Most studies on solenoid valves (SVs) assumed that the armature is concentrically positioned in the sleeve. Under this assumption the transversal component of the magnetic force is equal zero. The article presents an analytical calculation model for the estimation of the armature eccentricity. Using this model the eccentricity was calculated as a function of the sleeve thickness and the hydraulic clearance between the armature and the sleeve. After finding the eccentricity also the permeance of the radial air gap was calculated. This permeance has a direct influence on the drop of the magnetomotive force in the magnetic circuit and finally influences also the axial component of the magnetic force. In the article a calculation of both transversal and axial components of the magnetic force was carried out and presented in the appendix to the article.

The article explores the possibility of using the authors’ three new methods of unconventional extrusion of deep hollows to be used for the manufacture of spline sleeves intended for internal toothing couplings. Two invention patents, PL206466 and PL224121, and one patent application, P.416772, were used for this purpose. Numerical computations were made in the Forge®3D program for the conceptual schemes of forming sleeves. The aim of those computations was to determine the extrusion forces and to compare them with the conventional indirect and direct extrusion methods. Then, on models based on the authors’ plastic forming schemes, numerical computations were made, from which the actual energy and force parameters were determined in the form of the relationship of extrusion force versus forming tool path. Also, the degree of fill of the passes, in which spline sleeve toothing is formed, was determined.

In the paper presents two new patented of unconventional methods author’s and sleeve-type products of extruding [PL219182, PL221425]. The extrusion methods have been developed with the aim of reducing the energy and force parameters during the plastic forming of material. Traditional methods of extruding similar products are characterized by considerably higher extrusion force magnitudes. This results in substantial limitations and problems of an engineering nature. Moreover, the proposed methods of producing bottomed and bottomless sleeves are distinguished by the capability to minimize or totally eliminate the waste. The author’s methods of extruding long bottomless sleeves, presented herein, were used for developing a method for shaping inner toothing in spline sleeves. The theoretical analysis is based on thermomechanical simulation of the possibility of applying such processes to the extrusion of spline shafts with inner toothing. Next, the obtained results were compared with analogous parameters for classical indirect extrusion. The possibility of shaping inner toothing over the entire product length according to the proposed spline sleeve plastic forming methods was also explored.

The aim of this paper is twofold: to estimate the unsteady pressure-flow variations in gas transmission pipelines using the ensemblebased data assimilation approach and to analyse the strength of steel tubes reinforced with composite sleeves containing localized part-wall thickness loss caused by corrosion while taking into consideration a safe operating pressure of the pipeline. For a steel thin-walled cylinder containing a partwall metal loss, a flexible wrap of fibreglass as well as carbon glass with epoxy resin are determined. The strength of the repaired pipeline with two kinds of materials for sleeves is investigated taking into consideration the internal pressure at the defect location. For the case study, a section of the Yamal transit pipeline on the Polish territory is selected. The results enable pipeline operators to evaluate the strength of corroded steel pipelines and develop optimal repair activities, which are of vital importance for the maintenance and operation of underground steel networks.