Problems of the theory of deformation of polymeric materials under complex loading

Research on problems of the theory of deformation of polymeric materials under complex loading based on a synthesis of creep theories and the local strains theory is reviewed.Presented at the 2nd All-Union Conference on Polymer Mechanics, Riga, November 10–12, 1971.M. V. Lomonosov Moscow State University. Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No. 3, pp. 434–443, May–June, 1972.     

Physical source realization of complex source pulsed beams

Complex source pulsed beams (CSPB) are exact wave-packet solutions of the time-dependent wave equation that are modeled mathematically in terms of radiation from a pulsed point source located at a complex space-time coordinate. In the present paper, the physical source realization of the CSPB is explored. This is done in the framework of the acoustic field, as a concrete physical example, but a similar analysis can be applied for electromagnetic CSPB. The physical realization of the CSPB is addressed by deriving exact expressions for the acoustic source distribution in the real coordinate space that generates the CSPB, and by exploring the power and energy flux near these sources. The exact source distribution is of finite support. Special emphasis is placed on deriving simplified source functions and parametrization for the special case where the CSPB are well collimated.     

Stress Concentration Near Stiff Cylindrical Inclusions under Anti-Plane Shear Loading

Doklady Physics - Analytical solutions for the problems of stress concentration near cylindrical inclusion with circular or elliptical cross section under the anti-plane shear loading are...     

Chloroauric Acid Effect on Electrical Properties of SWCN Networks Synthesized with Anthracite Addition Using Aerosol CVD Method

Russian Physics Journal -     

Refined Stress Analysis in Applied Elasticity Problems Accounting for Gradient Effects

Doklady Physics - An extension of the approaches to gradient theories of deformable media is proposed. It consists in using the fundamental property of solutions of the elasticity gradient theory,...     

Supercritical Deformation and Fracture of Bodies with Concentrators under Plane Stress State Conditions

The paper deals with experimental studies of inhomogeneous strain fields with regions of supercritical behavior of the material in the case of extension of plane specimens of steel 20 with concentrators of different geometry by using the method of digital image correlation. The use of a video system permits obtaining experimental data about the distribution of the fields of longitudinal, transverse, and shear components and the strain intensity. The previously considered criteria for the deformation process transition to the supercritical stage for different types of the stress–strain state were used to distinguish the regions of supercritical behavior and to analyze the evolution of the strain and temperature fields in their stable development.     

Effect of external influences on the structural and dynamic parameters of polyhydroxybutyrate-hydroxyvalerate-based biocomposites

The EPR probe, DSC, and WARDX methods are applied to study the molecular dynamics and structure of 3-hydroxybutyrate-3-hydroxyvalerate copolymer (PHBHV, 5 mol %) and its mixtures with segmented polyester urethane (SPEU) upon ozone oxidation and hydrothermal treatment. It is shown that time-limited (3 and 5 h) treatment of the mixed compositions with water at 40°C has no noticeable effect on the dynamics of rotation of the probe (EPR) and the crystallinity of PHBHV (DSC). However, hydrothermal treatment at 70°C causes an increase in the molecular mobility of the probe in the system, accompanied, according to XRD and DSC analyses, by increases in the degree of crystallinity and density of PHBHV crystallites. The temperature of fusion of mixed compositions also increases. During ozonation, the mobility of the probe slows gradually in PHBHV all the time, whereas in mixed compositions, a slowdown is observed only up to 3 h of oxidation time, after which, up to 5 h of ozonation, the mobility increases, along with decreases in the fraction of the amorphous phase and in the density of the crystallites.