Abstract The purpose of this study was to describe dynamics of missile based on bibliography, simplify the model to the easiest form, and verify it with the use of a designed laboratory stand. Next, a simple control system of the missile was designed. The stand is prepared for didactic purposes. A mathematical model was derived by applying Newton's second law together with the earth's coordinate system and the base coordinate system. Parameters of the actual rocket model were determined using the created laboratory stand. Synthesis of the rocket roll system was designed using Simulink PID Tuner application (MathWorks, Inc. Natick, Massachusetts, USA). A control system was based on a proportional-integral (PI) regulator. The designed control system was subjected to simulated tests in MATLAB Simulink (MathWorks, Inc. Natick, Massachusetts, USA).
Abstract This paper discusses the effect of pressure on the content of microvoids and defects inside laminates fabricated under different pressures, by vacuum methods. Two basic vacuum methods resin transfer molding (RTM) and vacuum bag method were used in this paper. A glass mat with an alignment angle of (0□/90□) and a mass of 450 g/cm2 was used to produce the laminate, and a polymer resin was used as the matrix. Special attention was paid to the technological parameters of both processes. A mathematical analysis of the most important parameters which include flow rate, permeability, and gelation temperature has been carried out. In addition, the resin temperature is used to reduce the viscosity of the resin to facilitate its flow through the reinforcement, and in the final stage of production to control the chemical reactions occurring in the mold. The pressure is chosen so that the resin flow is continuous. The synchronization of these two parameters and the measurement of the time in which they occur are called the “cure cycle”. In the final step of the study, the composite was subjected to a static tensile test, using specimens of two different dimensions (scale effect) to evaluate the effect of microvoids and microcracks created by the processes on the strength of the material.
Abstract In this paper, we analyze the nonstationary heat transfer during growth of epitaxial layers in epitaxy reactors from the gas phase. Based on this analysis, we formulate several recommendations on organization of heating of the growth zone for increasing homogeneity of epitaxial layers. We introduce an analytical approach for analysis of heat transfer during the growth of epitaxial layers from the gas phase. The approach gives a possibility to simultaneously take into account the nonlinearity of heat transfer, as well as changes of their parameters both in space and time.
Abstract In this paper, an approach to increase integration rate of elements of a comparator in track state was introduced. Framework the approach a het-erostructure with special configuration was consider. Several specific are-as of the heterostructure should be doped by diffusion or ion implantation. Annealing of dopant and/or radiation defects should be optimized.
Abstract The paper presents the method of approximating curves with a single segment of the B-Spline and Bézier curves. The method for determining a single curve segment using the optimization methods in the CATIA environment is shown. The algorithms of simulated annealing and design of experiment are used for optimization. For the same purpose, a new original procedure for determining the distance between the given curves using explicit parameters in the CATIA environment was also used. This approximation of the cyclic curves results in the curve oscillation as shown in the examples. The results show that the approximation method with Bézier curve using control points as “free” points can be applied to obtain the best results of approximation.
Abstract In recent years, a rapid increase in the use of three-dimensional (3D) printing technologies in medicine, especially in the manufacturing of the diagnostic models, can be observed. In some cases, there is a need to fabricate transparent models that allow visualization of internal structures of the object. Unfortunately, techniques used to manufacture such models are often very expensive and time-consuming. The above-mentioned issues were the motivation for developing a new method of fabrication transparent models for visualization of internal structures for planning surgical treatments. This paper presents the process of making transparent models using the newly developed method – the stacked layers method. In order to compare this new method and one of the most common 3D printing technologies – fused deposition modeling (FDM) – the models for two medical cases using both of these methods were fabricated. As a result of this work, it can be concluded that the stacked layers method provides faster and cheaper way of making transparent medical models. The main features of fabrication process that have a huge impact on quality of the models made by new method were pointed. The results of this study suggest that models fabricated with the use of this method can be useful as a diagnostic tool in medical applications for planning surgical treatments.
