be identified after the solution of some specific inverse problems with input data given by the diagrams of the dry friction forces and torque obtained as a result of simple physical tests. Here these inverse problem are formulated and solved using the perturbed benchmark solutions of the corresponding direct problems with the factors obtained after the numerical solution of the contact problem for the heterogeneous pressurized tire. The possibility of stable solution for the inverse problems on the basis of the proposed approach is shown. The presented models as well as the method if constitutive constants identification could be applied for more detailed investigation of unsteady rolling regimes of pneumatics which are characterized by the non-vanishing sliding and spin

Socialization of economy in the conditions of continuous wellbeing’s innovative model

Socialization of economy is connected with a basic change of the person’s position in production and her or his wellbeing in society. Radical activation of the human capital appears in creative participation of the worker in production and promotes growth of continuous wellbeing and fully reveals its intellectual, moral, creative qualities. In this case the reproduction of the worker appears as all-round development of the personality; as expanded reproduction expressed in equipment by her or his knowledge, growth of her or his creative abilities and increase of moral. The solution of the technological freedom’s problem of the worker from a status of an appendage of an extensively developed machine device consists in a deep quality leap in development of productive forces on the basis of achievements of scientific and technical progress and formation of a new model of economic wellbeing of the person. There is an approach to the analysis of technologies socialization in innovative economy in the process of work, in which the person and the equipment are in indissoluble functional unity. This approach allows investigating regularities of development of technologies together with the content of work, which is qualitatively transformed and obtains key characteristics, such as humanization, serviceability and socialization

On the equations of the analytical dynamics of the quasi-3D plate theory of I. N. Vekua type and some their solutions

The plate theory of Nth order is constructed on the background of the Lagrangian variational formalism of analytical dynamics of continuum systems and the dimensional reduction approach of I. N. Vekua – A. A. Amosov. The plate model is defined within the configuration space, the set of field variables, and the Lagrangian density. The field variables are determined by the coefficients of the biorthogonal expansion of the spatial displacement vector field with respect to the dimensionless normal coordinate. The dynamic equations are derived as Lagrange equations of the second kind of the two-dimensional continuum system. The dynamics of the plane elastic layer is considered as an example, the normal wave propagation is described on the basis of refined plate theories of various orders, and the convergence of approximate solutions to the exact solution of the three-dimensional elastodynamics problem is analyzed for different wavenumbers

Molecular epidemiological study of clinical cases of acute hepatitis E in Belarus

Relevance. The frequency of occurrence of anamnestic antibodies to the hepatitis E virus (HEV) in the general population of the Republic of Belarus is 7.3%, which is clearly not consistent with the low incidence of hepatitis E (HE). Most of primary HEV infections remain undiagnosed. The intensive epidemic process of HEV in the Belarusian population is hidden. Conducting epidemiological studies, including genotyping of HEV sequences isolated on the territory of the republic, makes it possible to more accurately characterize the sources of HEV infection and the mechanisms of its transmission. Aim molecular epidemiological study of two cases of acute hepatitis E detected in patients from Belarus. Materials and methods. During 20212022, samples of biological material were obtained from two patients undergoing treatment with an established diagnosis of acute hepatitis E. Serum samples were tested to detect antibodies to HEV using enzyme immunoassay, HEV RNA was detected in fecal samples using nested RT-PCR. The nucleotide sequence was determined by an automatic sequencer using the Sanger method. Analysis of nucleotide sequences, their genotyping, and calculation of evolutionary distances were performed using MEGA X software. Results. The HEV sequence isolated from a pregnant woman who had an epidemiological episode of alimentary contact with raw pork meat is clustered into a common phylogenetic clade with HEV sequence obtained from the patient from Belarus with a history of kidney transplantation and HEV sequences isolated from a domestic pigs. The HEV sequence isolated from a patient with a history of travel to Pakistan belongs to the HEV genotype 1 and joins a clade of HEV sequences isolated in Pakistan, India, Nepal and Mongolia

ON HAMILTONIAN FORMULATIONS AND CONSERVATION LAWS FOR PLATE THEORIES OF VEKUA-AMOSOV TYPE

Some variants of the generalized Hamiltonian formulation of the plate theory of I. N. Vekua – A. A. Amosov type are presented. The infinite dimensional formulation with one evolution variable, or an “instantaneous” formalism, as well as the de Donder – Weyl one are considered, and their application to the numerical simulation of shell and plate dynamics is briefly discussed. The main conservation laws are formulated for the general plate theory of Nth order, and the possible motion integrals are introduce

Implementation of analytical models of the anisotropic combined dry friction in problems of pneumatics’ dynamics

An implementation of the theory of multi-component dry friction in some engineering problems of pneumatics’ dynamics is proposed. The main attention is devoted to the construction of analytical models of the combined dry friction accounting for the anisotropy of the dry friction coefficients and the real distribution of normal and tangent contact stresses. These models are applied for more detailed investigation of unsteady rolling regimes of pneumatics which are characterized by the non-vanishing sliding and spin

Numeric-analytical methods of the coefficients definition of the rolling friction model of the pneumatic aviation tire

A new approximate models of the tire rolling accounting for coupled longitudinal and lateral sliding as well as the spinning and the deformed state resulting in elastic forces were proposed in previous works [1-7]. The main goal of this investigation consists in the development of the numeric-analytical methods of these models coefficients definition

Socialization of economy in the conditions of continuous wellbeing’s innovative model

Socialization of economy is connected with a basic change of the person’s position in production and her or his wellbeing in society. Radical activation of the human capital appears in creative participation of the worker in production and promotes growth of continuous wellbeing and fully reveals its intellectual, moral, creative qualities. In this case the reproduction of the worker appears as all-round development of the personality; as expanded reproduction expressed in equipment by her or his knowledge, growth of her or his creative abilities and increase of moral. The solution of the technological freedom’s problem of the worker from a status of an appendage of an extensively developed machine device consists in a deep quality leap in development of productive forces on the basis of achievements of scientific and technical progress and formation of a new model of economic wellbeing of the person. There is an approach to the analysis of technologies socialization in innovative economy in the process of work, in which the person and the equipment are in indissoluble functional unity. This approach allows investigating regularities of development of technologies together with the content of work, which is qualitatively transformed and obtains key characteristics, such as humanization, serviceability and socialization