Advanced Materials Research Vols. 816-817

Abstract: Auxiliary frame, as a skeleton of a front and rear axle, in order to improve its performance, this paper takes a SUV auxiliary frame as an example. Make the finite element modeling and do Strength and modal analysis through Hypermesh. Show the previous six order modal frequency, take the idle vibration frequency of engine, the second harmonic vibration frequency and the target vehicle auxiliary frame mode for the target to do modal optimizations.Finally make each order modal of the auxiliary frame satisfy the target, reduce the risk of vibration noise, the incoming road vibrations and enhance comfort of the vehicle.

Abstract: Combined with the structure and operating characteristics of the original type, an optimized structure of elastic tube bundle is proposed. The mechanical properties of the end region of the elastic tube bundle are derived theoretically, and researches are carried out on the vibration and heat transfer characteristics by adopting the method of combination of experiment and numerical simulation. The results show that there exist noticeable improvements for the optimized structure in the four aspects as follows: 1. the bending moment endured in the end section is only 0.159 times of the original tube bundle; 2. the natural frequency is lower than that of the original type; 3. the mean heat transfer coefficient of which is 26% higher than that of the original one; 4. the heat transfer area per unit volume increases by 24.7%. Furthermore, a comprehensive analysis is made on heat transfer performance improvement of the optimized structure

Abstract: Shot peen forming different from shot peening is a metal forming process widely used in aeronautical industry. Different types of tension-tension fatigue specimens after peen forming were tested. The results show that the fatigue life of specimens peen formed with large balls except edges is 35.4% higher than that of unpeened specimens, while the life of the specimens with whole surface peen formed is 23.2% lower than that of the unpeened specimens. In addition, shot peening specimens which have been peen formed as a surface strengthening way can significantly improve the fatigue resistance. Moreover, when the specimen is peen formed except edges, the position of crack source is from the indentation region to subsurface.

Abstract: Friction surfacing is an advanced process of great potential and an enhanced technology in surface modification. It is a solid state process, which allows deposition welding at temperatures below the melting range. The present study is on the coating of stain-less steel on Spheroidal Graphite Iron through the process of friction surfacing. This work explains the perfection obtained through various combination of the parameters used in friction surfacing namely traverse speed, rotational speed and the applied load. Series of test was performed on the friction surfaced work piece. Fine bonding has been accomplished between the selected materials out of the process done with variable combination of process parameters. Mechanical tests like bending test, micro-hardness test and corrosion test were conducted. Appreciable hardness values (200 HRC) have been obtained in micro-hardness test. Bend test performed on the surface revealed good strength and reliability of the bonding. The Corrosion test was conducted to find the suitability of these deposits for chemical pumps, pressure vessels and joints of dissimilar metals. The presence of pearlite and ferrite matrix in the microstructure exemplifies the strength of the bond. These results are expected to find great use for important applications in defence, aerospace, electrical, automobile and many other industrial sectors in the engineering fields.

Abstract: To meet the requirement of microelectronic industry, ceramic/polymer composite films made of CaCu₃Ti₄O₁₂ (CCTO) powder as filler and PVDF copolymer as matrix were prepared by solution casting method. The dielectric properties (DP) and morphology of the films were studied by impedance analyzer and scanning electron microscope (SEM) respectively. The dielectric constant could reach 23.96 and loss 0.1082 when mass fraction of CCTO is 50% at 100 Hz. SEM results show that CCTO particles dispersed well in the PVDF matrix. At last, three composite models were used to predict the dielectric constant of the composite films and it is proved that Yamada model fits the experimental data well.

Abstract: The broken-explosive warhead for back deep underground target and airport runway hard target has a unique advantage. Through analyzing hard target characteristics of the concrete , process using ANSYS/LS-DYNA software to break-explosive warhead of a warhead forming process and penetration into concrete target is studied by numerical simulation. Experiments show: the simulation results are accurate. A warhead on concrete penetration and expanding role better, open a channel for level two warhead implement efficient damage. To counter this deep underground and airport target road of hard target penetration has a certain application prospect.

Abstract: Because of inefficiency of many tests needed in GMI research, this paper put forward the sweep frequency measurement method to implement the measurement of GMI effect under multi frequency at the same time in a single test. Experiments proved that the GMI effect curves which are measured by the sweep measurement method are consistent with other method's results, and the sweep frequency measurement method can greatly reduce the time of GMI test and improving the efficiency of the test.

Abstract: In this paper, a water-lubricated hybrid with four stepped recess supporting a high-speed spindle system is studied. A two-dimension finite element method considering turbulence effect and the relationship between temperature and viscosity is developed to solve the Reynolds equation to obtain different bearing performance. This paper mainly discusses the influence of the water supply pressure, rotating speed, and load carrying capacity on the power loss, friction coefficient and temperature. The results presented in this study are expected to be useful for the design of water-lubricated hybrid bearing used to support high-speed spindles.

Abstract: In addition to the high cost and long period, the traditional design of the drawing process depends too much on empirical formulas and data. To solve this problem, the paper proposes an ideal design process of the drawing process, which improves the traditional design process bases on CAE and applies FEM software Dynaform. The paper takes a drawing cylinder as an example, which needed 4-stage drawing process, could be improved into 3-stage by the simulation analysis of CAE, as a result , which can reduce the cost and improve the production efficiency.

Abstract: ELID grinding technology applied to difficult-to-machine materials’ precision and ultra-precision processing has obtained good results. Based on the existing experimental results of ELID grinding, according to the structure characteristics of the existing grinding machine, we designed and developed a special ELID grinding machine in order to greatly improve the machining precision and automation degree of the existing grinding machine and achieve precision and ultra-precision processing of difficult-to-machine materials.