A procedure is presented to predict fatigue failure of thick-walled cylinders containing discontinuities at the OD. Both crack initiation life and crack growth are considered. The elastic-plastic strains at an OD discontinuity are estimated using an elastic analysis and stress concentration factors. The strain estimates are then used in conjunction with low cycle fatigue data to determine the initiation life. Crack growth life is estimated by integration of a power law relationship. The results obtained by using this analysis method compared to measured fatigue life data for several OD initiated failures in thick-walled cylinders agrees to within about 10 percent.

Close tolerance metallic sleeves may be used as seals for reciprocating pumps or intensifiers operating at pressures up to 700 MPa. Seals of this type may be designed to provide a low friction sealing action which minimizes the usual wear problems. This paper presents the high pressure performance characteristics of such seals and examines the influence of parameters such as seal geometry, initial clearance, working pressure and fluid viscosity and temperature on leakage rates. Experimental results are compared with theoretical data generated using a computer model.

In the deep sea, truely hydrostatic pressure is produced in a very large area. This pressure may be used as natural resources. By utilizing these resources, very high pressures can be generated using a 6–8 type split-sphere high pressure apparatus. A preliminary experiment to generate very high pressure was undertaken in the deep sea at a depth of about 1000 m. Pressures of about 8.5 GPa were generated in the central part of the high pressure apparatus.

The paper presents the results of studies on the application of semiconductor p-n junctions as two-parameter transducers of high-hydrostatic pressure and of temperature in the area of the pressure. A block diagram of an electronic circuit intended to collaborate with a two-parameter transducer has been given.

Elastic distortion of the piston and cylinder is the leading cause of inaccuracy in piston gages at higher pressures. The distortion depends upon the pressure profile between the piston and the cylinder. One possible method of determining the pressure profile is demonstrated.

The calculation of the pressure generated by a controlled clearance piston gauge depends upon the jacket pressure corresponding to zero clearance between the piston and cylinder, Pz;. The dependence of Pz; on the viscosity of the pressure transmitting fluid, the temperature, and the rate of piston rotation has been measured.

The value of Pz; is nearly independent of viscosity below 60 cp. Above 60 cp, Pz; depends strongly upon viscosity. Variations of Pz; with femperature and rate of rotation are more severe at figher viscosities.

These results are a clear indication that for the most accurate pressure measurements, a controlled-clearance piston gauge must be characterized using the same operational and environmental conditions with the same fluid as in normal operation.

A method is presented of designing optimum proportions for cylinders in the composite design of a pressure vessel that limits catastrophic fatigue failure.

The finite element method has been used to investigate the stress fields in blind end closures of thick-walled pressure vessels. A design curve for choosing end thickness has been developed by elastic analysis of a range of geometries and by elastic-plastic analysis of several geometries. The effects of inner corner radius of the blind end and a small central hole in the end are discussed.

The rate of growth of fatigue cracks originating at the bore and at the outside surface of thick-walled low alloy steel cylinders has been measured for cylinders subjected to fluctuating internal pressure.

Analysis of the results using linear elastic fracture mechanics relationships shows that crack growth rates found in air adequately predict the behaviour of cracks growing from the outside surface of a cylinder.

Fatigue cracks growing from the bore of a cylinder subjected to fluctuating internal pressure are found to advance at a consistently higher rate than that predicted from crack growth rate tests carried out in air.

These findings are discussed in relation to the proposed adoption of existent strain-life fatigue data for pressure vessel design.

A method is shown to monitor the depth of plastic yielding, the permanent expansion of the cylinder and the amount of residual strain during hydraulic autofrettage. The significance of the residual stress is shown graphically.

The hydrostatic pressure in a sample, making it possible the emitting of edge dislocations by the cleavage crack, is estimated (few tens of kbars). The increase of temperature and small plastic deformation further the healing of cleavage cracks by the decay into dislocations.

The effect of the pressure 550MPa on the choice of the acting slip plane in the single crystals of Fe−2,9%Si was studied. It was established that the presence of pressure resulted in the increase of the slip asymmetry. The effect of pressure is attributed to the action of normal stresses and to the special structure of screw dislocations.

The growing interest in the process of hydrostatic extrusion is reflected by numerous publications on experimental results, fundamental researches and theoretical studies (e. g., [1] to [20]). In recent years it was the increasing demand for new materials and semiproducts with special cross-section dimensions and properties that substantiated the necessity of defining the application of hydrostatic extrusion in the field of non-ferrous metallurgy. Thus, it is the aim of the researches carried out with the experimental hydrostatic extrusion press type QEH 12 recently installed by the Swedish company ASEA in the Forschungsinstitut für NE-Metalle Freiberg of the VEB Mansfeld Kombinat “Wilhelm Pieck” to solve problems of materials and deformation engineering and to develop new technologies of producing special semiproducts from non-ferrous metals.

The process of conventional hydrostatic extrusion limits the length of the billet that can be extruded to a length somewhat shorter than that of the chamber. Production units are also limited to pressures of about 8,000 Kg/cm2. Thus the reduction that can be affected in one pass of hydrostatic extrusion of mildly tough materials like low carbon steels or copper is limited to no more than 75% R.A., if the extrusion is performed at room temperature. For subsequent passes, each previous extrudate must be cut to suitable length so it will fit again into the chamber.

The Condie process (Austen, U.S. Pat. #3,999,415) provides the means to perform extrusion through several dies, one die at a time, in one loading of the chamber. In the present model, only two dies are loaded into the chamber together with the billet. A short length is first extruded through the first die, while the second die is kept free to move idly with the extrudate. Then extrusion through the first die ceases and the billet is forced to extrude through the second die. As the second die approaches the first die and the intermediate diameter section shortens, the extrusion stops. Thus, one cycle of a finite length is completed. But, the accumulated reduction from billet to extrudate is large, similar to the reduction obtainable by a single die from a chamber of twice as high a pressure.

New method for identification of the kind of elastic stress-free crystal imperfections which are not visible by standard X-ray and electron microscopy methods was presented. The method is based on the high pressure annealing creating large stresses at defect sites,followed by X-ray topography. This method was applied in structural defects studies of high quality silicon single crystals and allowed to determine the composition and structure of precipitates in silicon.

The criterion for complete fracture of the casing by detonation of packed high explosive was first presented by G.I.Taylor. Thereafter Taylor criterion has been reviewed and extended by many authors. This paper is intended to present a clear understanding of the fragmentation mechanism, and to study the influence of stress waves on the fracture of the casing using finite difference calculation of elastic-plastic flow. The results show that Taylor criterion is correct to a certain extent.