Mechanical properties of glass fabric-reinforced plastics in tension and compression normal to the plane of reinforcement

The behavior of glass-reinforced plastic based on ASTT (b)S₂-O fabric and NPS-609-21M resin in tension and compression normal to the plane of reinforcement has been investigated and the mechanical characteristics determined. Recommended values are given for the size and shape of the test pieces, and a method of determining the tensile and compressive characteristics of glass-reinforced plastics is proposed.Leningrad. Translated from Mekhanika Polimerov, Vol. 4, No. 5, pp. 803–809, September–October, 1968.     

Estimation of the stability of the strength of glass-reinforced plastics in conical shells

On the basis of a statistical analysis of the test data it is shown that there is a difference between the mechanical characteristics (in tension and compression) of laminated glass-reinforced plastics obtained under laboratory and industrial conditions by impregnation under pressure in a closed mold. The stability of the strength properties of the glass-reinforced plastic in various conical shells, produced in large batches, is considered. Certain experimental relations between the material properties and the total number of shells produced are also established.Moscow. Translated from Mekhanika Polimerov, No. 1, pp. 102–108, January–February, 1970.     

Mechanical characteristics of radiation-cured glass-reinforced plastics

Data are presented on the mechanical characteristics of oligoester maleates copolymerized with styrene and the corresponding glass-reinforced plastics crosslinked by the thermochemical and radiation methods. It is established that the radiation-cured glass-reinforced plastics have improved strength and stiffness as compared with similar specimens obtained by thermochemical curing.Institute of Mechanics, Institute of High Molecular Compounds, Institute of Physical Chemistry, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 4, pp. 704–710, July–August, 1969.     

Glass-reinforced plastics based on matrices combining thermoplastics and thermosetting plastics

The conditions of fabrication and the physicomechanical properties of glass-reinforced plastics based on polysulfone combined in different ratios with epoxy resin and Rolivsan were investigated. It was found that realization of the strength of the fibers in glass-reinforced plastics based on three types of binders and mixtures of them at room temperature is approximately the same. The lower strength of glass-reinforced plastics based on polysulfone is determined by the lower concentration of fibers. Modification of thermosetting plastics with polysulfone significantly increases (by 5–8 times) the specific energy of delamination of the glass-reinforced plastics G_1c, which should be manifested by an increase in their crack resistance and other operating characteristics. Modification of ED-20 with polysulfone and polysulfone with Rolivsan significantly increases the glass transition temperature of the polymer and affects the character of the temperature curves of the strength of the glass-reinforced plastics.Institute of Chemical Physics, Russian Academy of Sciences, Moscow. D. I. Mendeleev Russian Chemical Technological University, Moscow. Translated from Mekhanika Kompozitnykh Materialov, No. 1, pp. 111–117, January–February, 1996.     

Statistical characteristics of the mechanical constants of glass-reinforced plastics

The results of statistical treatment of experimental data on the physicomechanical properties of glass-reinforced plastics, based on alkali-free, aluminoborosilicate glass fibers (composition NS-55/6) with paraffin as lubricant and epoxyphenolbutyral composition EFB-4, obtained from tensile tests on flat specimens prepared by "wet" winding on a mandrel, are given. The data can be used for evaluating the effect of the scatter of the mechanical constants of a composite material on the efficiency of a structure and its elements.Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 6, pp. 1125–1128, November–December, 1972.     

Mechanical behavior of cylindrical laminated plastic shells

The static and dynamic behavior of a cylindrical glass-reinforced plastic shell with an open cross section under long-term loading and unloading has been experimentally and theoretically investigated. The experimental results are compared with the theoretical data obtained using a geometrically nonlinear theory based on the Kirchhoff hypothesis. For calculation purposes the glass-reinforced plastic is assumed to be a homogeneous orthotropic linearly elastic material.Building Research Institute, Prague. Translated from Mekhanika Polimerov, No. 1, pp. 110–115, January–February, 1976.     

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.     

Mechanical properties of a hollow-fiber glass-reinforced plastic

The strength and elastic properties of a hollow-fiber glass-reinforced plastic are investigated together with the effect of temperature, and long-time and cyclic loading on its mechanical characteristics. The instantaneous moduli of elasticity and the creep kernel parameters are obtained on the basis of the creep diagrams.Translated from Mekhanika Polimerov, No. 2, pp. 341–345, March–April, 1971.     

A rheological model of polymers and glass-reinforced plastics

Network polymers and the corresponding glass-reinforced plastics are investigated for a homogeneous uniaxial state of stress and constant temperature. A physical law relating the high-elastic strain and the stress in explicit form with once-determined structural constants is obtained for the damped (bounded) creep regime. The theoretical solutions are compared with the experimental data for a glass-reinforced plastic based on unsaturated polyester resin and glass mat reinforcement.Institute of Engineering Mechanics, Bulgarian Academy of Sciences, Sofia. Translated from Mekhanika Polimerov, No. 5, pp. 851–857, September–October, 1971.     

