Advanced Materials Research Vol. 1014

Abstract: By controlling the cooling, mean temperature adjustment and isothermal cooling process, bainite and martensite can be produced in the surface and the core of the ductile iron gear using the 75°C hot water as the quenching medium. Since it has a high hardness value in the point and the pitch circle, a low hardness value in the root and the core, this ductile iron can be applied to the actual production of the gear. The gear surface organization will be affected by quenching cooling time. The appearance of the temper phenomenon can result in the decrease of hardness value in the surface of the gear when the cooling time is short..However, the content of the lower bainite can be increased by extending the cooling time properly in the surface of the gear. The influence of the quenching cooling time on the core organization of the gear is small.

Abstract: Puguang gas field is the first deeply buried formation and high-sulfur natural gas field on developing. Due to the special composition of natural gas, the deliverability evaluation has a lot of problems. So it is very difficult to conduct a deliverability evaluation with the pressure of well bottom. In this study, an equation of wellhead deliverability is established by testing data. And it is evaluated through the wellhead open flow potential and absolutely open flow potential which is determined by another deliverability equation from well testing data. Results show that there exists a good linear correlation between wellhead open flow potential and absolutely open flow potential in each well of Puguang gas field. In addition, through applying this correlation, absolutely open flow potential can be calculated through wellhead deliverability equation, which provides a new method to study deliverability.

Abstract: This study is based on the graduation design for undergraduate course. In the paper, finite element analysis software ANSYS had been used to create the finite element model of a cannon barrel. On this basis, the vibration modal analysis of the barrel was conducted. Through the model analysis, the natural frequency and modal shape of the cannon barrel was obtained. The situations of stiffness strength and elasticity deformation about each part of the barrel were got by analysis of the modal shape. By this way, we can verify the rationality of the barrel design .Also it can provide improvements of the weak place of the structure for people to improve the stiffness and shooting precision of the gun, in order to make the dynamics characteristics of the gun more reasonable.

Abstract: YI-SHU basin is one of the key blocks in Daqing oil field exploration. After several years exploration, drilling technology and the research on formation has obtained certain achievements, but the core recovery still is not high enough since there are a large section of coal and fracture zone in reservoir, it restricted the further exploration work in this area seriously. In this article, through the various research and field practice, put forward a coring method in the fracture formation, we have got good results in practical application.

Abstract: One common and prominent reason for the tube explosion issue of pipe network is the water hammer. Because the pressure levels caused by water hammer are far exceeding the pressure range of the pipe limit. Since a great loss has been caused by water hammer damage, an important influence factor (shape of pipe) on the phenomena associated with water hammer have been performed by using the platform of numerical simulation software CFX. Analysis of the results show that the vortex and reflux phenomena appear in elbow pipe, different shape of pipe will lead to various flow regime. The pressure caused by shape is slight and can be negligible compared to the normal pressure. But it does has influence on period, 90-degree elbow will reduce 0.01s in period.

Abstract: Takeoff is important to a variety of difficult movements for sports aerobics. The paper analyzes the kinematic mechanics of takeoff in pre-jumping for the sport. It first discusses the importance of takeoff in sports aerobics, and finds that the mechanics theory can be utilized to analyze the forces produced in the process of takeoff. Then, the dynamics analysis of takeoff in pre-jumping is completed to reveal the change of the vertical force and expound the sports process from the aspect of mechanics. Subsequently, the body for the athlete is simplified a two-light-pole mechanical model. On the basis of this, the mechanics analysis of vertical force in pre-jumping is done to find the influencing factors for vertical force. The results show that the vertical force produced by the takeoff in pre-jumping suffers from the factors of the weight, length of leg, bending angle of knee, and angular speed of leg rotation, etc.

Abstract: Using biomechanics theory to reveal the reaction force of ground of support leg in instep shot in different heights in soccer players. Twelve healthy male college students voluntarily participated in this study. After testing each participant by Kistler force plate and then analyze the collected data, the present study draws the following findings that (1) The reaction force of ground on support leg was independent of the ball velocity,(2) The principal function of support leg was in charge of fixing support, maintaining balance for optimal kicking ball of kicking leg.

Abstract: The paper presents results of investigation of a flow over unguided artillery projectile in order to understand variation of flow parameters past a 155 mm artillery projectile M107 and the performance of the computational code. Furthermore; static aerodynamic coefficients were calculated. The flow around projectile was solved as 3-D unsteady compressible flow.

Abstract: Nonlinear aeroelastic characteristics of a rudder with a hydraulic booster are investigated, including the structural nonlinearity and dynamics of the hydraulic booster. The component mode substitution method is used to establish the nonlinear governing equations based on the fundamental dynamic equations of the hydraulic booster and rocker arm. Simulations are carried out when the control command is not zero and further analysis is conducted when the freeplay angle is changed. The results show that the effects of the actuator and the structural nonlinearity have a significant influence on the flutter characteristics. In the nonlinear condition, the phase and frequency of the control command have both an influence on the flutter characteristics.

Abstract: The implementation and validation of a numerical model of the confined Composition B initiated by a metal jet has been studied by AUTODYN-2D. Two different tube thicknesses were used representing strong and weak confinement initiating system. In another contrast, various materials such as Nylon, St45 and Tungsten alloy were adopted to investigate the influence of tube yield stress on the confined explosives initiation behaviour. The results show that, in both cases, the confined explosive is always more likely to be initiated than bare explosive, and the explosive initiation probability increases with the tube thickness and yield stress. The run to detonation generally increases with the increasing lateral confining strength, but decreasing jet tip velocity.