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The paper presents chosen results of surface micro-geometry examinations carried out for elements produced from NC.100.24 iron dust by the die pressing method. Dependence of parameters such as Ra, Rz i Rp on pressing pressure as well as iron dust grainless has been illustrated in a graphic form of diagrams. It was noticed that the above mentioned parameters that are universally applied for surface...
New aspect of the issues of assembly process designing have been presented in the article. It is based on the separation of the process into several stages and presenting them in the mathematical model forms which enable the transition to numerical models and computer programs being the design basis of the rational assembly processes.
This paper provides a comprehensive knowledge on the frictional bahaviour exhibited during the cutting process resulting from the influence of so-called heat isolating coatings deposited on a WC-Co carbide substrate. For this purpose orthogonal end-turning tests with medium carbon and austenitic stainless steels when using tools treated with both multilayer coatings with intermediate Al2O3 ceramic...
Requirements for flexible manufacturing have been increasing in the last years. In order to insure effective operation of expansive manufacturing equipment, which has to run automatically and unattended, tool monitoring is important. Therefore, the essential problem to be overcome to achieve the full potential of unmanned machining is the development of effective and reliably sensors systems to monitoring...
This work is focused on possibilities for an increase in the efficiency rates of steam turbine settings. It presents the structure of a new generation of control valves. It also discusses the way of making the control stages more efficient and the possible ways of power loss reduction within grids of high-pressure cylinder profiles. In this context, some methods of increasing the efficiency rate of...
The multi-disciplinary optimization (MDO) was applied to design of a compressor impeller and was completed after replacing titanium with aluminium. A two-step optimization method was used. Loop 1 combined quasi-3D aerodynamic method and blade-alone FEA models, with reduced blade stress goals while matching blade loadings. Loop 2 used a 3D pie-slice FEA model with decreased bore stress goal. The redesigned...
This paper presents an analysis of tendencies in development of aircraft engines in terms of application of new nickel and cobalt-base alloys. The criteria of selection of materials, testing methodology and examples of new nickel and titanium alloys are discussed here.
A numerical study of cavitation within a centrifugal pump was conducted using Fluent 6.1. The goal of the study was to investigate the ability of a new multiphase mixture cavitation model to predict the onset of cavitation withing the pump blading. Steady-state calculations were performed for a range of flowrates without cavitation to examine the pump performance. Comparisons of head rise with the...
A three-dimensional numerical analysis for aerodynamic unsteady forces and flutter parameters acting on the last stage steam turbine 13K215 rotor blades and total unsteady forces acting on the shaft have been presented. The low frequency excitation was simulated for a 94 rotating blades with 54 nozzles, it was assumed that the pressure behind tha rotor blades is changing in the circumferential direction...
The investigations of polymer electrolytes with non organic fillers applied in the Abrasive Flow Machining (AFM) are presented in this paper. A flow of cations and anions is discussed for half-liquid electrolyte. The influence of electrolyte flow velocity on the current density is estimated for constant inter-electrode gap value and constant voltage. The results of the anode surface roughness measurements...
This paper presents the influence of deformation conditions (temperature and strain rate) on resistance of plastic flow and critical strain of Ti-5Al-5Mo-5V-1Cr-1Fe alloy. Based on the results from sequential deformation with a torsion plastometer the relative volume of the recrystalized phase. The actual deformation temperature was measured with a pyrometric method and an infrared mapping method...
The chosen results of study when turning porous materials on the base of powder iron containing additives of graphite, copper, sulfur and chromium are presented in the paper. The values of cutting forces when turning soft materials "iron - graphite" are lower by about 10-20% in comparison with monolithic materials, and when turning hardened materials they are higher. The ratio between cutting...
In this paper theoretical analysis of electrochemical machining with a vibrating electrode has been presented. Physical phenomena which perform in the interelectrode gaps have been described by the system of partial differential equations resulting from mass, momentum and energy conservations of electrolyte in the gaps. Formulated in this paper equations describing evolution of shape of anode workpiece...
The paper presents results of the practical veryfication of the algorithm of shaping dynamic properties of machine tools aimed at improvement of vibrostability. Analytical and experimental investigations proved the effectiveness of the proposed algorithm.
The paper presents an original method of modelling of complex system, which joints advantages of experimental and fuzzy logic methods. Such models contain precision knowledge obtained by experimentl methods, as well as "expert knowledge" which is often approximate and incomplete. The main stage of proposed method - conversion from regresion to fuzzy model is described. The method was applied...
Components of the cylindrical traverse grinding force are the key values, which significantly influence each process of grinding. Based on the theoretical analysis and experimental testing, this paper prestents a model of components of the grinding force in the process of cylindrical traverse grinding - the normal grinding force Fn and the tangential grinding force Ft. The presented model can be used...
In the paper some results of numerical analysis of durability glue joints under long-lasting loading are presented. In the numerical investigation software environment Nastran for Windows was made use of. In the numerical investigation viscosity-elastic properties were modelled by Burgers' body. The properties of component elements of Burgers' body were determined on the basis of glue creep curves...
The plasticizing system of the extruder, where inter-thread clearance plays an important role, is made up by two worms. A description of the surfaces of cone worms machined with a conical end mill and the method of determining clearance at the stage of the design of the construction and technology of worms have been given.
This paper's attempt is made to analyse the current status of the research with focus on the techniques used to modify the surface of titanium alloys by laser nitriding, the most often used method to improve the properties, which is caused by that nitrogen can be easily introduced into the molten material. Laser nitriding technique, microstructure and phase composition of the surface layers, surface...
The paper presents the model of an adhesive joint designed according to the finite element method convention. The presented model takes into account the existence of hypothetical defects in the boundary layer of the adherend and the adhesive. The article contains a description of the strength tests as well as all the procedure of conforming the computed models to the results of experimental research.
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