Some mechanical properties of film-reinforced plastics

Model cylindrical shells have been wound from glass and Dacron (Mylar) film strip in accordance with a technique developed by the authors. A layer of glass-reinforced plastic, oriented in the direction of the circumferential tensile stresses, was applied to the outer cylindrical surface of the shells. Certain mechanical properties of the film plastics and their ability to cooperate with the glass-reinforced plastic outer layer were investigated by subjecting the shells to internal liquid pressure. The possibility of obtaining impermeable shells, equally strong in the axial and circumferential directions, was confirmed.Bauman Moscow Higher Technical College. Translated from Mekhanika Polimerov, No. 1, pp. 135–139, January–February, 1971.     

Time-temperature superposition applied to the relaxation properties of a glass-reinforced plastic and its matrix

The relaxation behavior in compression of an unsaturated polyester resin and the corresponding glass-reinforced plastic has been investigated. The time-temperature superposition principle is shown to be applicable to the cross-linked polyester resin and the glass-reinforced plastic. The temperature dependences of the shift functionsa _T of the resin and the glass-reinforced plastic are found to satisfy an Arrhenius equation with the constant equal to 21–25 kcal/mole.Scientific-Research Institute of Plastics, Moscow. Translated from Mekhanika Polimerov, No. 2, pp. 360–363, March–April, 1972.     

Mechanical characteristics of oriented glass-reinforced plastics in shear

The mechanical characteristics of oriented glass-reinforced plastics stressed in shear are considered. Various methods of determining them are compared. The dispersion of the shear strength is characterized and the possibility of glass-reinforced plastics elements failing as a result of low interlaminar shear strength is discussed.Moscow Aviation Technological Institute. Translated from Mekhanika Polimerov, No. 6, pp. 1008–1013, November–December, 1969.     

Fundamentals of the theory of non-fabric glass-reinforced plastics

Starting from the known mechanical properties of the components (glass reinforcement and resin) the stress-strain relations for an anisotropic viscoelastic material (glass-reinforced plastic) are determined. Using Volterra's principle [2] of replacing the elastic constants in the solution of the problem of the theory of elasticity [5] by integral operators, relations for the given material are obtained and found to be in fairly good agreement with the experimental data. In a separate study the high-temperature behavior of GRP is investigated by calculating the integral operators, which are functions of the viscous properties of the resin and the temperature.Mekhanika polimerov, Vol. 1, No. 1, pp. 151–158, 1965     

Behavior of composite cylindrical shells subjected to nonuniform heating

Nonlinear differential equations describing the thermoelastic behavior of closed orthotropic circular shells under nonuniform heating conditions are obtained; the temperature dependence of the elastic parameters of the material is taken into account. The problem of the stability of a glass-reinforced plastic shell hinged to fixed supports and heated nonuniformly over the thickness is solved. The results of tests on 27–63SV glass-reinforced plastic shells heated and subjected to additional compressive loads at various levels are presented. The theoretical and experimental data are compared.Zukovskii Air Force Engineering Academy. Translated from Mekhanika Polimerov, No. 2, pp. 284–292, March–April, 1971.     

Thermoelastic stresses in a nonuniform orthotropic cylinder

The stress distribution in a cylinder with cooling nonuniform with respect to the circumferential coordinate is investigated. The nonuniformity of the mechanical properties of the material in this direction is taken into account. Numerical results obtained at values of the parameters characteristic of wound glass-reinforced products are discussed.Moscow Power Engineering Institute. Translated from Mekhanika Polimerov, No. 3, pp. 560–563, May–June, 1975.     

Deformation of viscoelastic thick-walled shells in the post-critical stage

The progressive buckling of a viscoelastic cyclindrical shell with initial imperfections in axial compression is investigated in the geometrically nonlinear formulation. As distinct from previous research, shell deformation curves in the post-critical stage (after snap-through) are obtained for various load levels. The results obtained are in agreement with the experimental data. The experiments show that in the case of thick glass-reinforced plastic shells in the post-critical stage of deformation the material fails by debonding.Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No. 1, pp. 96–99, January–February, 1976.     

Static and dynamic properties of glass-reinforced plastics

The effect of the number of reinforcing layers in glass-reinforced plastics on the static and dynamic E-and G-moduli is analyzed. The experimentally obtained data are compared with theoretical calculations.Mekhanika Polimerov, Vol. 1, No. 3, pp. 87–92, 1965     

Dependence of the dynamic strength of a glass-reinforced plastic on the mechanical and geometric parameters of its components

The dependence of the dynamic strength of a glass-reinforced plastic on the mechanical and geometric parameters of its components is investigated.Moscow Institute of Electronic Machine-Building; All-Union Institute of Glass-Reinforced Plastics and Glass Fiber, Moscow Oblast'. Translated from Mekhanika Polimerov, No. 2, pp. 366–370, March–April, 1974.     

Three-dimensionally reinforced woven materials

The article presents experimental data on the deformation and strength characteristics of a number of materials reinforced with three-dimensionally woven multilayer glass fabric, which are compared with the corresponding data for traditional glass-reinforced plastics. The accuracy of the formulas proposed [1] is evaluated. The effect of prestressing the warp and weft fibers on the mechanical properties of the material was investigated. The effectiveness of simultaneous prestressing of the warp and weft was evaluated; the magnitude of the optimal force was established.See [1] for report 1.Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No. 3, pp. 471–476, May–June, 1970.     

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