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The purpose of this research is working out of a new forming technology of flat parts with ribs from magnesium alloys with the application of a three-slide forging press (TSFP) for the aircraft industry.

New possibilities of forming aviation parts with ribs gives the application of a prototype TSFP. This press consists of three moveable tools and has wider technological possibilities than typical forging machines. It was assumed that this machine (press) application would allow for obtaining ribbed flat forgings from magnesium alloys of good functional and resistance qualities. A characteristic feature of such forgings forming is the working movement of two side tools, which upset the billet in the form of a plate; the result of their action is forming of one or more ribs in the plane central part. It is possible to use the upper punch to form appropriate rib outline. Theoretical research works based on simulations by means of finite element method were conducted for three cases of the process: semi-free forging of parts with one rib, semi-free forming of forgings with two ribs and forging in closed impression of parts with one rib of triangular outline. The first experimental tests were made on a TSFP for the variant of semi-free forging of parts with one rib.

Research results show that there exists the possibility of realization of forming process of parts with ribs according to the conception assumed by the authors. Positive results of theoretical analyses justify the purposefulness of conducting experimental verification for the proposed theoretical solutions of the forging processes of parts with one rib of triangular outline and with two ribs.

Production of flat parts with ribs from magnesium alloys basing on the worked out by the authors’ technology will allow for improving functional and mechanical properties of parts and for lowering their manufacturing costs. At present, such aviation parts are imported to Poland in the form of casts, which are expensive and not always fulfill the requirements. Additionally, large amount of machining at manufacturing of this type of parts generate larger price at their production.

Forging technology of parts with ribs in a TSFP is unique on a world scale. The advantages of this technology are the process material savings and better resistance properties of the formed forgings with ribs than parts obtained in a traditional way.

The purpose of this study is to report results of the qualitative assessment of AZ31 aircraft brackets with a triangular rib produced by a new forging method with respect to their structure and mechanical properties.

The paper reports the results of qualitative tests for AZ31 magnesium alloy aircraft brackets with a triangular rib produced by a new forging method. These ribbed parts were formed on a forging press equipped with three moving tools. The produced aircraft brackets were subjected to qualitative tests. Their cross-sectional microstructure was examined using the light-field technique. The mechanical properties of ribbed parts were determined in a static tensile test and by hardness measurements on the surface of the part. The following variables were determined: tensile strength Rm, yield strength R0.2, elongation A5 and hardness.

The results of qualitative tests provide significant information about produced aircraft brackets with a triangular rib, i.e. microstructure in three key regions of brackets and their mechanical properties.

The method will enable producing magnesium alloy aircraft brackets with a triangular rib. The application of the method for aircraft brackets developed by the authors of this paper will result in higher product quality and reduced production costs. The paper demonstrates the practical application of this technique by presenting a finished aircraft bracket and the results of complete qualitative tests.

The originality of this paper lies in the presentation of a new, innovative method for manufacturing aircraft brackets with a triangular rib. This method is unique on a global scale, and its assumptions have been granted patent protection.

This paper aims at working out an innovative technology of aircraft brackets with a rib of a triangular outline manufacturing from magnesium alloy AZ31 based on forging process.

Theoretical analysis of the assumed forming process of brackets with a rib of a triangular outline was made on the basis of computer simulations in software Deform 3D, basing on finite-element method. Research works were conducted for a magnesium plate from magnesium AZ31 alloy. Considering calculations, the scope of technological parameters guaranteeing the process proper course and good quality of the product was determined. Theoretical results were verified using a three-slide forging press.

The experiment’s results confirmed the effectiveness of the worked-out technology and the rightness of its application at manufacturing of brackets from non-ferrous metals used in the aircraft industry.

The main aim of the worked-out method is manufacturing of aircraft brackets from light metals alloys, e.g. magnesium alloys. This technology can be applied for plastic forming of flat parts with ribs of a triangular outline. Manufacturing of aircraft brackets, basing on that worked out by the author’s technology, will allow for the improvement of products’ quality and reduction of their manufacturing costs.

