This paper implements a Case Study Analysis method within the Mechanical engineering masters’ course Module T210M109 Microelectromechanical Systems Design at Kaunas University of Technology. This method guides students through experimental planning, fabrication, characterization, and interpretation, leading to deeper understanding of membrane composition and its structure, and relationship between properties and real-world engineering application areas. The paper examines the implementation and educational issues in design of composite nanofiltration membranes used in removal of microplastics (MPs) and nanoplastics (NPs) from water. It highlights both, the scientific challenges of membrane fabrication and the pedagogical value of integrating Case Study Analysis into engineering. Thus, students demonstrated improved ability to make technical decisions, analyze the cases of different microfabrication techniques and interpret the obtained results with the help of Case Study method.

Misalignment and unbalance are two major mechanical faults in rotating machinery. In recent years, with the increasing application of permanent magnet coupling in rotating machinery, it is necessary to study the misalignment and unbalance of rotor system with permanent magnet drive. In this paper, the vibration characteristics of centrifugal pump rotor system driven by asynchronous disc permanent magnet coupling（ADPMC）considering misalignment and unbalance faults will be discussed. First, the three-dimensional models of ADPMC with axial and radial misalignments are established respectively, and the axial and radial unbalanced magnetic pull of ADPMC are solved. Second, the axial force of angular contact ball bearing and radial force of cylindrical roller bearing are calculated under different operating conditions. Further, the radial support stiffness of each bearing is obtained. Third, the modal analysis of rotor system driven by ADPMC is carried out to obtain the natural frequencies and modal shapes. Finally, the radial unbalanced magnetic pull of ADPMC and unbalanced force caused by mass eccentricity of impeller are taken as the excitation sources, and the harmonic response of rotor system are calculated. The results show that the axial misalignment of ADPMC will cause a larger unbalanced magnetic pull, and the radial misalignment of ADPMC will lead to a smaller unbalanced magnetic pull. When ADPMC has different misalignment faults, the natural frequencies of same modal order of rotor system are basically the same. In the vicinity of the operating frequency, the vibration displacement at two journal of the rotor system excited by dual excitation sources are both small. Therefore, large radial misalignment of ADPMC can be allowed in rotor system, and ADPMC has good vibration isolation characteristics between the driver shaft and the driven shaft. The results provide important engineering references for the application of ADPMC in rotating machinery.

Safe electrical energy transport on high-voltage overhead lines requires the physical-mechanical characteristics of aluminum-steel conductors and steel cores to be experimentally determined and compared to standard values. The basic characteristics of aluminum-steel conductors can be obtained by tensile testing to failure. Such tensile tests are regulated by the standards: CEI-IEC 1089, CEI-IEC 61089, SR-CEI 1089 and BS EN 50182. Because of a wide rigidity range, aluminum-steel conductors require adapted testing conditions and experimental data analysis, ensuring that by tensile testing the most important mechanical characteristics can be put into perspective, for the whole conductor and for its core. Therefore, a complete conductor testing procedure has been developed in this paper, according to the European standards in effect and applied for two conductors with a rigidity ratio of 4.42. The experimental tests were carried out on a horizontal tensile machine, designed and built in the Laboratory for Conductors and Cables of the “Politehnica” University of Timisoara, Romania, having a length of 13 m and developing a force up to 2500 kN. The tensile tests have firstly shown that a (sometimes significant) difference can be observed between the stress-strain curves obtained according to the standards in effect and the ones based on the strains measured at the beginning of each hold period. This shows the creep tendency of conductors over a short period of time, when exposed to overloads. Secondly, it has been found that in case of high rigidity conductor steel cores, current standard testing is limited only to the elastic region.DOI: http://dx.doi.org/10.5755/j01.mech.19.4.5048

Finite element based models for cutting operation present outstanding complexities due to their nonlinear and multi-physics coupling. Nevertheless, there is no uniform standard for the comparison between cutting simulation models based on different software. The present work deals with various methodologies to simulate orthogonal cutting operation for Ti-6Al-4V Titanium alloy inside two commercial codes: ABAQUS and DEFORM. The aim is to show how considered optimal FE numerical approaches can imply agreements or disparities in outputs between the two pre-cited codes. In order to carry out a comparative study between the two codes, similar conditions concerning geometrical models and cutting parameters were adopted. A multi-physic comprehension related to chip formation, cutting forces, temperature evolutions, and surface integrity was presented. Moreover, the numerical results were compared with experimental ones for a deeper discussion on numerical predictions, and problems with current simulation were addressed to improve and support process innovations.DOI: http://dx.doi.org/10.5755/j01.mech.19.3.4656