Abstract This article presents the process of extrusion shape of complex geometry cross-sectional 7039 aluminum alloy for use in aerospace industry. This study aims to characterize the properties of aluminum alloy as structural material and to determine the technological parameters of the indirect extrusion press and their influence on mechanical properties and the microstructure of the final product. It has been proved that the proper choice of parameters in the case of a specific profile extruded from 7039 aluminum alloy allows the manufacturing of products of complex cross-sections and the quality required in aerospace industry.
Abstract The present paper studies and analyzes the low-pressure vacuum carburizing of Pyrowear 53 steel. The carburizing was performed at 921°C. The results after the completion of the treatment process are presented, i.e. microstructure of the surface layer and hardness. The results confirm that carburizing can be effectively used in hardening of the steel.
Abstract This paper describes the process of creating a digital model of spiroid gears used in the defense industry. This is where the precise measurement of the parts with the highest requirements for accuracy is of great importance The construction of a computational model of a physical object was carried out using an optical three-dimensional scanner. Based on the cloud of points obtained in the process of scanning, a spatial digital model reflecting the geometry of an existing element was developed. Polygonization and mesh reconstruction allowed to create a finite element method model that enabled the precise reproduction of the scanned object. The created model was subsequently used to conduct appropriate analysis and simulation to verify the correctness and possible modification of the construction of both elements of spiroid gears: worm thread and face gear.
Abstract In this article, the fundamental questions concerning the diffusion path, in particular, what is the shape of diffusion path in ternary systems and how to approximate it from the initial concentration profile, will be answered. The new rules were found which allow for determining the diffusion path from a known initial concentration of the components. This approximation will allow for designing new materials without a time-consuming numerical simulation of the full system of equations. It is shown that the difference in intrinsic diffusion coefficients determines the up-hill diffusion.
Abstract The development of software applications and the use of VR (Virtual Reality) techniques allow to improve the company’s financial result. The construction of models of robotic stations with robots using Virtual Robot technology allows to determine the time of the machining process. It allows its optimization through the selection of accelerations, tools, tooling strategies, and so on. Determining the time of a technological operation translates into savings. This allows you to decide on the purposefulness of the investment. In addition, modern software add-ons, for example, Signal Analyzer in RobotStudio, allow you to monitor the electricity consumption of a robotic station. The article presents a solution showing how, based on the construction of digital models and the use of VR, we can conclude about the profitability of the investment.
Abstract This article presents a description and methodology for building a kinematics model for the formation of two-wheeled mobile robots transporting a beam using Denavit–Hartenberg notation. The simple and inverse kinematics tasks of this formation were solved. Solutions of kinematics tasks are presented in junction coordinates and global coordinates. The obtained results were simulated using the Matlab–Simulink package together with animation of the solution using a programmed emulator of robot work.
Abstract In this article, a study of nonmetallic inclusions introduced during the casting process of the aluminum–silicon alloy is presented. The samples were investigated using a scanning electron microscope to find the chemical composition and X-ray tomography to check the volumetric content of the non-metallic inclusions. The samples were made from AlSi7Mg alloy, used for car wheels, with 7% weight content of Si, 89% of Al, and 0.3% of Mg. The main goal of our investigations was to find out the chemical composition of the impurities and to identify the stage of the casting process at which the impurities are introduced.
Abstract In the present work, an effect of plasma-forming parameters on light emission during analysis by glow discharge optical emission spectrometry of Ni–Cu model alloys is studied. To evaluate the effects of plasma-forming parameters on light emission, argon pressure was varied in the range between 600 Pa and 1000 Pa under a constant power of 20 W. Moreover, a variation of power at 20 W and 30 W under a constant Ar pressure of 1000 Pa was investigated. An effect of the element content on light emission was found. Namely, for Cu, a monotonic, non-linear increase in measured light intensity with an increasing Cu content was found. Surprisingly, for pure Ni, a lower light intensity was measured as for Ni90–Cu10 (at.%). Possible reasons causing this was listed as: (i) possible effect of hydrogen, (ii) overlapping of lines for Cu and Ni and (iii) self-absorbing of Ni line at 341.574 nm.
