Advanced Materials Research Vols. 228-229

Abstract: Involute helical gears mesh based on the intersections of involute helicoids. However, spiral involutes on the tooth surface do not participate in meshing directly. A new type of gear drive, the spiral involute gear drive is proposed that works on contact of spiral involutes. The generation of tooth profile is introduced in detail. Through relative-stagnation method spiral involutes prove to have conjugation characteristics. To testify whether the transmission ratio of cylindrical spiral involute gears is constant, simulation is implemented in commercial codes ADAMS based on solid models of a pair of spiral involute gears. The computed results show that this novel gear drive can achieve a constant transmission ratio. Due to transmission with uniform velocity, cylindrical spiral involute gears can be used in transmission between intersecting axes, so that generating milling and generating grinding can be achieved.

Abstract: Plasma carburizing of AISI 316L austenitic stainless steel was carried out at low temperature to improve the surface hardness without degradation of its corrosion resistance. And the post-treatment, namely electrochemical surface brightening process was carried out to clear away a layer of thin black film on the plasma carburized samples and improve the surface quality of the hardened stainless steel. The surface appearance, roughness, microstructures, microhardness and corrosion resistance of the samples before and after brightening were analyzed and compared. Experimental results of plasma carburizing at low temperature showed that high-quality hardened layers can be produced at the appropriate process parameters.The electrochemical brightening process can be used as a post-treatment to restore the original color and further improve the corrosion resisitance of the plasma carburized stainless steel.

Abstract: This paper established finite element models of adult head based on GB/T 24550-2009 and hood of a car. When the finite element model of the adult headform impactor was established, tests were carried out to prove that the impactor was valid. Then experiments were carried out at adult head test area of the hood. The results show that some areas of the hood are too hard where the hood hinges are installed. It is very bad for pedestrian head to hit those areas in accident. In order to protect pedestrian head efficiently, this paper proposed a new kind of hood hinge, called buffer-type hinge. Comparison tests were carried out. The buffer-type hinge is proved to be more effective to protect pedestrian head in traffic accident.

Abstract: The clearances in pitch mechanism of gun, such as barrel-guide, have important influence on firing accuracy. Since the sliding pair is the typical characteristics of slide plate of gun barrel and guide’s contact, the clearance can be simplified to the cantilever beam with a small gap. Dynamics models which influence the factors on cantilever clearance are established by cantilever clearance sets. The influence of clearance and the flexibility of clearance are simulated and vilified by numerical analysis. The results of the experiments are that the response signals in time domain reflect clearance size: in the same intensity under sinusoidal excitation, with enlargement of the clearance, the peak value of gun barrel time-domain signal is smaller. The current work can be referred by the gun firing accuracy design.

Abstract: Ti ions were implanted into H21 steel to improve the surface structure of oxides in H21 steel. The wear characteristics of the implanted steel was measured and compared to the performance of the un-implanted steel by a line-cutting apparatus and an optical interference microscope. The Ti concentration depth profile of the implanted steel was measured by Rutherford backscattering spectroscopy (RBS). The structure and composition of oxides were analyzed by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), respectively. The results showed that the improved wear resistance of the implanted steel was mainly due to the structure and composition changes of the surface oxides after Ti ion implantation.

Abstract: TiB2-Al2O3 composite was studied by the first principle method. Ti maintains a high positive charge and O increases more charge (absolute value) in the interface, so there is strong ionic interaction among the ions in the interface of TiB2-Al2O3 composite. There is strong covalent interaction among the atoms in the interface of the TiB2-Al2O3. There are some differences of densities of state (DOS) between TiB2- Al2O3 composite and related single phases as the interaction between of TiB2 and Al2O3 phases. The width of DOS of interface Ti 3d is obviously larger than that of inner Ti, and larger than that of TiB2 single phase, which shows that the interaction among atoms in the interface is stronger than that in the center.

Abstract: The process of use catalyst or functional material that contains iron ion to weaken -O-H-X- (X=O, N and S) bond of the thick oil to reduce viscidity or crack, in aspects of the ion charge, covalent bond order, total energy and the average distance of Fe-X, is studied with density function theory and discrete variational method (DFT-DVM), one of the first principle methods. Sulfur is with positive charge, and the hydrogen bond of -O-H-S- does not form. The strength of -O-H-N- hydrogen bond is a bit larger than that of -O-H-O-. With the decrease of the distance of Fe-X (X=O, N), the charge of Fe ion increases, the charge of hydrogen ion decreases, and hydrogen bond is weakened.

Abstract: The method based on solidification mathematical model and Flemings formula was adopted to simulate electroslag remelting process. The simulation results show that the depth of the molten pool become deeper with increasing of melting speed, and when the ingot gets to the certain height, the system is in the quasi-steady state, the pool shape doesn’t change. With increasing of melting speed, secondary dendrite spacing become wider too and secondary dendrite spacing become wider gradually from the surface to center of ingot if melting speed is const. According to the simulated dendrite spacing, micro-structure of slab ingot is estimated to if meeting the demand of solidification quality, and if it can’t meeting this demand, technological conditions(melting speed)should be modified, and recalculating secondary dendrite spacing, controlling solidification structure.

Abstract: Delay-dependent stability of descriptor neutral systems with mixed delays is investigated in this paper. Based on descriptor system approach, some new delay-dependent stability and robust stability criteria are established in terms of a operator and linear matrix inequalities(LMIs). Lyapunov-Krasovskii functional and Leibniz-Newton formula are applied to find the stability results.

Abstract: To achieve sustainable development, conserve energy and reduce emission are the themes of modern society. Life Cycle Design is an important design philosophy while Modular Design is one of the modern design ways which produced in the economic development. This paper presents a more perfect Modular Design based on Life Cycle Design. This paper will be developed in three parts: the first part introduces the basic concepts of the Life Cycle Design, Modular Design and the relationship between them; the second analyses the necessity of Modular Design in all stages of the product life cycle and the matter to be attended to; and third presents the method and steps of the Modular Design based on the Life Cycle Design and takes the design of range hood as an example in order to explain it.