Nonlinear effects in deformation of filled elastomers with nanodimensional fillers

Various nonlinear effects manifesting themselves in the deformation of filled elastomers are analyzed, and the advantages and restrictions in the use of several constitutive relations proposed to describe the nonlinear viscoelastic behavior of the materials under study are discussed. We also note that further development of models of nonlinear deformation of filled elastomers under finite strains, which would permit describing their deformation properties more completely, is highly desirable.     

Investigation of impact resistance of multilayered woven composite barrier impregnated with the shear thickening fluid

Dynamic properties of the Shear Thickening Fluid (STF) are studied. Two series of tests by the Split Hopkinson Pressure Bar method were carried out to determine the dynamic bulk and shear properties of STF. The hypothesis about the possibility to describe STF behavior by a Newtonian fluid model in the characteristic range of strain rates is confirmed. A simplified mathematical model of the STF is then formulated for the use in computer simulation of ballistic impact tests of multilayered composite protective shells. The effectiveness of the STF impregnation for improvement of ballistic impact characteristics of Kevlar woven fabrics is confirmed. It is concluded that the role of the contact conditions between STF and Kevlar basis in the process of increasing the energy absorption capacity of Kevlar-STF barrier is significant, noting that the mechanism of contact interaction between STF and Kevlar basis can be described by viscous friction law, i.e., the STF behaves almost as a rigid body during the interactions with the solids, while it normally behaves as a fluid. It is also established that the STF impregnation of protective shells with titanium framework not only increases the absorption capacity of the whole package but also reduces the deflection of the metal base.     

Effect of reinforcing elements on the deformation and strength of glass-reinforced plastics in tension

The problem of extension of a bar of constant cross section containing reinforcing elements in the form of rods arranged parallel to the generators of the lateral surface is considered. A solution is obtained by the Muskhelishvili method. This solution is analyzed and approximate formulas are proposed for the averaged characteristics of materials (especially glass-reinforced plastics) as a function of the relative contents and mechanical properties of the components. The formulas obtained closely reflect a number of known experimental facts.Mekhanika Polimerov, Vol. 1, No. 2, pp. 104–113, 1965     

Thermal degradation and combustion behavior of the polyethylene/clay nanocomposite prepared by melt intercalation

Studies of thermal and fire-resistant properties of the polyethylene/organically modified montmorillonite (PE/MMT) nanocomposites prepared by means of melt intercalation are discussed. The sets of the data acquired with the aid of non-isothermal TG experiments have been treated by the model kinetic analysis. The extra acceleration of thermal-oxidative degradation of the nanocomposite which has been observed at the first stage of the overall process has been analyzed and is explained by the catalytic effect of the clay nanoparticles. The results of cone calorimetric tests lead to the conclusion that char formation plays a key role in the mechanism of flame retardation for nanocomposites.     

On the role of branched-chain (autocatalytic) reactions in the carbonaceous feedstock pyrolysis kinetics at oscillating temperature

A kinetic model of flash pyrolysis as a branched-chain process was presented. It was shown that, under unsteady temperature conditions, the branched-chain process significantly enhances carbonaceous feedstock processing.