Properties of TiN/CrN superlattice hard coatings deposited by reactive magnetron sputteringAngelov, M; Cholakova, T; Kolaklieva, L; Kakanakov, R; Chitanov, V
doi: 10.1088/1757-899X/400/3/032001pmid: N/A
Nanostructured TiN/CrN superlattice hard coatings were deposited using a reactive closed field unbalanced magnetron sputtering in the presence of additional anode for higher plasma ionisation degree at temperatures lower than 240°C. Coatings with three different bilayer periods (Λ) of 16 nm, 20 nm and 24 nm with applying a moderate substrate bias were obtained. The effect of bilayer period on the mechanical and tribological properties of the coatings was investigated by atomic force microscopy, nanoindentation, micro scratch and ball–on–disk wear tests. All the coatings possessed enhanced hardness, decreased coefficient of friction, improved adhesion and higher toughness in comparison with single-layer and gradient-composition hard coatings. The highest hardness value of about 30 GPa and elastic modulus of 360 GPa were measured for the coating with bilayer thickness of 24 nm. The friction coefficient against the diamond tip was within the range 0.2 for Λ = 20 nm to 0,208 for Λ = 16 nm. The calculated wear rates against 3/16 inch alumina ball were within the range from 1,045.10−6 mm3/N.m for Λ = 24 nm to 1,955.10−6 mm3/N.m for Λ = 16 nm. The static coefficient of friction μSS against polished SS plate was μSS = 0,268 for Λ = 24 nm, up to μSS = 0,301 for Λ = 16 nm, as the reference TiN layer possesses μSS = 0,218. The wetting angle of the coatings against deionised water was between 91° for Λ = 16 nm to 85° for Λ = 24 nm.
The manufacturing method of the composite worm gear housing using the cold injectionBaier, A; Herbus, K; Ociepka, P
doi: 10.1088/1757-899X/400/3/032002pmid: N/A
In the work the innovation manufacturing method of the composite worm gear housing of the electric power steering system was presented. Modification of the worm gear housing of the electric power steering system consisted in changing the material from which it will be manufactured. Until now, gear housings were made of aluminum by hot injection method. The present works aim at using the pDCPD material and the cold injection method into manufacturing the new generation of the worm gear housing. The planned change was aimed at eliminating the machining process of the cast aluminum body and reducing its mass. In the work was assumed, that the assembled worm gear housing, with all cooperating elements, will be manufactured using the cold injection method. As a result of the manufacturing process the finished product in the worm gear form of the electric power steering system will be obtained. In addition, the geometrical form and the dimensions system of the support elements were determined in relation to the assembled worm and the worm wheel together with the bearing system. The presented method allows eliminating the expensive and time-consuming process of machining of the molding gear housing.
Theoretical researches on the durability of composite materials with metallic and non-metallic matricesCaliman, R
doi: 10.1088/1757-899X/400/3/032003pmid: N/A
The study was designed in the sense of deepening the data on composite materials, examined in terms of their physico-mechanical properties, with particular emphasis on laminated plates subjected to dynamic stresses. The paper aims to address the procedure of solving the finite element system equations system on the “multi-grid” system - called the Fast Finite Element (FFM), developed by Structural Research and Analysis Corporation and currently integrated in the Cosmos software package, having the following advantages that are clear from the specification of a number of features: number of plate elements: 19113; number of nodes: 19650; number of equations: 117900; requiring a low disk swap space.
Analytical method for determining the durability of fiber reinforced composite materialsCaliman, R
doi: 10.1088/1757-899X/400/3/032004pmid: N/A
The durability of composite materials with metallic and non-metallic matrix can be calculated using both the uniaxial and biaxial loading of the composite, following the wear phenomenon that occurs in these cases. At the same time, this mode of loading of composite material offers multiple ways of analyzing crack resistance, because the wear phenomenon characteristic of these materials is composed of both the wear of the matrix and, in particular, the sliding wear and the crack-breaking behavior of the fibers. This paper proposes to approach the procedure of solving the specific equation systems with regard to the crack resistance, using for this purpose a composite panel with a rectangular surface, with a height w = 60 mm and a thickness t = 18 mm, subjected to loads variables. The model is considered to be loaded under a tension σct (MPa), both above and below the crack line.
