The results are given of an investigation of the effect of explosive pressing on the structure and properties of Phenylone S3. The optimum pressure of explosive pressing and the optimum temperature of subsequent sintering of preforms of 3-10 mm thickness were determined. The thermomechanical properties and the structural changes of Phenylone were investigated after shock-wave and heat treatments. The physicomechanical properties of Phenylone S3 after explosive pressing are compared with those of Phenylone S2 produced by hot pressing. Phenylone (a trade name used in Russia for the linear aromatic [-NHC 6 H 4 NHOCC 6 H 4 CO-] n polyamide polymeta-phenylene isophthalamide) possesses a fairly high prolonged temperature service, high hardness, rigidity, and strength, and good antifriction and other properties. On account of this, Phenylone is used mainly for the manufacture of components and assemblies undergoing severe service conditions.

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A part of any complexity may be presented as a combination of smooth elements and those with design concentrators of mechanical stresses. As a consequence to a first approximation it is possible to investigate smooth samples for the assessment of material fatigue properties. An optimum formation of experiments on the assessment of fatigue strength, reliability and resource of the machine under design is a complex and significant problem. To carry out experiments for fatigue there are used testing machines of different kinds. A type of a testing machine is defined reasoning from the purpose of the work and possibilities of an experimentalist. Subject to the process of changes in time of stresses in a sample one differs fatigue tests at harmonic loading (symmetric, asymmetric cycle), biharmonic (application of two and more harmonics), program (change of stress amplitudes according to a certain program) and random at different types stochastic processes. The problem of machine reliability increase at the expense of destruction elimination in consequence of structural material fatigue is urgent in most of branches mechanical engineering. A topicality is particularly urgent in branches where accidents and breakdowns owing to the destruction of significant parts result in disastrous effects (power engineering, cosmonautics, aircraft, transport of all kinds and so on). For correct assessment of reliability and resource of significant parts subjected to time loads the test conditions approach to operation conditions. The purpose of this work is improvement of design- experimental methods for the assessment of machine reliability at the expense of test conditions approximation to operation loads.