Abstract: The paper presents the theoretical and experimental results from evaluating the early phase of material fatigue and discusses the issues concerning the example of two object classes: supporting structures and shaft working under real environmental conditions. In theoretical considerations, the Hall-Petch and Bailey-Hirsch relationships between microstructure and mechanical parameters are given. Magneto-mechanical effects and the magnetic passive observer have been used for evaluating the early phase of material fatigue. The Metal Magnetic Memory method of structural health assessment was verified and the potential for a reliable diagnosis of damage to the ferromagnetic material at the 1st and 2nd stage was confirmed.
Abstract: In the paper, the research on the influence of drive fixing place on dynamic properties of the precision mechatronical line scales gage calibration comparator is analyzed. With the aim to research the influence of the drive on the mechanical system of the length measurement comparator, the drive mounting position was replaced, and the friction drive was changed for the rope drive.
Abstract: The aim of the research was to determine the mechanical stability of angle measurement comparator’s system. For that purpose, vibrations were measured at the significant points of the system and dynamic characteristics of the system were established.
Abstract: Recent years have faced a very modern trend for space exploration activities – constructing, launching and operating nanosatellites have become very popular. One of the major problems of implementing and taking control over the nanosatellite is ensuring accurate but simple and small dimension equipment for attitude control. Most of the equipment implemented for the introduced task was large and bulky in the past and could be hardly used on extremely small satellites. The paper describes equipment under development for attitude control over satellites. Equipment relies on the implementation of piezoelectric transducers for the rotation of a spherical body, i.e. reaction sphere, thus ensuring precise three-axis attitude control over the satellite by means of a single device. Further, the article focuses on the device under development with some calculations and examples of implementing such instruments.
Abstract: The paper compares the modification methods of polymers GUR 1050 and GUR 1020 by means of plastic deformation before (ON) and after (NO) irradiation with an electron beam (N). Evaluation of the effectiveness of the modification methods applied was carried out by means of micromechanical examinations and tribological tests on T-01 and T-05 testers (polymer/Vitalium alloy). The results of micromechanical, sclerometric and tribological tests indicate unequivocally the effectiveness of the modifications applied, as compared to the polymer modification through irradiation with an electron beam only. A decrease in hardness and elasticity modulus was found for materials subjected to the ON and NO technology as compared to N, while maintaining the growing trend of these values along with the applied radiation dose. There was also noted a large increase of the wear resistance coefficient, Wβ, and an increase of the microploughing component’s share in the wear mechanism β, which had a direct influence on the reduction of the linear wear by 2.5–3 times and a nearly twofold decrease of the mass wear. The surface subjected to friction processes became smoother and free of lamella fragments which were visible for the base material not subjected to any modifications. This was documented with the observations performed on a scanning microscope and in the stereometric examination of the surface.
Abstract: Materials used for the construction of ballistic shields are characterized by a variety of behaviours under the influence of external loads. Ballistic impact (by a bullet) in armour (ballistic shield) is an example of the phenomena that could be considered in the category of a dynamic load caused by the strike of the mass. Computer simulations are commonly used in such situations. It is especially important to adopt a proper model of the behaviour of the material. This paper presents the results obtained by simulating free 3D points and using the application developed by the authors for the purpose of this research. The made calculations include the translational motion and rotary motion of the projectile as well as the stiffness of the material, the damping of the material, friction at the points of contacting surfaces, viscous friction and plastic deformation (the material beyond the plastic yield point is perfectly plastic). The results of simulations were validated with experimental research.
Abstract: Due to instrumentation and time constraints, it is infeasible to perform thorough research, especially experiments, for all the possible solutions, encompassing a full combination of materials with the expected mechanical and functional properties and the manufacturing technologies ensuring such properties. An objectivised selection of a material for research and its surface treatment technology is, therefore, essential in the planning phase of a materials science experiment. A methodology of computer-integrated prediction of development is dedicated to such task, enabling to perform an expert assessment and to present results thereof graphically using contextual matrices being a tool of a quantitative analysis that is very desirable in engineering circles. Considering the three groups of materials, i.e.: steels, casting magnesium alloys and casting aluminum alloys subjected to an expert assessment using a dendrological matrix being an inherent part of materials surface engineering development prediction methods, aluminum casting alloys has achieved the best position. It was further demonstrated that laser treatment is a technology of the highest potential and attractiveness in the context of applying aluminum casting alloys for surface treatment.
