Bending of a cantilevered glass-reinforced plastic cylindrical shell weakened by a circular opening

The stress concentration is investigated in the neighborhood of a circular opening in a cantilevered glass-reinforced plastic cylindrical shell with a concentrated load at the free end. The problem is solved by the Bubnov method using a Ural-2 computer. The theoretical results have been checked experimentally on glass-reinforced plastic shells.All-Union Correspondence Polytechnic Institute, Moscow. Translated from Mekhanika Polimerov, No. 1, pp. 152–157, January–February, 1970.     

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.     

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.     

Experimental methods of investigating the state of stress of glass-reinforced plastic shells

A method of testing glass-reinforced plastic shells under external hydrostatic pressure is described together with a procedure for determining the elastic properties of the material of which the shell is composed. Test data on the strength and stability of shells subjected to external hydrostatic pressure are presented.Leningrad. Translated from Mekhanika Polimerov, Vol. 5, No. 1, pp. 157–163, January–February, 1969.     

Effect of prestress on the strength of metal shells reinforced with a glass-reinforced plastic

The effect of prestress on the strength of metal glass-reinforced plastic shells has been investigated. A method of calculation is described, and experimental results showing the role of the tensile stress in the reinforcement of reinforced metal shells are presented.Mekhanika Polimerov, Vol. 2, No. 2, pp. 285–289, 1966     

Analysis of glass-reinforced plastic bottoms of cylindrical pressure vessels

Solutions are proposed for boundary value problems associated with spherical, ellipsoidal and optimal-design glass-reinforced plastic bottoms filament-wound as an integral part of cylindrical shells.Moscow Region. Translated from Mekhanika Polimerov, Vol. 4, No. 5, pp. 918–926, September–October, 1968.     

Dynamic stability of axisymmetrically heated glass-reinforced plastic cylindrical shells bonded to elastic cylinders

The dynamic stability of glass-reinforced plastic shells subjected to the action of a longitudinal pulsating force and an external, uniformly distributed load is examined. The shells are orthotropic, and their elastic properties are temperature-dependent and vary over the thickness of the wall. It is assumed that the elastic cylinder forms a Winkler foundation. Three boundary conditions are investigated.Moscow Institute of Chemical-Machine Building. Translated from Mekhanika Polimerov, No. 2, pp. 331–337, March–April, 1972.     

Stability of axially compressed cylindrical composite shells in the presence of nonstationary heating

The problem of smooth cylindrical composite shells uniformly compressed in the axial direction and subjected to nonstationary heating is solved in the linear quasi-static formulation. Expressions are obtained for the critical loads and their regions of application are determined. The calculations are compared with experimental data obtained by linearly heating the outer surface of axially compressed smooth cylindrical shells of glass-reinforced plastic based on phenol-formaldehyde resin.Zhukovskii Central Aerohydrodynamic Institute, Moscow Region. Translated from Mekhanika Polimerov, No. 2, pp. 289–297, March–April, 1973.     

Critical compressive stresses in cylindrical shells composed of orthotropic layers with different orientations

The laws of variation of the strains and critical stresses for smooth thin circular cylindrical glass-reinforced plastic shells based on ÉDT-10P resin have been experimentally investigated at different orientations of the fabric reinforcement. The results of the tests are compared with the theoretical data obtained from the relations of the theory of elasticity of an orthotropic body and orthotropic shells.N. E. Zhukovskii Central Aerohydrodynamic Institute of Production Technology and Organization, Moscow. Translated from Mekhanika Polimerov, No. 4, pp. 684–690, July–August, 1973.     

Analysis of the transition zone in combined metal/reinforced-plastic shells

The bending stresses in the conical joint zone of cylindrical shells composed of two different materials are determined for the case of internal pressure. The effect of the length of the joint on these stresses is investigated using parameters typical of steel and glass-reinforced plastic.Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No. 3, pp. 465–475, May–June, 1971.     

