Effect of proton-electron irradiation on the strength of a glass-reinforced plastic and its components

The action of protons and electrons on the properties of glass strands under vacuum conditions has been experimentally investigated. The experimental procedure is described. The effects of irradiation, strain rate, and reduced temperature and pressure on the properties of glass reinforcement and glass-reinforced plastics are estimated.Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev; Physicotechnical Institute of Low Temperatures, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 4, pp. 755–760, July–August, 1970.     

Elastic and strength characteristics of a glass-reinforced plastic in compression

The elastic constant and strength characteristics in compression have been experimentally determined for a cold-cured glass-reinforced plastic in the direction of all three principal axes of anisotropy. It is shown that the elastic constants obtained satisfy the constraints imposed on orthotropic materials by the thermodynamic relations.Translated from Mekhanika Polimerov, No. 5, pp. 866–869, September–October, 1970.     

Correlation analysis and strength of glass-reinforced plastic pipe

The correlation between certain input characteristics of glass cloth reinforced plastic pipe and product quality is evaluated. The almost total lack of both interfactor and multiple correlation is noted. The parameters that should be controlled in manufacturing pipe for purposes of obtaining the necessary correlation are listed.Moscow. Translated from Mekhanika Polimerov, Vol. 4, No. 6, pp. 1014–1019, November–December 1968.     

Method of estimating the strength of glass-reinforced plastic shells

A combined method of estimating the strength of glass-reinforced plastic shells in the plane stress is described. The method consists in a combination of destructive and nondestructive methods of determining the necessary starting characteristics for use with a criterion of the strength of orthotropic materials in the form of a fourth-degree polynomial.Ritm Scientific-Production Association. Central Scientific-Research Institute of Shipbuilding Technology, Leningrad. Translated from Mekhanika Polimerov, No. 3, pp. 571–573, May–June, 1972.     

Determination of the mechanical characteristics of a glass-reinforced plastic during winding

Problems associated with the determination of the transverse modulus of the material under compression during winding are examined. The rheological characteristics of the material are investigated on the basis of the short-time and long-time creep curves for winding processes conducted at normal and elevated temperatures.Ordzhonikidze Moscow Aviation Institute. Translated from Mekhanika Polimerov, No. 1, pp. 162–164, January–February, 1973.     

Anisotropy of the low-cycle tensile fatigue strength and deformability of a glass-reinforced plastic

Experimental results on the anisotropy of the strength and deformability of a 1:1 SVAM oriented glass-reinforced plastic in low-cycle tension in the directions =0, 15, 30, and 45° are discussed. The loading frequency was 1–1.5 cycles/minute. A three-dimensional fatigue strength diagram is constructed in _max - - log N coordinates. It is shown that in the direction =0° the fracture strain depends on stress, whereas at 0° the glass-reinforced plastic fails at almost the same maximum strain, the value of which depends on , but is invariant with respect to _max. It is established that the rate of development of the strain extrema on the linear part of the (N) graph and the stress _max are related by a power-law dependence, whose parameters are determined by the anisotropy of the mechanical properties of the composite.Institute of Mechanics, Academy of Sciences of the Armenian SSR, Erevan. Translated from Mekhanika Polimerov, No. 3, pp. 425–429, May–June, 1976.     

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     

Microwave determination of the mechanical strains in glass-reinforced plastic articles

The theoretical basis for the relation between the change in the electrical parameters of a glass-reinforced plastic article and the mechanical load is examined. Results of experiments confirming the dependence of on are presented.For communication 1 see [2].V. I. Ulyanov (Lenin) Leningrad Electrical Engineering Institute. Translated from Mekhanika Polimerov, No. 5, pp. 917–922, September–October, 1975.     

Plane-stress creep of a glass-reinforced plastic

The creep behavior of an orthotropic glass-reinforced plastic based on Polimal'-109 resin and 19-S4 glass fabric is described. A special device for testing tubular specimens in plane-stress creep has been designed. The loading conditions include combined torsion and tension, internal pressure, and loading along the principal directions of anisotropy. Constitutive equations describing creep and recovery are proposed for the two-dimensional case.Warsaw. Translated from Mekhanika Polimerov, No. 3, pp. 398–410, May–June, 1971.     

Effect of ultrasound on the properties of a glass-reinforced plastic

It is shown that removing paraffin size from the glass strands by means of ultrasound has little effect on their strength, improves the structure of the material, and raises the mechanical strength of the GRP by 11–12%. An ultrasonic strand cleaner employing focusing piezoelectric ceramic transducers is described.Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 3, pp. 546–548, May–June, 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.     

Statistical estimate of a static strength criterion for AG-4s two-way glass-reinforced plastic

The statistical characteristics of the static strength of AG-4s entering into the equations of the strength criteria for anisotropic materials are determined. The agreement between a series of existing criteria and the test data is estimated. A theoretical estimate of the mathematical expectation and variance of the function for the criterion best adapted to the material in question is obtained on the basis of the method of linearization of a function of several random arguments. The theoretical and experimental data are compared.Moscow Aviation Technological Institute. Translated from Mekhanika Polimerov, No. 6, pp. 1117–1120, November–December, 1973.     

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.     

Optimal reinforcement of a glass-reinforced plastic plate

Relations are derived for the optimal arrangement of the reinforcement in a rectangular glass-reinforced plastic plate supported at the edges and stressed in uniaxial compression by a short-term or long-term, uniformly distributed load. (The optimal arrangement is understood to be that which maximizes the critical load.)All-Union Scientific-Research Institute of Railroad Transport, Moscow. Translated from Mekhanika Polimerov, No. 4, pp. 741–744, July–August, 1969.     

Investigation of the extremal directions in a glass-reinforced plastic

The extremal directions in an orthotropic material are investigated on the basis of six experimentally determined values of the investigated characteristic in the three planes of symmetry of the material.Translated from Mekhanika Polimerov, No. 4, pp. 742–745, July–August, 1971.     

Effect of the low shear strength of the resin layer on the carrying capacity of glass-reinforced plastic pipe

The author considers a special type of failure—the "unwinding" of a pipe under pressure. It is shown that the cause of this is the low shear strength of the resin. Equations are obtained for determining the bursting pressure. An analysis of these equations suggests means of avoiding failures of this type.Mekhanika Polimerov, Vol. 3, No. 3, pp. 553–556, 1967