The non-linear deformation and stability of elliptical cylindrical shells under transverse bending

A finite-element formulation of the solution of problems of the stability of non-circular cylindrical shells taking into account their bending moments and the non-linearity of their precritical stress-strain state in proposed. Explicit expressions for the displacements of the elements of non-circular cylindrical shells as rigid bodies are derived by integration of the equations obtained by equating the components of the linear strains to zero. These expressions are used to construct shape functions of an effective quadrilateral finite element of the natural curvature. An effective algorithm is developed for investigating the non-linear deformation and stability of the shells. The stability of a cylindrical shell of elliptical cross-section under transverse bending is investigated. The influence of the ellipticity and non-linearity of the deformation on the shell's stability is determined. The results of the analysis are compared with experimental data.     

Formation of space charge in high-resistivity materials under the action of intense pulsed electron beams

Results are presented of the experimental investigation and the theoretical laws of the formation of space charge in dielectrics irradiated with intense pulsed electron beams. It is shown that the kinetics of space charge accumulation and the character of electric breakdowns exhibit peculiarities not found in analogous processes involving irradiation with low-intensity electron beams.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 46–50, September, 1985.     

Acoustic measurements in rubberlike polymers during compressive deformation

Problems associated with the method of measurement of acoustical properties of viscoelastic materials and the influence of various external factors (temperature, pressure) on these materials have been examined. The results of measurements of propagation speeds and damping coefficients of waves of the sonic and ultrasonic regions in resins are given for discrete excitation frequencies and during simultaneous static action on the specimen. It is shown that uniaxial compression of the resin results in the appearance of dispersion of the dynamic elastic modulus. A possible explanation of this phenomenon is suggested.Dnepropetrovsk Civil Engineering Institute. Translated from Mekhanika Polimerov, No. 1, pp. 149–156, January–February, 1974.