The monograph text is based on lectures delivered by author during many
years for students of Applied Iechanics Department of Bauman Ioscow
State Technical University. The monograph includes also analitical
results of scientific research obtained in collaboration with industry.
Progress in developing new equipment has called for a better understand-
ing of the physical peculiarities pertaining to the action of designed
structures in real conditions. This is necessary for increasing the
accuracy of the analysis and making these structures more reliable. It
has been found that classical determined perturbations are not principal
and that determinism-based methods of classical mechanics prove
insufficient for understanding and explaining physical effects that
arise at the operation of instruments located on moving objects, the
vibration of rocket engines, the motion of a vehicle, and the action of
wind and seismic loads. Therefore the necessity arose for devising a new
physical model to analyze these dynamic processes and, in particular,
for creating a new mathematical apparatus that would allow us to take
into account non-deterministic external excitations. The theory of
random processes that had been developed well enough as applied to
problems of radio engineering and automatic control, where the effect
produced by random excitations appeared to be commensurable with that of
deterministic excitations and where the ignoring of the random ex-
citations would bring about incorrect results, became such an apparatus.