Applied Mechanics and Materials Vols. 300-301

Abstract: Compared with API (American Petroleum Institute) OCTG (Oil Country Tubular Goods) thread, Non-API thread OCTG has excellent sealing performance and high joint strength for greater depth, higher pressure and temperature, other more rigorous working conditions as well. This paper describes the special structures of a kind of Non-API connection in specific, which is widely used in domestic oil field and gas storage, detailed examination of this connection and recommended practice to measure its thread. So as to provide some useful reference and help for field inspection, it also focuses on the connection’s unusual measure items and points some problems in the process of thread inspection.

Abstract: Using the analytical and numerical approaches, the nonlinear dynamic behaviors in the vicinity of a compound critical point are studied for a simply supported functionally graded materials (FGMs) rectangular plate. Normal form theory, bifurcation and stability theory are used to find closed form solutions for equilibria and periodic motions. Stability conditions of these solutions are obtained explicitly and critical boundaries are also derived. Finally, numerical results are presented to confirm the analytical predictions

Abstract: Aiming at most of the aviation products are facing the problem of fatigue fracture in vibration environment, we analysis the structure of a bracket with ANSYS-Workbench, predict the life of the bracket by different ways, and compared with the testing result, then use the Fatigue damage spectrum (FDS) and Extreme Response Spectrum (ERS) to analysis expected results. The research not only ensure the accuracy of simulation analysis and life predict, but also make a dynamic supervision of product life process, promote the application of finite element simulation analysis in engineering practice.

Abstract: The key of a safety landing is the arresting hook can engage an arresting wire. Thus, research on motion law of arresting hook during landing is essential. The construction features and function of typical arresting hook installation is studied. Take into consideration the influence on collision process produced by the deck friction in order to build an actual model of arresting hook during landing. So we can use the model to study the motion law of arresting hook during landing for the sake of supplying a beneficial reference to design of arresting hook and successful engagement with an arresting wire. Simulation results show that the value of height of first hook bounce diminishes linearly with increasing values of coefficient of friction and increases linearly with increasing values of sinking speed. Therefore, we should consider the deck friction in an arresting hook collision which is available for designing a reasonable damper and must ensure the value of sinking speed in a reasonable range to satisfy the condition of engagement with arresting gear.

Abstract: Abstract. A fast and accurate equivalent circuit model for spiral inductors on lossy silicon substrate is presented and the parameters of the model are extracted without applying any fitting and optimized methods. In this model, the lateral resistance and inductance of substrate are introduced to model the eddy-current losses induced by magnetic coupling between the spiral and the substrate. FastHenry method is used to extract the inductances of spiral, substrate, and the mutual inductance between them. A numerical formulation is used to efficiently capture the proximity and skin effects in metal tracks. The proposed model is used to predict the performance of two typical spiral inductors fabricated in CMOS technology. The model shows excellent accuracy and efficiency by the comparison with measure results at the frequency from 100MHz to 10GHz.

Abstract: A simple and convenient model to analyze the composition of the syngas has been implemented. We collect thermodynamic properties data from JANAF tables and Turns’ book. By regression analysis the Gibb’s energy functions of temperature were got. Through these functions, the equilibrium constants as functions of temperature can be deduced for the related chemical reaction in gasification process. With the equilibrium constants, the model to calculate the equilibrium composition for pure carbon gasification has been established. The model was improved from considering only isothermal reaction to including reaction heat balance and then finally with fully energy balance consideration. Since the model has been implemented on general software Excel, it will be very easy for users to apply in further study. Finally, we show how precise the estimation could be by doing comparison with early study and utilize this tool to analyze the heat balance for a specific IGCC cogeneration power plant.

Abstract: The echo signal received by laser fuze was very weak when the detection range increased. In order to expand the operating range of fuze, the reception capacity of fuze for weak signal should be improved. According to the requirements of long-range laser fuze receiving system as small volume, low-power, low-noise, high-gain, the amplifying circuit of the receiving system was analyzed and designed. To improve the ability of laser fuze for detecting weak signal, the high-sensitive, low-noise, inner-gain avalanche photodiode (APD) was used as a photodetector in the system, and the low-noise preamplifier and voltage amplifying circuit was designed. The noise and frequency response of the amplifying circuit was researched and analyzed by simulation and experiment. The results show that the design is effective and feasible, which can meet the requirements of processing circuit as receiving weak signal from long-distance.

Abstract: For studying the influence of the stator ventilation structure on the thermal performance of a synchronous machine, the mathematical model of the stator three-dimensional temperature fields is set up and the corresponding equations solved. The calculated results of the stator temperature are compared between different number of the radial ventilation ducts, which provides a theory foundation for the analysis and design of the cooling system and improves the safe operation condition of large synchronous machine.

Abstract: Silent watch operation is a typical driving condition of power-split hybrid electric vehicle (PSHEV) which has advantages of both series and parallel HEVs. Because of the complicated structure and operations of PSHEV, an advanced thermal management system with effective control strategy is needed urgently. Properly-adopted heat transfer regulations under different vehicle driving conditions are the basis of TMS control strategy establishment. In this study, we begin this work from the typical vehicle operation-silent watch operation. Then, the heat transfer regulation of PSHEV under silent watch operation is researched and analyzed with the present advanced TMS. The results can provide theory and data bases for the future research of TMS control strategy for PSHEV.

Abstract: The wind tunnel measurement and numerical simulation of a 50% scaled sedan model surface pressure distribution were made in order to provide fundamental data for improving the Computational Fluid Dynamics (CFD) simulation accuracy of the aerodynamic noise related flow field around automobiles. The pressure measurement positions of the wind tunnel experiment were on the side window and the door. The wind tunnel test section speed was 30m/s at 0° yawing angle. As for the CFD simulation, the wind tunnel shape computational domain and four settings of the near wall computational mesh were made. Both the k-ω SST and the Realizable k-ε turbulence models were chosen. And three value ranges of the near wall computational mesh’s dimensionless wall distance (y₊) were realized. Compared with the experimental data, the pressure coefficient (C_P) simulation results showed good agreement with the measurement at the re-attaching region on the side window and the attaching region on the door. But the large C_P prediction errors happened in the region of the front pillar vortex, the side view mirror wake. It was also shown that the predicted C_P values were almost independent of the y⁺ value, except the comparatively larger C_P predicted errors on the side window obtained by using the k-ω SST turbulent model when the y⁺ value ranged from 4 to 7. Further unsteady CFD simulation and the exterior aerodynamic noise measurement need be carried out due to the unsteady features of the separated flows, including the front pillar vortex and the side view mirror wake.