Dynamic stability of glass-reinforced plastic shells

The problem of the dynamic stability of circular-cylindrical glass-reinforced plastic shells subjected to external transverse pressure is examined in the nonlinear formulation. After the Lagrange equations have been constructed, the problem reduces to the integration of a system of ordinary differential equations with aperiodic coefficients. The integration has been carried out numerically on a computer for various loading rates and shell parameters. Analogous problems for isotropic metal shells were examined in [1–4]. A review of the subject may be found in [5].Mekhanika Polimerov, Vol. 4, No. 1, pp. 109–115, 1968     

Effect of the two-way reinforcing system on the load-carrying capacity of glass-reinforced plastic shells

The load-carrying capacity of thin cylindrical glass-reinforced plastic shells loaded by axial compression and external pressure has been investigated in relation to the characteristics of the two-way reinforcing system. The critical loads are expressed in terms of the characteristics of a parallel-reinforced layer with a coefficient that takes into account the reinforcing system and the shape of the cross section. The relations among the reinforcing layers optimal for the load-carrying capacity are determined and it is shown that independent two-way reinforcing substantially improves the load-carrying capacity of solid shells and shells with a nonload-bearing core.Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 6, pp. 1052–1058, November–December, 1969.     

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.     

Effect of material properties on the stability of transversely isotropic shells with an elastic filler subjected to the action of mechanical loads and temperature

The effect of the low shear strength of the material (glass-reinforced plastic) on the stability of cylindrical shells with an elastic filler is investigated in relation to axial compression, external pressure, and heating. The equations of the thermoelastic problem of the theory of monotropic shells, constructed with allowance for the effect of tangential shearing stresses, are used in the calculations.Physicomechanical Institute, Academy of Sciences of the Ukrainian SSR, L'vov. L'vov Polytechnic Institute. Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No. 5, pp. 903–907, September–October, 1970.     

Investigation of the anisotropy of the properties of glass-reinforced plastic shells

The load-carrying capacity and deformation of cylindrical and conical glass-reinforced plastic (ÉDT-10 resin) shells loaded in axial compression have been investigated experimentally in relation to the orientation of the fabric reinforcement. The results of the tests are compared with the relations of the theory of elasticity of an orthotropic body.Zhukovskii Central Aerohydrodynamics Institute, Moscow Region; Scientific Research Institute of Production Technology and Organization, Moscow. Translated from Mekhanika Polimerov, No. 5, pp. 814–818, September–October, 1969.     

Statistical characteristics of the mechanical properties of glass-reinforced plastics

A statistical analysis has been made of experimental data on the mechanical properties of a glass-reinforced plastic based on T₁ glass fabric (Soviet standard GOST 8481-61) and IF-ÉD-6 epoxy resin (Elektroizolit Plant, tech. spec. TU 26-59) obtained by testing specimens cut from the waste of wound cylindrical shells. The data obtained can be used for estimating the mechanical reliability of products composed of glass-reinforced plastics of this type.Moscow. Translated from Mekhanika Polimerov, No. 1, pp. 131–134, January–February, 1971.     

Stability of cylindrical glass-reinforced plastic shells

The stability of cylindrical shells in axial compression has been experimentally investigated. The glass-reinforced plastic shells were fabricated in various ways: by winding glass strand, from glass cloth, and by a combination of the first two methods. The buckling mode and critical load were determined as functions of the ratio of shell radius to shell thickness. A statistical analysis of the test data leads to a formula with an empirical coefficient for use in practical stability calculations.Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 5, pp. 886–891, September–October, 1969.     

Investigation of the initial imperfections and buckling modes of glass-reinforced plastic shells under hydrostatic pressure

The results of testing the stability of glass-reinforced plastic cylindrical shells under hydrostatic pressure are examined. The initial imperfections and deflections of the shells were directly measured. It is found that during loading or in the course of time (under load) the shape of the initial imperfections is transformed. An algorithm (see [11]) based on the approximation of the experimental deflection function by a Fourier series is used to establish the characteristic coefficients of the series important in connection with the elastic loss of stability and progressive buckling of the shell.Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No. 6, pp. 1057–1063, November–December, 1971.     

Stability of transversally isotropic shells coupled with an elastic foundation

The stability of shells coupled with an elastic Winkler foundation is investigated. It is assumed that the shell is made of a material (glass-reinforced plastic) with low resistance to shear, as a result of which generalized theories that take transverse shear strains into account [1–4] must be used in the stability calculations. The solution obtained is compared with the corresponding solution obtained on the basis of the classical Kirchhoff-Love theory [8].Lvov Polytechnic Institute. Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No. 4, pp. 669–673, July–August, 1969.     

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.