Contact Problems for Prestressed Elastic Bodies and Rigid and Elastic Punches

Contact problems for prestressed bodies and rigid and elastic punches are discussed. The influence of the prestresses on the contact characteristics is analyzed numerically     

On a Modern Philosophy of Evaluating Scientific Publications

Current approaches to the citation analysis of scientific publications are outlined. Science Citation Index, Impact Factor, Immediacy Index, and the selection procedure for Essential Science Indicators—a relatively new citation analysis tool—are described. The new citation evaluation tool has yet not been discussed adequately by mechanicians __________ Translated from Prikladnaya Mekhanika, Vol. 41, No. 10, pp. 3–11, October 2005. Prepared in the context of events planned for the World Science Day for Peace and Development, celebrated each November 10, in compliance with a resolution of the 37th Session of UNESCO General Conference.     

Stress state of a composite shell with a sizable opening

The stress-strain state of a nonshallow cylindrical shell of a composite material is investigated. The shell is weakened by a circular hole and loaded with internal pressure. For solving the problem, the variational-difference method is used. The calculations are carried out for an orthotropic shell with a sizable hole, with account of the reduced shear stiffness of the material.Translated from Mekhanika Kompozitnykh Materialov, Vol. 41, No. 1, pp. 49–56, January–February, 2005.     

Establishing the Fundamentals of the Theory of Stability of Mine Workings

The fundamentals of the theory of stability of mine workings are analyzed. The theory is based on the linearized three-dimensional theory of stability of deformable bodies. Some results on horizontal and vertical mine workings and on underground closed cavities are analyzed     

Theoretical description of a delamination mechanism in fibrous micro- and nanocomposites

Theoretical analysis and numerical modeling of unidirectional fibrous micro- and nanocomposites carried out based on the theory of two-component mixture testify that the second mode of a transverse wave propagating along and polarized across the fibers may produce, at high frequencies, a kinematical pattern critical for the strength of the composite material. While the wave propagates, the components (matrix and fibers) of the mixture oscillate in antiphase. This fact may be critical because such oscillations generate forces separating the matrix and fibers, which is typical for the delamination of composite materials.Translated from Prikladnaya Mekhanika, Vol. 40, No. 10, pp. 78–87, October 2004.     

Features of plane wave propagation along the layers of a prestrained nanocomposite

Features of the propagation of longitudinal and transverse plane waves along the layers of nanocomposites with process-induced initial stresses are studied. The composite has a periodic structure: it is made by repeating two highly dissimilar layers. The layers exhibit nonlinear elastic behavior in the range of loads under consideration. A Murnaghan-type elastic potential dependent on the three invariants of the strain tensor is used to describe the mechanical behavior of the composite constituents. To simulate the propagation of waves, finite-strain theory is used for developing a problem statement within the framework of the three-dimensional linearized theory of elasticity assuming finite initial strains. The dependence of the relative velocities of longitudinal and transverse waves on two components of small initial stresses in each layer and on the volume fraction of the constituents is studied. It is established that there are thickness ratios of layers in some nanocomposites such that the wave velocities are independent of the initial stresses and equal to the respective wave velocities in composites without initial stresses __________ Translated from Prikladnaya Mekhanika, Vol. 43, No. 4, pp. 3–26, April 2007.     

Fracture of cylindrical shells with cracks in tension

In practice, cracks may frequently be introduced in structural components during the course of the technological manufacturing and service. Studies concerning the strength prediction of structures with cracks are therefore of considerable importance. During the fracture process of thin-walled structure elements, material local to the crack may buckle. The fracture characteristics may be affected considerably. Both theoretical and experimental studies of this problem were made for plates [1]. In this work, experimental results are presented for the deformation and fracture of cylindrical shells with cracks.     

Model system for targeted drug release triggered by immune-specific signals

A new sense-and-act system was realized by integrating a biocatalytic/bioaffinity electrode responding to immune signals represented by an antibody and a polymer-modified electrode loaded with drug-mimicking species. The release of the drug-mimicking species was achieved specifically in response to a signal antibody, thus demonstrating for the first time an immune-induced drug-releasing process. The present approach promises new options for future applications in controlled drug release and personalized medicine.