The originality of this paper is based on the presentation of a new, innovative manufacturing technology of brackets with a rib of a triangular outline. The presented method is a unique one at a national (Poland) and global scale, and its assumptions underwent patent protection.

The purpose of this paper is to determine time-to-ignition of magnesium alloy chips and the ignition-preceding stages as well as to examine chip morphology. The tests were conducted according to the following pattern: directly after a milling operation, after ignition using a special test stand located outside the machine tool and after intensive oxidation which prevented ignition.

Milling is a machining process widely used in the manufacturing of various parts that are applied, e.g. in the aircraft industry. Milling is used for both roughing and finishing machining. In the dry machining of magnesium alloys, spontaneous ignition can occur; therefore, the analysis of chip temperature in the cutting area is of great significance. Additionally, time-to-ignition and chip morphology are crucial when considering the safety of magnesium alloy machining processes.

The experimental results demonstrate the effect of parameters of the milling process on time-to-ignition of chips made of magnesium alloys AZ31 and AZ91HP. The experiments also involved examining the morphology of a selection of chips produced at the maximum cutting velocity vc and feed per tooth fz. In addition, we analysed the morphology of both ignition products and chips subjected to high temperature where ignition did not occur.

Based on the time-to-ignition and chip morphology results, it is possible to indicate both safety levels in machining and the efficient range of parameters in the milling of aircraft parts made of magnesium alloys.

The paper presents a new approach to assessing safety in milling operations. The results of the tests of chip flammability (time-to-ignition) which were run at a special test stand placed outside the machine tool enabled determination of both safety and efficiency range of the milling process.

This paper presents the results of mean unit weight of chips and their time to ignition measured on a test stand specially designed for this purpose. In addition, the temperature of chips in the cutting area and the morphology of chips produced in HSM milling (as a temperature indicator in the cutting area) are investigated. Also, different fractions of chips produced in the dry milling of Mg alloys AZ31 and AZ91HP by a PCD end mill are examined. Finally, the paper presents conclusions and recommendations with regard to safety and efficiency of dry milling processes for the aforementioned magnesium alloys.

Milling can be used as a finishing operation, particularly when using PCD end mills. The application of this mill type isparticularly important when producing different machine and device components, especially in the aircraft industry. What can occur in dry machining operations is self-ignition. It is therefore justified to investigate chip temperature in the cutting zone, to classify produced chip fractions and to determine their mass. Safe ranges of technological parameters can be additionally determined based on metallographic analysis of chip edge partial-melting.

The experimental results helped determine the effect of technological parameters of milling on chip temperature in the cutting zone, chip mass and fragmentation and chip morphology images.

The results reported in this work are innovative in both cognitive and practical aspect. The authors are convinced that this work can contribute to overcoming the mistrust of industrial practitioners toward dry milling of Mg alloys, and also with respect to the application of relatively higher cutting speeds in dry milling of these alloys than it is common practice in industry today. The study investigates the problem of safety in dry milling of Mg alloys. The study was motivated by the milling process itself and the formation of broken chip, which causes a significant change in the character of heat transfer.

The paper presents a method for multi-criteria safety assessment in dry milling operations. Safe and effective parameter ranges are defined with respect to chip temperature in the cutting zone, fraction number and chip mass.

In order to improve the engine reliability and efficiency, an effective way is to reform the turbine blade tip conformation. The paper aims to discuss this issue.

The present research provides several novel tip-shaping structures, which are considered to control the blade tip loss. Four different tip geometries have been studied: flat tip, squealer tip, flat tip with streamwise ribs and squealer tip with streamwise ribs. The tip heat transfer and leakage flow are both analyzed in detail, for example the tip heat transfer coefficient, tip flow and local pressure distributions.

The results show that the squealer seal and streamwise rib can reduce the tip heat transfer and leakage loss, especially for the squealer tip with streamwise ribs. The tip and near-tip flow patterns at the different locations of axial chord reflect that both the squealer seal and streamwise rib structure can control the tip leakage flow loss. In addition, the analysis of the aerodynamic parameters (the static pressure and turbine efficiency) also indicates that the squealer tip with streamwise ribs obtains the highest adiabatic efficiency with an increase of 2.34 percent, compared with that of the flat tip case.

