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In this paper the structure and the ability to protect the castings made from GX25NiCrSi36-17 cast steel against carburization with the use of the coatings produced directly in a casting mould have been described. To analyse the structure the following methods of testing were used: an optical and electron microscopy, X-ray microanalysis, X-ray diffraction and quantative image analysis. It can be stated...
Paper presents the algorithm of complex vibrostability analysis of machine tools in end milling. Particular stages of vibrostability forecasting using stationary and nonstationary MT-CP system models are discussed. Algorithm deals also with the problem of model reduction for the need of vibrostability analysis and methodology of detection of weak points with respect to vibrostability. An example of...
The paper presents a modification of method of approximation of frequency characteristics. Practical application showed its weak points. The method of determining the initial value has been modified. The module for determining the optimum number of independent variables of linear equations system, solved iteratively by the last squares method, has been worked out, as well as the module for eliminating...
This paper proposes a computer aided control system, which manages both efficiency and flexibility in the manufacturing system. It has been considered that application of Fuzzy-Logic methods is necessary for the multicriterial control of production systems. The proces of production scheduling involves applies an algorithm of lingustic rules generation on the basis of numerical data. The quality of...
The paper contains the method of failure detection on the basis of incomplete measurements, which means that the number of measured signals is lower than the number of degrees of freedom of mechanical systems. The method does not require reducing the number of degrees of freedom of mathematical model and therefore identified parameters can be physically interpreted. The proposed indicator is based...
Generalisation and sistematization of results of our own investigations, focused on elaboration and creation of wear resistant materials and coatings based on steels, carried out for the last 15 consequent years, testify the promising future of heterogeneously structural materials. Some variants of obtaining of such materials, and peculiarities, like: (a) thermomechanical treatment of steels with...
This paper presents the method of determination of the global sensitivity index of the vibrostability limit to the charge of mass-damping-spring parameters of machine tools models. The non-stationary character of the models is handled by the analysis of operational variants. The global sensitivity indexes are calculated on the basis of frequency of variant appearance and for vibrostability limit that...
Defects in composite structures initially depend on the lay-up of the material and occur in manufacturing as well as through local loads in service. They can expand and develop into damages which will affect safety. Normally, nondestructive test methods are used for detecting and evaluating the defects, but vibration test methods are also suitable. The sensivity of vibration parameters, such as frequency...
The paper presents the reduction procedure of number the degrees of freedom of mechanical systems models built of finite elements. The procedure is especially useful for reducing the number of degrees of freedom of models built of rigid finite elements. Its significant feature is preserving influences of the coordinates rejected from the model on the active coordinates in the reduced model by means...
The paper presents methods of solution and points out problems that are encountered when determining static stiffness and friction in rolling guides of machine elements. It is shown how model calculations could help in measurement preparation and interpretation of experimentally obtained results. Difficulties concerning the meaurements of friction forces in the connection are duscussed. Static stiffness...
Thermal-cathalitic decomposition of methane in process of production of fertilizers is executed in the reformer tubes made from austenitic cast steel 24/24 Nb. The process is carried out in the atmosphere of water vapor at the temperature 850 degrees C under pressure 3,2 MPa. The mechanical properties and phase composition of these tubes were changing during a long service. On the basis of the carried...
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