Papers by Keyword: Insert

Abstract: Despite of the numerous advantages offered by the CFRP tendon, there are still problems to be solved. Among them, finding an effective anchoring method considering the material properties of CFRP constitutes a typically pending problem. Being an orthotropic material, the CFRP tendon presents risk of breakage under forces acting perpendicularly to the direction of the fibers. This implies that a new type of anchor should be developed for the CFRP tendon since the anchorages used for conventional steel strands cannot be readily applied. Moreover, following the growing interest given to the CFRP tendon, research is being relentlessly conducted to develop dedicated anchorages with improved performance. Accordingly, this paper presents an experimental study on the anchor performance of the swage anchorage known to be the most compact among the various types of anchor. The tests revealed that the swage anchor without insert developed about 92% of the tensile strength of the CFRP tendon whereas the swage anchor with metallic winding insert developed 100% of the tensile strength. From these results, it appears that the anchorage with outer diameter of 24 mm develops anchor performance higher than 95% of the tensile performance of the CFRP tendon and can potentially be exploited for post-tensioning.

Abstract: For a set of applications, thin metallic sheets are used in fibre composite materials to reach higher load introduction capacities. The paper deals with a simplified generic problem of this kind. The main subject is the comparison of results of three types of models, namely, a 1D-, 2D- and a 3D version. What can be shown is the fact that results are quite similar with respect to behaviour along the loading direction, but very different in the actual values.

Abstract: Due to their poor machinability, titanium alloys need to be worked at low cutting speeds to prevent a fast tool failure caused by the very high temperatures that are reached at the tool-chip interface. As demonstrated by previous works by the authors, an improvement of productivity for Titanium alloys can be obtained by adopting cryogenic cooling during the machining operations.The present work shows the features of a toolholder specifically designed for cryogenic adduction in turning operations, following Hong’s design guidelines. The paper compares tool life results between traditional and cryogenic rough turning by adopting Grade 5 titanium as the working material. Rough turning is economically more relevant to the machining industry, especially in the aerospace field where generally a large quantity of rough material has to be removed due to the very high buy-to-fly ratio of aerospace components. A full factorial experimental plan was performed basing on typical rough turning parameters. Machining outputs such as forces, roughness, temperatures, friction coefficients were calculated in order to define statistical differences between cryogenic cooling method using the special toolholder and traditional oil water emulsion cooling system.Furthermore, thanks to tool life results the Taylor’s law for cryogenic and traditional cases was calculated and an hypothetical production scenario for Ti6Al4V parts was analysed. An analytical model to calculate production costs and time was built for both cooling methods. A 4-turrets turning centre was considered and cooling methods and costs per hour of machine tool were taken into account in a cost model. The results show that the benefits in terms of tool life offered by liquid nitrogen cooling allows to improve productivity by adopting higher optimal cutting parameters. This improvement, coupled to an increase of tool life, is very significant and allows not only to reduce time of production but also to cover the major costs of liquid nitrogen and have a slight reduction of machining total costs.

Abstract: Titanium alloys, mainly because of their poor thermal conductivity, need to be cut at relatively low cutting speeds to avoid a severe diffusion wear, with obvious negative consequences on the profitability of machining. An important amount of research activities has been done in order to increase productivity in titanium machining operations and one of the most promising solutions is represented by the use of liquid nitrogen as a coolant during the machining operation. The aim of this paper is to compare traditional and cryogenic turning of Ti6Al4V in a region of cutting parameters particularly relevant to the aerospace industry where no previous data are available. The cutting parameters are those typical of titanium alloys rough machining which is considered, cost-wise, the most important operation because, for aerospace components, the so-called Buy-To-Fly ratio can reach values up to 20:1. The experiments have been performed using a full factorial design in order to statistically evaluate, using ANOVA and regression analyses, the significance of the input factors on the process most interesting outputs. The considered input factors are: type of cooling method, cutting speed and feed rate. The main analysed responses are: tool wear, surface roughness, cutting forces, coefficient of friction and chip morphology. The results show the significance of the cooling method on the tool life and that cryogenic machining is able to increase the tool life with respect to wet cutting. On the other hand, the beneficial effect of the liquid nitrogen cooling is reduced at high cutting speed and feed rate. Besides, the results showed that a small but significant reduction can be achieved for both the repulsion force and the coefficient of friction at the tool-workpiece interface.

Abstract: In this paper, the method of resistance spot welding with cover plate was proposed to weld the materials combination of the metal with high resistance and the metal with low resistance, such as steel/aluminum, titanium/aluminum, titanium/magnesium, and steel/magnesium; and the technique of resistance spot welding with insert sheet was proposed to weld dissimilar materials with low resistance and to weld dissimilar materials with high resistance.