Natural dry draft cooling towers are one of the most popular types of towers in power plants that are being used in dry climate areas. One problem with this type of tower is the impact of environmental factors on their performance. Wind is one of these factors. Wind develops a phenomenon called wind cover that prevents outgoing gasses from escaping. In this work, the effects of wind on flux and distribution of output velocity in tower outlet is studied by using wind tunnel and hot wire anemometer. Also the effects of wind break walls are studied with respect to hampering these effects.DOI: http://dx.doi.org/10.5755/j01.mech.19.3.4653

The article analyses the processes of heat circulation in the plate regularly supplying the varying flow of heat. The construction of the plate where the heat energy is transformed into mechanical work is presented. Applying the method of idealization the working principle and the principal construction of engine converting heat to mechanical work are introduced. The thermodynamic cycle of engine with the processes within are examined. With temperature change by 1 ° C the thermal efficiency coefficient of engine will be below 0.0034. The theoretical cycle of heat transference into mechanical energy does not encounter the loss of energy. This results from the assumption that after having activated the circulation processes in the border layer and performed a certain mechanical work finally the mechanical energy is reconverted to heat. DOI: http://dx.doi.org/10.5755/j01.mech.19.3.4661

In this paper experimentally analyzed mutual part alignment using elastic vibrations in automated assembly. The peg fixed in a gripper and elastic vibrations excited in longitudinal direction by mean of the pressed piezoelectric vibrator. The end tip of the peg vibrates in longitudinal and lateral directions in the contact point with the bush. It forces to move bush respectively to peg along the part alignment direction. Experimental setup and methodology explained. Influence of axis misalignment, initial pressing force and excitation frequency/amplitude to the stable and reliable alignment duration using parts from different materials with different shape/size has been determined. DOI: http://dx.doi.org/10.5755/j01.mech.19.2.4164

This paper presents the results of a study on the weaving beams across a straight elliptical cross-section by filament winding. The study determines, block by block, numerical values of the displacements of the rotating mandrel and guides of the eye in translation and in rotation, provided that the timing of these changes provides a removal of the tape with the chuck according to geodesic lines. The numerical values obtained by an incremental method applied to the rotation of the mandrel are then stored in a file. This file is generated by the program as a basis for data to then develop the program executable by the digital control in order to control the weaver. The error of the calculation recorded by filament wound is insignificant on the movement of the eye guide and does not affect the cycle. This is a demonstration of the efficiency of the application and responds to the composite winding method.DOI: http://dx.doi.org/10.5755/j01.mech.19.2.4159

The article presents the investigation of the operating cyclogram of grouping device of packages of salmon fillet. The system Solidworks Motion helped to create a calculative model using the geometric basis of grouping device. The numeric analysis revealed rational parameters of working cycle of grouping device. The maximal reaction force of the cart was determined as it rises 3.18 s from the cycle’s beginning and is equal to 56 N. This does not exceed evidently the maximal allowable load of the gear of linear motor (150 N). The methodology of investigation of work cycle of the grouping device was formed that enables to determine the rational working parameters.DOI: http://dx.doi.org/10.5755/j01.mech.19.1.3627

The calculation of cracking moment of flexural reinforced concrete elements is made in the article by evaluating the elastoplastic state of concrete. At the time of crack opening, the concrete strain modulus is calculated on the ground of the coefficient of elastoplastic strains. It is accepted in the calculations that, when stresses reach maximal values, the coefficient of concrete elastoplastic strains is the same for both tensile and compressive zone. The presented model can be used to calculate the stress and strain values of uncracked element section with regard to bending moment not exceeding cracking moment. In this case, it is taken that when stresses exceed elasticity limit the coefficient of elastoplastic strain will decrease gradually to the limit value if maximal stresses are reached. In order to simplify the solution of formed integral equations, the method of layers and the finite element method are proposed for solving. The proposed method is convenient because it can easily be used to evaluate the potential changes of concrete elastoplastic coefficients.DOI: http://dx.doi.org/10.5755/j01.mech.19.1.3619