Abstract: The use of modern materials, such as composite materials, enabling the production of new or modifying the existing design solutions, and improvement of their technical characteristics in their use in the design, engineering and manufacturing process, allows achieving an improvement of their endurance, physical and chemical properties to match the features and functionality that comply with assumptions. In research studies, it has been proposed to systematize and formalize features in the context of modeling and fabrication of objects created on the basis of structural fiber composites. The result of the study and analysis will be precisely adapted algorithm of the design and construction process and also fabrication of the structural objects made upon using composite materials. The process of multicriteria optimization and stress analysis upon using CAx-class software will enable to reduce the probability of failure or damage to the modified component.
Abstract: Recently, intensive research activity in the application of guided waves (GWs) for structural health monitoring (SHM) has been observed. Interdigital Transducer (IDT) is one of the types of transducers used for generating GWs. The main advantages of such transducers include their ability in generating directional and mode-selective waves. The parameters of IDTs have to be adjusted for the excited wavelength. Some geometric parameters as well as the properties of materials used for manufacturing transducers may be defined using widely known analytical relationships . However, in order to accurately determine the parameters of the IDT, numerous simulations and their experimental verification are required . The paper presents a novel, time efficient approach to the virtual prototyping of complex shaped transducers. The proposed procedure consists of the following four steps: (1) designing a transducer based on analytical relations, (2) approximate numerical simulations of designed transducers with a custom-made, computationally efficient code for screening tests, (3) detailed numerical tests employing the multiphysics Finite Element Method (FEM) for the developed IDT design and (4) experimental tests.
Abstract: There at machining of parts on machining centers, different kinds of drills can be used for the same purpose. The best of them cannot be selected without necessary analysis. For that reason, different drills and their possibilities at machining of different length holes in parts are explored and their influence on machining results is showed in the paper. Because not only kind of a drill, but also the possibilities of a machine tool influence the final results, interaction of these components is analyzed.
Abstract: It was shown that selection of a tool and cutting rates has strong influence on machining cost. Influences of different expense components in a machining company are analyzed and it is shown how all of them influence of production cost and the smallest cost is searched. It is shown that adequate selection of tools for machining and rates of cutting can markedly decrease the machining costs.
Abstract: Friction stir welding (FSW) is a recently developed method for making a rigid joint of materials that are otherwise hard to weld. It uses a rotating tool for softening the materials without reaching the melting point, and while the tool is moved along the joint line the plasticised material from the joined materials is mixed and hardened producing the solid phase bond. The article presents the authors’ method for monitoring the Friction Stir Welding (FSW) processes with use of thermal imaging camera.FSW method is a new method and there are only few tools to assess the quality of the process, especially on-line, that is in the making of the weld. The authors propose a method for monitoring the FSW process using hybrid vision methods that is acquisition of the image of the weld with the use of a thermal imaging camera and visual band camera. The paper presents selected results of research performed using infrared imaging channel.The recorded thermograms allow identifying the weld defects and non-compliances during the process and using a thermal imaging camera, also allow detecting subsurface defects. The obtained results indicate its potential practical application but still the described application is to be further developed to become a part of a hybrid system for monitoring the FSW processes.
Abstract: The paper is devoted to the permanent joining of powder parts by the pulsed electromagnetic field. The possibility of such joining was proved experimentally and testing the obtained samples. The method of permanent joining of powder parts employing technologies of the pulsed electromagnetic field is the most effective for joining powder parts with relatively high copper content (more than 10%) and when the thickness of powder parts is in the range from 2 to 10 mm. Using a concentrator of the electromagnetic field allows increasing pressure in a relatively small zone up to 2...3 times, which significantly increases the deformation of the material of joined parts and, consequently, the reliability of joints.
Abstract: Commonly used as a finishing operation, lapping has been applied for achieving ultra-high finishes and close tolerances between mating pieces. It can be carried out by applying loose abrasive grains between work and lap surfaces, and causing relative motion between them resulting in the finish of a multi-directional lay.The activity of grains (sliding and rolling) in the working gap causes not only the removal of the material but also a rise in the temperature of the lap plate. The authors of this work analyse the influence of the temperature of the elements of the lapping machine executory system on the results of the lapping process stimulated applying ABRALAP 380 lapping machine the executory system of which consisted of three working conditioning rings. The temperature of the elements of the executory system was measured employing Thermo Gear G100 infrared camera. The workpieces were ceramic (Al2O3) valve sealing parts. After grinding, they were being lapped during 15 and 20 minutes. Machining was started following 10, 140, and 270 minutes of the working time of the machine (tp). The abrasive mixture was boron carbide powder with grain number F400/17, mixed with kerosene and machine oil with grain concentration equal to m = 0.25. Two sets of lapping parameters were executed:lapping pressure p = 0.051 MPa, and lapping speed v = 27 m/min;lapping pressure p = 0.03 MPa, and lapping speed v = 38 m/min.The rate of material removal in g and mm and roughness parameters Ra and Rk of the surface were analysed.The conducted studies showed that the temperature of the elements of the machine executory system affected only parameter Ra which is higher for the surfaces that were processed starting from the 270th minute of the working time of the machine. Only a slight increase in the values of parameter Ra was observed. It can be caused by a change in conditions for the process of material removal due to different properties of grain carrier under a higher temperature. Its viscosity decreases with an increase in temperature, which implies direct interactions between the plate and workpiece surface. Normally those two surfaces interact indirectly via abrasive grains. The rest of the tested lapping results were independent of the temperature of the elements of the lapping machine executory system. The values obtained under different temperatures were almost the same.
Abstract: In order to enhance the uniformity of cladding copper layer distribution over the bimetallic bar perimeter and length, the shape of the classical horizontal and vertical oval passes were modified. The rolling was carried out in the designed modified elongating grooves. The round Al-Cu bimetallic bars with an outer diameter of 22 mm and a copper layer share of 15 and 30%, after explosive cladding, were rolled on a D150 two-high shape mill. As a result of rolling in 4 passes, bars of a diameter of about 16.0 mm were obtained. By applying the modified grooves to the rolling of Al-Cu bimetallic bars, the stability of the rolling process was improved, whereby, finished bars with a uniform and tight cladding layer distribution over the core and small diameter dimensional deviations was obtained.
Abstract: Burnishing hard materials can be used as an alternative finishing process. This paper presents the results of burnishing hardened steel. The article discusses surface deformation that occurs during this process and depends on the selected parameters of the geometric structure of the force applied for surface burnishing.
Abstract: The paper presents results of experimental studies on the effect of non-uniform temperature distribution over the metallic charge length on the energy parameters change during round bars rolling process. Experimental tests were conducted on the D370 Continuous Shape Mill in industrial works. From the tests carried out, it has been found that the main cause of occurrence of the non-uniform distribution of temperature over the charge length is the process of heating the metallic charge in the walking beam furnace. During rolling of bars from metallic charge with non-uniform temperature distribution over its length, changes in friction conditions in the zone of contact between the band and the rolls and in the plastic properties of steel being rolled occur. For decrease temperature during metallic charge rolling process about 100 °C (Fig. 2) in walking beam furnace, increase of rolling torque and total rolling power about 30% during rolling process metallic charge in first continuous shape mill stand was observed.