Abstract: Fuzzy C-means (FCM) clustering algorithm is one of the widely applied algorithms in non-supervision of pattern recognition. However, FCM algorithm in the iterative process requires a lot of calculations, especially when feature vectors has high-dimensional, Use clustering algorithm to sub-heap, not only inefficient, but also may lead to "the curse of dimensionality." For the problem, This paper analyzes the fuzzy C-means clustering algorithm in high dimensional feature of the process, the problem of cluster center is an np-hard problem, In order to improve the effectiveness and Real-time of fuzzy C-means clustering algorithm in high dimensional feature analysis, Combination of landmark isometric (L-ISOMAP) algorithm, Proposed improved algorithm FCM-LI. Preliminary analysis of the samples, Use clustering results and the correlation of sample data, using landmark isometric (L-ISOMAP) algorithm to reduce the dimension, further analysis on the basis, obtained the final results. Finally, experimental results show that the effectiveness and Real-time of FCM-LI algorithm in high dimensional feature analysis.

Abstract: The paper does the pretreating operation of palm print, the process of which includes lowpass filtering, histogram equalization, binarization processing, edge extraction, corner detection, rotating location and extraction of subgraph ROI. In images done with pretreating, translation and rotation phenomenon of noise level has almost been removed, which benefits the characteristic extraction and identification of palm print. And we finally demonstrate by experiments.

Abstract: According to the problems of slow weighing speed and low precision resulting from sticky foods caking in quantitative packing weighting, the mechanical structure, the circuit system and the software algorithm were designed in this paper. To improve the weighing speed and precision of sticky foods, the double-tube spiral feeding machine and a special structure of scale bucket were adopted in mechanical structure; a programmable AD8555 was used as weak signal amplifier of weighing sensor and a 32-bit microprocessor LP2134 was utilized as the core of the circuit system; the piecewise weighing method, FIR software filter and the differential algorithm are applied to send command to executive mechanism in program design.

Abstract: The traffic signal lights control system automatically controls the statues of the intersection traffic lights and dispatch the traffic vehicles normally that traffic scheduling is an important system and it is the most basic and most important tools in city traffic management. Traffic lights control system made by single chip microcomputer technology has a single working model, low reliability, slow speed, and it can't modify or upgrade online, which is difficult to adapt to changes at different times of the traffic flow. This design of the dual mode of traffic lights control system intelligently controls each intersection traffic lights on and off time in the different period, which will improve the scheduling efficiency of road intersections. The design is based on FPGA with a digital display of traffic lights control system, compile the program design and simulation in Quartus II development environment, and ultimately download to EP2C35F672C6 chip of Altera Company. By the DE2 experiments test platform, the system has stable performance, simple operation, easy to maintenance, high reliability, strong expansibility and good refactoring.

Abstract: Titanium alloys, mainly because of their poor thermal conductivity, need to be cut at relatively low cutting speeds, with obvious negative consequences on the profitability of machining. An important amount of research activities has been done in order to increase productivity in titanium machining operations: high performance coatings and innovative technologies to improve inserts resistance to wear represent promising solutions. In this work, the cutting performance in Ti6Al4V rough turning of an innovative TiAlN coating obtained by Physical Vapor Deposition (PVD) magnetron sputtering and the effects of a Deep Cryogenic Treatment (DCT) have been experimentally investigated and a statistical analysis of the results has been performed. Typical commercially available inserts (TiAlN-AlCrO coated) have been used as a benchmark. Preliminary hardness and thermal conductivity measurements tests have been performed on the three types of tool to determine the differences caused by the different coatings and thermal treatment. The experiments have been conducted using a full factorial design in order to statistically evaluate, using ANOVA, the significance of the input factors on the process most interesting outputs. tool life and other variables of interest with different process parameters. The considered input factors are type of insert, cutting speed and feed rate. The analysed responses are average flank wear, surface roughness, cutting forces, coefficient of friction and chip morphology. The results show that even if friction coefficients are lower for standard tools, innovative inserts exhibit a higher resistance to wear. Taylor’s law parameters of PVD coated tools, with and without DCT have been determined, clearly showing that cryogenically treated tools present higher resistance at higher cutting speeds, mainly due to their superior hardness. In conclusion, it appears that relevant improvements of productivity or profitability of titanium turning can be obtained if an advanced PVD coating, deposited by magnetron sputtering is used on tungsten carbide inserts and if deep cryogenic of the inserts is performed afterwards.