Applied Mechanics and Materials Vols. 602-605

Abstract: This paper specifically addresses the effect of changing the constant temperature region of the sintering temperature curve in manufacturing nickel powder capillary structure (wick) on the performance of a flat loop heat pipe (FLHP). The sintering temperature curve is composed of three regions: a region of increasing temperature, a region of constant temperature, and a region of decreasing temperature, with the sintering time and temperature in the region of constant temperature having significant effect on the permeability of the wick. In this study, for wick manufacturing the temperatures in this region tested range from 550°C to 650°C and the time from 30 minutes to 60 minutes. The properties and internal parameters of the wick are measured, and the wick is placed into FLHP for performance testing. Experimental results show that at sintering temperature of 550°C and lasting about 45 minutes, maximum heat load is 200W, minimum thermal resistance is 0.32°C/W, permeability is , porosity is 66%, effective porosity is 3.8and heat flux is around 21W/cm²; related literatures have only reported maximum heat load increase of 25%.

Abstract: We establish the entity model of groove beams in Midas FEA. Then we compare and analysis the shear lag effect of prestressed reinforcement caused in different locations. It can provide some suggestions for prestressed rib of groove beams. The result shows that when the prestressed steel beam is located in the middle of small beam, the effect of shear lag is maximum and the shear lag effects of prestressed in two ends are similar, Prestressed reinforcement can be arrangement refer to the results.

Abstract: The calculation methods of J - integral in ANSYS were analyzed, and through a case the implementation procedure of J - integral in ANSYS was illuminated. Then a comparison analysis was made between the stress intensity factor and J - integral, which obtained the same conclusion in classical fracture mechanics. It is demonstrated by the analysis. It is feasible to calculate J - integral of the material and it provides one extremely effective method for later calculation of fracture parameters.

Abstract: Water jet propulsion (WJP) with positive displacement pump (PD pump), in which the suction thrust of PD pump (Due to the effect of pump suction and the influence of the suction boundary layer) and the reaction thrust of water jet are used to push watercraft forward, has many advantages like high efficiency,low noise, high maneuverability, good adaptability to variable working conditions, simple transmission mechanism over traditional propulsion methods. A mathematical model is developed and the WJP theory with PD pump is analyzed. Numerical studies are carried out to study the suction thrust, reaction thrust, and propulsion efficiency of the thruster with Bernoullihyperbolic suction inlet-PD pump-Bernoulli hyperbolic nozzle. The results show that: 1) in the conditions of no cavitation in suction inlet and constant flow rate, the suction thrust is inversely proportional to the inlet diameter and reaches around 8.5% of the total thrust; 2) the reaction thrust increases with the decrease of the nozzle diameter; 3) the pump-suction coefficient v is proportional to the speed ratio μ; 4) the efficiency of WJP with PD pump is higher than with negative displacement pump under the same speed ratio. The related conclusions provide a basis for the design of high performance water propulsion unit.

Abstract: A hydraulic model is used to study the flowing process within a bottom-blowing furnace designed by a company, and the VOF model is adopted to simulate its process. The VOF method can describe the formation, growing up and separation actions in theorizing process by comparing the simulation and experimental results, and this is a foundation of using a model to research the thermal process of the bottom-blowing furnace. It is indicated that a nozzle with disperse spouts can stir a larger zone, by comparing the influence on flowing process of four nozzles with different structures. The disperse spouts are benefit to increase the stirring and reaction efficiencies, but the pressure fluctuations near the nozzle export is more obvious, and it may affect the lifespan of the nozzle.

Abstract: In order to deal well with the complexity in modeling a reducer’s production process, this paper proposes an Object-oriented Petri Net (OOPN) approach by combining object-oriented concept with Petri net theory. At first, the definitions of OOPN were given. Then, the procedure of modeling the production process with OOPN was described in detail, and the model analysis was conducted. Finally, the Flexsim software was used to simulate this model in order to find out the bottlenecks of the reducer’s process planning and some suggestions were proposed, which will lay a foundation on the optimization of its process planning.

Abstract: Only the preliminary stage of piping process can be simulated by current seepage-erosion coupled piping model. In order to enhance the simulation capability, a modified piping model is presented. Theory analysis shows that the governing equations of the modified piping model have significant advantages in practicality and solution accuracy. The solving process of the model is analyzed, with the result showing that the out-of-bounds appearance of the field variables is the major factor interrupting the solving process. Then a new solution technique called dynamic constraint is proposed, which can ensure the validity of field variables. Numerical example indicates that the new governing equations and dynamic constraint technique can enormously enhance the simulation capability of the model, and the piping process can be effectively simulated.

Abstract: To calculate the multi-angle penetration, this paper established a 3D finite element model of aluminum alloy plates and 7.62mm armor-piercing by using LS-DYNA software and the Johnson-Cook material model. The process of bullet penetrating 20mm thickness target with different angles of incidence was carried out. The impact of combinations on composite targets resistance projectile penetrating ability was analyzed. Simulation results show that,ballistic of composite targets can be between two aluminum target plate, clearly different combinations of composite targets for resistance to different angles of incidence between projectile penetrating relationship.

Abstract: This paper illustrates an application of the mass transport model, turbulent model and dynamic mesh technique to the simulation of hydrogen leakage and dispersion in the Docking Process of exhaust pipe of rocket tank. Some numerical simulations are made to investigate on the effects of the tank pressure, docking mechanism and buoyancy. The experiment results indicate that tank pressure has significant influence in horizontal direction and vertical direction of hydrogen diffusion. Besides, the effects of buoyancy are slight. In addition, direction of hydrogen flow has been changed to vertical direction mostly at 2ms as a result of the action of docking mechanism, and there are no longer dangerous concentration areas of hydrogen inside the exhaust pipe after 2ms of leakage.

Abstract: In the construction process of large-scale civil engineering and architecture, how to realize rational scheduling is a key problem need to be solved. This paper studies the construction process of the large-scale Civil Engineering decoration companies, particularly the construction with parallel multiple sets of team and multi-project. To solve the problem, the paper designs a special scheduling algorithm and carries out simulation. The scheduling algorithm shorts the duration of construction and improves enterprise efficiency.