Abstract This article presents the possibility of using the replication method to measure selected parameters of the surface geometry. The results of the tests obtained while measuring the replica and surface of the tested object are presented. The obtained results indicate the suitability of using RepliSet F5 to measure the roughness parameters (Ra and Rz), microgeometry tool, and grinding wheel. It has been proven that the replication method using the RepliSet F5 is suitable for chosen parameters of roughness and tool microgeometry measurements. However, it is not suitable for measuring the porosity of a grinding wheel.
Abstract In this study, locally available waste coconut (Cocos nucifera) shells (CSs) were investigated as possible replacement for asbestos-based brake pads. The CS-based brake pad was tested for its physicomechanical properties and compared with a commercial brake pad used as control sample. The results showed that (a) an improved interfacial bonding between the CS particles and the binder as the grain size decreases; (b) the 90 μm grain size sample had better physicomechanical properties than the control sample in all tests except the thermal conductivity and stability tests; and (c) the hardness, compressive strength, and density of the CS-based brake pad decreased with increasing grain size, whereas the absorption properties increased with increasing grain size. The study showed that further reduction of the grain size below 90 μm and matrix impregnation with metals of good thermal conductivity could provide significant improvements to properties of the CS-based brake pad.
Abstract The paper presents the method of determining geometric contact pattern by using the direct computer-aided design (CAD) method for ideal globoid worm gear in which mounting deviations are considered. The tooth contact analysis was performed for all cycle of worm rotation. Based on the results of temporary contact pattern, graphical characteristics of the contact area size depending on worm position were made. A complete analysis of the correctness of gear meshing can be obtained based on presented method. If the worm or worm wheel is incorrectly designed in terms of the geometry, the meshing simulation of CAD models can indicate the collision. Geometric contact pattern analyses were made at two pressure angles of ideal gear. The analysis of the influence of mounting deviations was done against one selected pressure angle and one gear position.
AbstractThe present study investigated the effect of surface roughness on plasma assisted nitriding (PAN) process kinetics of Ni-base alloys. Two model alloys, namely Ni-10Cr and Ni-14Cr-4Al (wt.%) and commercial Rene 80, were examined. To elucidate the effect of surface roughness on nitriding kinetics, three methods of surface preparation were used, (1) polishing up with 1 μm diamond suspension, (2) grinding up to 220 grit sand-paper, and (3)grit blasting. The samples from each type of material were nitrided under the same conditions and investigated after processing. It was found that increase in roughness results in decreasing nitriding kinetics. The decrease of nitriding kinetics depends on alloy chemical composition, namely more complex chemistry resulted in smaller decrease of kinetics. Moreover, grit-blasting was found to be an improper method for surface preparation for PAN. The responsible mechanism for the effect of surface roughness on PAN kinetics of Ni-base alloys was proposed.
Abstract The main purpose of the present study is to verify the possibility of decarbonizing the surface of heat-resistant ductile iron GJS-XSiMo5-1 to provide a significant difference in carbon content between this material and gray cast iron ENGJL-250. In the future, this will allow to increase the diffusion of elements during the creation of the two-layered material using the casting process with materials in a liquid state and solid state. The above method was assumed to solve the problem of defects on turbocharger’s housing in an economically justified manner which occurred in some high-performance premium applications. Evaluation of decarbonized surface quality was investigated by microstructure observation (light microscopy) and alloy elements diffusion (scanning electron microscopy), and hardness measurement and the element content were checked by spark optical emission spectrometry and glow discharge optical emission spectrometry, respectively.
Abstract This paper focuses on the influence of crystallographic orientation on creep resistance of CMSX-4 nickel-based superalloy. The single-crystal rods of CMSX-4 superalloy were manufactured with the use of the Bridgman method at a withdrawal rate of 3 mm/min. The crystallographic orientation of the rods was determined by the X-ray Ω-scan method with OD-EFG diffractometer and the Laue back-reflection technique. The creep tests were performed at a temperature of 982°C and the value of stress σ = 248 MPa. Microstructural investigation before and after the creep test of CMSX-4 superalloy was performed using a scanning electron microscope. The results showed that the distribution of the values of α angle strongly affects the creep resistance of a single-crystal superalloy.