The analysis of aerothermal and dynamic performance can provide a reference for the blade tip design and treatment.

The purpose of the present paper is to develop a new technology for producing magnesium alloy twin-rib aircraft brackets by the forging method.

An overall description of magnesium alloys is given, with particular emphasis placed on magnesium wrought alloys that are used in the aircraft industry. Methods for producing ribbed brackets are discussed and the location of these parts in aircraft structure is described. The forging process for producing AZ31 magnesium alloy twin-rib brackets was modelled numerically, and selected results of the simulations performed are presented. The simulation results were then verified under laboratory conditions using a three-slide forging press equipped with three movable working tools. It was assumed that the use of this machine would allow for obtaining twin-rib aircraft brackets with improved both functional and strength properties compared to the production methods used so far.

The results demonstrate that the method developed by the present authors permits the production of twin-rib brackets. Positive theoretical results and preliminary experimental results prove that it is justified that the research on magnesium alloys used in the aircraft industry be continued.

The production of twin-rib aircraft brackets from magnesium alloys by the technology developed by the present authors would lead to enhanced product quality with simultaneous reduction in production costs (reduced labour costs and material consumption as well as increased process efficiency). At present, magnesium alloy aircraft parts, mainly obtained from semi-finished products imported to Poland, are produced by casting and machining methods. They exhibit, however, much worse properties than elements produced by metal forming methods. In addition to that, the application of machining in the production of these part leads to higher production costs.

The originality of this study stems from the presentation of an innovative metal forming technology for producing twin-rib brackets. This method is unique on a global scale, and its basic assumptions have been granted patent protection. Also, the originality of the study stems from the fact that brackets are made from magnesium alloys, as these light metals are considered the future of structural materials used in the aircraft industry. Given the above, the research on developing the technology for producing parts made from these alloys using a three-slide press is justified.

The purpose of this paper is to augment heat transfer rates of traditional rib-elements with minimal pressure drop penalties.

The novel geometries in the present research are conventional cylindrical ribs with rounded transitions to the adjacent flat surfaces and with modifications at their bases. All turbulent fluid flow and heat transfer results are presented using computation fluid dynamics with a validated v2f turbulence closure model. Turbulent flow characteristics and heat transfer performances in square channels with improved ribbed structures are numerically analyzed in this research work.

Based on the results, it is found that rounded transition cylindrical ribs have a large advantage over the conventional ribs in both enhancing heat transfer and reducing pressure loss penalty. In addition, cylindrical ribs increase the flow impingement at the upstream of the ribs, which will effectively increase the high heat transfer areas. The design of rounded transition cylindrical ribs and grooves will be an effective way to improve heat transfer enhancement and overall thermal performance of internal channels within blade cooling.

The novel geometries in this research are conventional cylindrical ribs with rounded transitions to the adjacent flat surfaces and with modifications at their bases. The combination of cylindrical ribs and grooves to manipulate the turbulent flow.

Aircraft structures and in particular thick wing structures comprise ribs 2 of zigzag formation, Fig. 2, assembled in such manner as to form upper and lower reticulated frames which are spaced apart by posts 4 and are directly secured to the outer covering or skin 1 of the wing or other structure. Longitudinal booms 3 are also secured to the outer covering and to the ribs at the points of inter‐attachment thereof, Fig. 6. Ribs 2 are of channel section shaped at the bends to form flats 2a and to form recesses to allow passage of the booms 3. Adjacent ribs are attached to each other and to the booms at each junction by straps 5, Fig. 5, bent to the shape of the rib angle at 5a, and to that of the underside of the boom at 5b. Parts 5a of opposed straps are introduced between flats 2a of the ribs, the strap extending under the rib channel and then upwardly to connect with the boom, Fig. 6. Tubular posts 4 are secured to flats 5a, Fig. 5, of straps 5 by flanges 6, Fig. 2; the joints may be stiffened by additional gussets such as 7.