Effect of boundary-layer processes on the strength of glass-reinforced plastics

It is shown experimentally that the strength of glass-reinforced plastics is determined by the properties of the resin close to the fibers; these depend on the structure and chemical composition of the fiber surface. A study is made of the effect of modification of the glass fiber on curing conditions in the layer next to the fiber for a number of resins (K9 silicone resin, ED-6 epoxy resin, polyacrylate-911, and furfural PF resin).Mekhanika polimerov, Vol. 1, No. 1, pp. 26–35, 1965     

Effect of aggressive media on the fatigue life of plastics

The dependence of fatigue life on concentration has been obtained for PVC and polystyrene exposed to the action of acetone solutions. As the mechanical stress increases, the role of the aggressivity of the medium diminishes, and its corrosion activitya tends to a minimum (a=1). When a polymer is exposed to the action of a binary liquid, both of whose components are aggressive, a transition region is observed on the log 1/-log C curve. In this region the fracture rate increases sharply.Mekhanika Polimerov, Vol. 4, No. 3, pp. 489–493, 1968     

Effect of hydrostatic pressure on the density of various plastics

It is shown that application of hydrostatic pressure causes an increase in the density of ebonite but practically no change in the density of polyethylene, kapron (nylon-6), PVC, plexiglas, and FKP-1. Uniaxial compression of some materials first increases their mean density, then, at fairly high strain, causes the density to decrease. For the majority of the materials examined, the rate of this reduction in density decreases in the simultaneous presence of hydrostatic pressure.Mekhanika Polimerov, Vol. 2, No. 3, pp. 355–358, 1966     

Effect of extended storage on the mechanical properties of reinforced plastics

The effect of storage time (6–10 years) on the mechanical properties of KAST-V glass laminate, textolite, and SVAM glass-reinforced plastic has been experimentally investigated.Moscow Lomonosov State University. Translated from Mekhanika Polimerov, No. 3, pp. 556–558, May–June, 1969.     

Effect of loading frequency on the fatigue strength of glass plastics

A method of fatigue-testing glass-plastics in the frequency range 1000–6000 Hz is presented together with some typical results. On the basis of the experimental results it is recommended that fatigue tests on glass plastics of the technological sample type should be carried out at high frequencies.     

Effect of residual stresses on the strength of oriented glass-reinforced plastics

The effect of structural residual stresses on the strength of a glass-reinforced plastic loaded along and across the fibers is investigated. It is established that the residual stresses lead to an increase in the strength of the glass-reinforced plastic across the fibers and to cracking of the polymer matrix in tension along the fibers, but have practically no effect on the combined deformation of the matrix and the fibers in compression.Moscow Ordzhonikidze Aviation Institute. Translated from Mekhanika Polimerov, No. 3, pp. 475–480, May–June, 1969.     

Effect of stress ratio on the fatigue strength of organic plastics

Conclusions Experimental fatigue curves of a unidirectional organic plastic are obtained for a number of asymmetry factors and diagrams of the limiting cycle stresses are constructed for a load in the direction of the fibers and across the fibers, and for in-plane shear of a layer. The simplest methods of approximating the calculated diagrams are tested. It is shown that the method of layer-by-layer analysis of fatigue failure makes it possible to construct limiting-stress diagrams for a laminar oblique-ply composite with an accuracy acceptable for engineering calculations, proceeding from the same analysis as for an individual layer.Translated from Mekhanika Kompozitnykh Materialov, No. 3, pp. 421–429, May–June, 1991.     

Effect of hydrostatic pressure on mechanical properties of plastics

The effect of hydrostatic pressure on the elastic and strength properties of plastics is investigated. Hydrostatic pressure is found to raise the modulus of elasticity, the tensile strength, and the elastic limit. Approximate equations for calculating the strength and elastic properties under various amounts of hydrostatic presure are proposed.Mekhanika polimerov, Vol. 1, No. 1, pp. 65–75, 1965     

Effect of the conditions of prepreg preparation on the strength of structural plastics

A study is made of the effect of the temperature and duration of heat treatment of polymer composite prepregs on their strength. It is established that heat treatment under conditions ensuring close to maximal adhesive interaction between the components of the prepreg and subsequent shaping makes it possible to more than double the strength of the plastic (Table 1), A new approach is proposed to optimizing the conditions of formation of structural plastics.Paper to be presented at the IX International Conference on the Mechanics of Composite Materials (Riga, October, 1995).Translated from Mekhanika Kompozitnykh Materialov, Vol. 31. No. 3, pp. 411–416, May–June, 1995.     

Effect of silane coupling agents on the physicomechanical properties of glass-reinforced plastics

The chemical nature of the coupling agent is investigated in relation to its effect on the wet and dry flexural strength of specimens of polyester glass-reinforced plastic (GRP), the water absorption of the material, and the degree of polymerization of the resin.Mekhanika Polimerov, Vol. 3, No. 5, pp. 787–794, 1967     

Effect of supermolecular structures on the self-heating of plastics under cyclic loads

It was established that the intensity of self-heating of polycaprolactam specimens under the influence of cyclic loads depends on their supermolecular structure. The coarser the supermolecular structure and the larger its variation across the specimen cross section, the higher is the increase in the specimen temperature due to self-heating. Changes taking place in the supermolecular structures of polycaprolactam specimens under the influence of cyclic loads were analyzed, and it was shown that the introduction of artificial nuclei of structure formation promotes the ordering of supermolecular structures in polycaprolactam, which produces a substantial reduction in the temperature reached as a result of self-heating due to cyclic loads.Mekhanika Polimerov, Vol. 2, No. 6, pp. 803–807, 1966     

Effect of curvature of the fibers on the elastic properties of unidirectionally reinforced plastics

An approximate method is proposed for determining the reduced elastic constants of reinforced plastics (glass-reinforced plastics) with allowance for the curvature of the reinforcing fibers. All the conclusions relate to plane stress. The results of model tests are presented as confirmation of the theoretical conclusions.Mekhanika Polimerov, Vol. 3, No. 5, pp. 858–863, 1967     

Effect of temperature and anisotropy on the elastic constants of oriented glass-reinforced plastics

The experimental temperature dependence of the modulus of elasticity and Poisson's ratio are presented for SVAM oriented glass-reinforced plastic. The possibility of treating SVAM sheet as orthotropic at elevated temperatures is demonstrated.Institute of Chemical Physics, AS USSR, Moscow. Translated from Mekhanika Polimerov, Vol. 4, No. 6, pp. 1026–1032, November–December, 1968.     

Effect of surface modification on the adhesion and mechanical properties of glass-reinforced plastics

The adhesion of an epoxy-polyester resin to glass fibers with clean and modified surfaces has been determined. The effect of this adhesion on some of the properties of glass-reinforced plastics (bending, tension, shear) is investigated.Mekhanika polimerov, Vol. 1, No. 1, pp. 93–99, 1965     

Effect of loading regime on the heating of plastics subjected to cyclic deformation

In cyclic loading in the W = const and ₀ = const regimes, as in the ₀ = const regime, both a low-temperature and a high-temperature thermal regime may exist, with an abrupt transition from the former to the latter. The effect of the loading regime on the temperature dependence of the hysteresis temperature rise T, which depends on the elastohysteresis properties of the material, results in the following relationship between the critical temperature rises: T ₀ ^c T _W ^c T ^c .Scientific-Research Institute of Plastics, Moscow. Translated from Mekhanika Polimerov, No. 3, pp. 465–469, May–June, 1969.