Effects of high straining in copper strips processed by multiple direct extrusion and subsequent rollingComaneci, R; Bujoreanu, L-G; Popa, M
doi: 10.1088/1757-899X/400/3/032005pmid: N/A
As a novel severe plastic deformation (SPD) method, multiple direct extrusion (MDE) has been proposed as a new technique based on conventional deformation, consisting in repetitive extrusion processes of initial-squared cross-sectional workpieces, followed by transversal cutting, overlapping the resulting halves and resuming the extrusion by reinserting samples in the same die. Four cycles of MDE (route B) were applied to commercial copper and the potential for grain refinement and improvement in mechanical properties were evaluated. Because after the 3rd pass MDE(route A) a buckling instability was noticed, a series of comparative experiments by simple and combined rolling (R) and MDE, respectively, were undertaken. Tensile testing conducted at room temperature using a computer-controlled testing machine was carried out to evaluate the mechanical properties after each MDE and/or R cycle. Tensile strength and elongation at fracture after MDE, R and MDE + R, respectively, were analysed. It was found that after MDE cycle (route B), tensile strength is more than two times higher than that of the initial state and the elongation at fracture decreases not less than 25%. Combining MDE and R does not give a new increasing in strength that remains almost the same but decreases elongation at fracture.
Molding of auxiliary elements for molding of the power steering gear’s polymers body made of PDCPD materialGrabowski, L; Baier, A; Sobek, M
doi: 10.1088/1757-899X/400/3/032006pmid: N/A
Every year the polymer and composite materials are being used in a growing number of elements using in automotive industry. During research for a modern solution to replace commonly used steering housings, solutions have been sought to reduce weight and cost of production. Bodies are made of traditional materials, such as steels or aluminum, which is why the choice was on modern polymer materials from the PDCPD materials group. Polymer composite materials loom large increasingly important role in the automotive industry. Materials from the DCPD and PDCPD group have been nowadays used to produce elements of the external surfaces of vehicles, like bumpers or parts of body of a car. However, regarding to a very good mechanical property, it was decided to use the PDCPD material as the body material of the passenger car steering system body. The technology of “wraping in a casting process” of the whole worm and wormgear assembly with polymeric material will be applied. In this process, the elements will be pre-set(arranged), will be encapsulated with the elements of the mold and the casting process will be carried out. The prerequisite for a correct implementation of the process is to keep the mold from leaks of fluid polmere material. This would not be possible without the use of auxiliary elements (fixing elements). Therefore, the manufacturing process of bodies made of PDCPD material requires an auxiliary element, without which the casting could not take place. These elements are also made of PDCPD material. At the beginning, CAD 3D forms were prepared. The next step was to design the mold making process. After the molds were formed, it was possible to proceed with the casting process. The modling process of the PDCPD material was associated with a number of tests required to determine the casting parameters. Process is quite different from the traditional casting of metal materials. Also, the casting process parameters, temperatures, pressures could influence the correct process of casting. Research and results were described in detail in this paper.
Estimation of the power of a MFC type piezoelectric used for electric energy recovery from vibrationsPlaczek, M; Brzezny, M
doi: 10.1088/1757-899X/400/3/032007pmid: N/A
One of the possibilities of piezoelectric transducers applications are systems for electric energy recovering from mechanical vibrations. The obtained amount of electric energy is not big but sometimes it is enough for power supply some elements such us microcontrollers or other electronic devices with low energy consumptions. The main advantage of piezoelectric transducers used as power supply elements is that there is no necessary to replace batteries or use wires. In this paper results of laboratory tests of Macro Fiber Composite piezoelectric transducer that is used for electric energy recovering from mechanical vibrations are presented. The aim of the presented work was to estimate the maximum power of the MFC transducer that can be used as power supply for some electronic device. To do that a series of laboratory tests was done. The MFC transducer was glued on the cantilever beam surface. The beam’s vibrations were excited using the second one MFC transducer. The tested MFC transducer was electrically loaded with a voltage divider of various resistances. The generated electric voltage was measured and electric current was calculated to estimate the maximum power of the piezoelectric MFC transducer.