Abstract: The paper presents the research results on the mechanical properties of aluminum alloy 7020 and its FSW and MIG welded joints. For comparison, alloy 5083 – the most currently used in shipbuilding alloy was chosen as well as 5059 – the new high-strength alloy. Besides, the native material alloys there were investigated their joints welded by FSW and MIG – the same methods as alloy 7020. Welding parameters used for the connection of the sheets made of 7020, 5083 and 5059 alloys were presented. Metallographic analysis showed the correct construction of structural bonded joints.Friction Stir Welding (FSW) – a new technology can be successfully used for butt welding of different types of aluminum alloy sheets. FSW method can be an alternative to traditional arc welding methods, especially MIG, which is the most common method of joining aluminum alloys used in shipbuilding. The research was carried out using a static tensile test in accordance with the requirements of the Polish Standards PN-EN ISO 4136:2011 and PN-EN ISO 6892-1:2010. Flat samples cut perpendicular to the direction of rolling were used. The research was conducted at the temperature of +20 oC.Friction stir welded joints of tested alloys have higher strength properties as compared to MIG welded joints. The 7020 alloy has higher strength properties then alloys 5083 and 5059. The yield stress is higher by 14.8% as compared to alloy 5083, and by 11.7% as compared to the alloy 5059. Plastic properties of alloy 7020 are the lowest, but with reserves meet the requirements of classification societies. The joints welded by FSW of alloy 7020 have the highest strength properties of all researched joints – higher then alloys 5083 and 5059 joints welded by FSW and joints of all alloys welded by MIG.
Abstract: The results of corrosion properties research of aluminum alloy AW 7020 (AlZn5Mg1) welded by friction stir welding (FSW) and MIG were presented. Friction Stir Welding (FSW) – a new technology can be successfully used for butt welding of different types of aluminum alloy sheets. In the paper, the parameters for friction stir welding of sheets made of AlZn5Mg1  alloy were presented as well as parameters for MIG. Metallographic analysis of bonds showed a proper structural construction of both, the FSW and MIG welded 7020 aluminum alloys.The study was carried out in accordance with the requirements of the ASTM G 106. EIS measurement was performed in three-electrode system in artificial seawater (3.5% NaCl). Impedance studies were carried out at the corrosion potential. Changed voltage signal amplitude in the range ±10 mV and frequency range of changes was as follows: 100 kHz – 0.1 Hz. Atlas 0531 EU & IA potentiostat was used for studies.The results of electrochemical impedance spectroscopy are presented in the form of parameters characterizing the corrosion process. Obtained results were statistically analyzed.The electrochemical impedance spectroscopy studies have shown that the joint welded by FSW has better electrochemical corrosion resistance than the joint welded by MIG and the native material – AW-7020 alloy.Original value are received results of the corrosion properties of new method friction stir welded AlZn5Mg1 alloy compared with traditional MIG method and the native material.
Abstract: The aim of this research is to investigate the influence of lead angle, cutting speed and the maximum chip thickness on tool wear in face milling process of compacted graphite iron. Tool failure modes and wear mechanisms for all cutting tools were examined in respect of various cutting parameters and were evaluated on the base of the flank wear. SEM analyses of the cutting inserts were performed and experimental results have been modelled with artificial neural networks (ANN) and regression analysis. A comparison of ANN model with regression model is also carried out. Predictive ANN model is found to be capable of better predictions for flank wear within the range used in network training. The R2 values for testing data were calculated as 0.992 for ANN and 0.998 for regression analysis, respectively. This study is considered to be helpful in predicting the wear mechanism of the coated carbide insert in the machining of compacted graphite iron.