On Strong and Weak Discontinuities of the Coupled Thermomechanical Field in Micropolar Thermoelastic Type-II Continua

The present study is devoted to problem of propagating surfaces of weak and strong discontinuities of translational displacements, microrotations and temperature in micropolar (MP) thermoelastic (TE) type-II continua. First part of the paper is concerned to discussions of the propagating surfaces of strong discontinuities of field variables in type-II MPTE continua. Constitutive relations for hyperbolic thermoelastic type-II micropolar continuum is derived by the field theory. The special form of the first variation of the action integral is used in order to obtain 4-covariant jump conditions on wave surfaces. Three-dimensional form of the jump conditions on the surface of a strong discontinuity of thermoelastic field are derived from 4-covariant form. Problems of propagation of weak discontinuities in type-II MPTE continua are discussed too. Geometrical and kinematical compatibility conditions due to Hadamard and Thomas are used to study possible wave surfaces of weak discontinuities. It is shown that the surfaces of weak discontinuities can propagate exist without weak discontinuities of the temperature field

DETERMINATION OF AIR RESISTANCE ACCORDING TO VEHICLE’S RUNNING-DOWN

Two methods of calculating the vehicle’s drag coefficient CX according to the road dece-leration value, according to the road decleration value known and suggested by the authors, are com-pared. Evaluation criteria – the ratio of the calculated CX to the declared by the manufacturer. The new method is somewhat more accurate and has no speed limit. The obtained average evaluation criterion 1,16...1,20 is much higher than cited in the literature of 1,05...1,10