Influence of fabrication imperfections on dynamic response of a sandwich composite panel of a ship deck structureSavin-Barcan, M; Beznea, E-F; Chirica, I
doi: 10.1088/1757-899X/400/3/032008pmid: N/A
The dynamic behavior of bebonded sandwich plates at the skin/core interface is analysed. The finite element code COSMOS/M is used to analyse natural frequencies and mode shapes of the sandwich plates with a ellipse shape debonding area. The delamination model has been developed by using the surface-to-surface contact option. In case of surface-to-surface contact, the FE meshes of adjacent plies do no need to be identically. The influence of the diameters ratio of the debonded area, on the modal parameters of clamped sandwich plates is investigated. Parametric calculus of the sandwich plate, having various diameters ratios (Dx/Dy = 0.5; 0.75; 1) for delaminated area, have been considered. It has been observed that all the above mentioned ratios are contributing to the changes in dynamic responses of the sandwich plate.
Researches regarding injection moulding of polymeric products in moulds with micro-profiled surfacesSerban, D; Opran, C G
doi: 10.1088/1757-899X/400/3/032009pmid: N/A
Injection moulding is one of the most commonly used manufacturing processes for composite polymeric products, with high challenges. Dimensional accuracy, optimal mechanical-physical properties as well as very good aesthetic of the polymeric products are requiring a precise controlled injection moulding system. The mould precision influences the product’s tolerances and the good functioning of the injection moulding system. The mould surfaces are important for aesthetic but also for filling, packing and de-moulding of the product. In this paper we present an analyse of 4 different technologies for manufacturing the micro-profiled mould surfaces of a folk motive pattern from Neamţ County Romania and few geometric figures on the direction and perpendicular on the direction of the flow, with details of 100, 250 and 500 μm with height from 10 to 100 μm: high speed milling, electrical discharge machining, laser engraving and chemical etching. The goal is to find out the applicability domain for each technology, economic and precision criteria. The experiments consisting in building the micro-profiled surfaces mould and in injection moulding a recycled re-granulated polystyrene basis polymer evidenced the cost / precision ratio for each technology and which one is better economically suited depending on the requirement.
The alternative manufacturing process of the mechanism housing. A PDCPD based housing of the power steering systemSobek, M; Baier, A; Grabowski, L
doi: 10.1088/1757-899X/400/3/032010pmid: N/A
The automotive industry is one of the largest branches of the market. Directly behind the armaments and aircraft industries is the most dynamically developing area of searching for new engineering solutions. The search direction is usually related to the need and needs to meet increasingly high safety requirements and growing customer requirements. The task of searching for a new engineering solution seems to be even more difficult considering the assumptions that the new solution will meet. These are not only assumptions related to the nature of the product itself. A very important role in the whole process is covered by the financial aspect of the entire undertaking. Many elements of motor vehicles are very intricately designed nowadays. It is directly related to the increasing care for the user’s safety. For a product to be competitive on the market, however, it must still have the right price. Therefore, new solutions for the market must be characterized by an appropriate price/quality ratio. This assumption guided designers when designing new solutions. The automotive industry is very demanding. The production of parts for the needs of this branch of the market involves the fulfilment of very high requirements regarding the class of components performance. This allows ensuring the good cooperation of components in very difficult conditions that accompany the work of the vehicle. Usually, to achieve the appropriate accuracy class, for example, a surface processing should be used. In the case of car parts, in the production process of which machining is involved, a significant increase in the product price should be expected. The machining process, despite very sophisticated and advanced technologies, is still relatively time-consuming. The additional time allocated to this process translates directly into the cost of the target product. In the paper titled “The alternative manufacturing process of the mechanisms housing. A PDCPD based housing of the power steering system” the process of an alternative method of manufacturing the housing of mechanical systems on the example of the power steering housing was described. The developed system eliminates the machining process. During the carried-out research, the main focus was on developing the casting technology of the gear housing using a two-component composite material. Also, the paper describes specially designed and constructed test stand for casting the body and the process of preparation of individual components previously made from PDCPD material.