Applied Mechanics and Materials Vol. 483

Abstract: A dynamic finite element model of a coupled gear-rotor-bearing-housing gear system is developed by combining the gearbox transmission model with the housing structure model of spiral bevel gearbox used in ship lift synchronization system with taking stiffness excitation, error exaction and meshing impact exaction as the dynamic excitation. The intrinsic modes and vibration response are calculated, and then the modal frequency, mode shape, vibration displacement, velocity and acceleration of the gearbox are obtained to achieve the goal of prediction on vibration severity. In fact, the proposed approach not only provides a more comprehensive understanding of spiral bevel gearbox, but also can serve as the basis for vibration control of gear system used in ship lift synchronization system.

Abstract: In this research, the acoustic-refrigeration thermoacoustic conversion system numerical model was constructed, the combined influences of structural and positional parameters of stack on the temperature difference at two ends (DT) and the coefficient of performance (COP) were analyzed. Besides, the acoustic-refrigeration thermoacoustic conversion test system was built up. Finally, experiments were performed to testify the calculation results of the conversion system. The results showed that within the common ranges of the parameters values, the porosity of stack affected the COP slightly while the temperature difference seriously, the temperature difference at the two ends of stack increased with the increase of the porosity of stack; for stacks which have the same porosity and gaps between each parallel plate, two values for the center position of stack were exist of which one could make the temperature difference get to the best value, the other one made the COP achieve the maximum value; when the porosity and the center position of stack remained constant, the temperature difference increased first and decreased afterwards with the increase of the gaps height between each parallel plate. In the selected model, the temperature difference at the ends of stack got an ideal value when 2y₀=0.45 mm (the gaps height between each parallel plate was nearly about 2.4 times than thermal penetration depth). The results provided the theoretical basis and experimental evidences for improving the performance of acoustic-refrigeration thermoacoustic conversion system.

Abstract: The equivalent thermal conductivity of superalloy honeycomb core structures have been studied by experimental method. Test results show that the decrease in honeycomb core height and the increase in honeycomb core diameter would lead to a lower equivalent thermal conductivity for superalloy honeycomb cores. Filling adiabatic materials such as ZrO₂ fibers and SiO₂ aerogels into core cells would significantly reduce the equivalent thermal conductivity of honeycomb cores with a minor penalty in structure weight.

Abstract: A parametric FEM analysis method is introduced for the design of disc brakes. The basic process of parametric FEM modeling is summarized, the FEM model of disc brakes is established. Finally, the parametric FEM strength and stiffness analysis are conducted for the typical disc brake assembly.

Abstract: The cracking problem of the engine exhaust manifold is studied in this paper. The temperature field and thermal stress are calculated. Meanwhile the modal under the thermal stress are analyzed. As a result, thermal load and thermal stress has little effect on the engine exhaust manifold. However, the result of modal analysis indicates that the structure vibration is excessive which may cause the structural cracking.

Abstract: Air-cushion vehicles (ACVs) provide a solution to transportation on soft terrain, whereas they also bring a new problem of excessive energy consumption to be solved. The prerequisite for energy consumption optimization is its modelling and simplification with respect to vehicle independent operating parameters. In a scenario of steady-state longitudinal drive condition, by employing slip ratio and load distribution ratio as independent parameters, dependent parameters and energy consumption are inferred and finally expressed as functions of the independent parameters. The method and result can be taken reference by studies of energy consumption modelling for air-cushion vehicles in different structures and also extensively for common electric vehicles.

Abstract: With the rapid development of urbanization,the building energy use increases rapidly, in order to guarantee the sustainable development of our country road, energy saving, low carbon, emission reduction work has become an urgent issue.Building energy consumption database is an important part of the construction of energy-saving work, In this paper, the aim is to establish the large-scale public building energy consumption database system in northeast cold area of , mainly introduced the database development tools, the choice of object oriented programming method , the system design process,treating the ground source heat pump system as the research object, this paper have had research and analysis on applicability of ground source heat pump system and established the evaluation system.

Abstract: Existing hydraulic feedback pump from the structure type can be divided into three kinds, big on the small,small on the big,big up and down. This paper focuses on the inner-flow field of three structural pumps about oil import and export of analyzing and comparing the velocity field and pressure field, chooses more suitable for hollow sucker rod oil production of hydraulic feedback pump.

Abstract: The efficiency analysis of wave energy collection and conversion is crucial for utility of wave energy of inverse pendulum. In the paper, we build the hydrodynamic model of interaction between pendulum and wave in wave energy converter of inverse pendulum. On the basis of this typical model, we choose the actual wave condition of some sea area in the east of China as the background, research the hydrodynamic property of pendulum by numerical simulation with fluent software, get the relation curve of between the rotation angle of pendulum and moment of wave force with time, and acquire energy conversion model from wave energy to mechanical energy in wave energy converter of inverse pendulum. It makes the beneficial exploration for optimal design of wave energy converter of inverse pendulum.

Abstract: This paper presents a feasible approach for modeling and locating of assembly\disassembly tools in the virtual scene: First, a novel point-vector model for tool is presented by means of abstracting the locating constraints of tools; Then, the mapping relationship for locating constraints between tools and parts is detailed; Finally, the best matching constraints algorithm is proposed on basis of point-vector model, which can calculate the locating constraints to the triangle model of part in real time. The proposed method has been integrated in the virtual assembly system to solve practical assembly problems.