Advanced Materials Research Vol. 681

Abstract: In order to ensure safety and efficiency in high pressure waterjet clearing HTPB propellant, the lower limit of outlet pressure was determined as 60MPa according to the compressive strength of HTPB propellant and the upper limit of outlet pressure was determined as 100MPa through ignition mode analysis and temperature rise experiment. Based on the corresponding empirical formula, the optimal target distance under different outlet pressure was calculated. Through the small size propellant clearing experiments, the main process parameters in high pressure waterjet clearing HTPB propellant were optimized. The optimal processing conditions of safe clearing are 100MPa for outlet pressure, 30mm for target distance, 0.25mm for nozzle diameter, 15minutes for single clearing time and thus the corresponding mass loss and clearing efficiency are 263.3g and 17.55g/min respectively.

Abstract: To find some rules keeping good lubrication condition for plane port pair in high-performance axial piston pump or motor, especially in the very severe applications, a new test rig was built up to simulate the operational principle of port pair, and to form the lubricating oil film for representative parameter acquisition. This rig is principally characterized by supply pressure up to 30 MPa, accurate control of oil film thickness by separate oil circuit design and electrohydraulic feedback control. The tested oil film working properties was analyzed by comparison with theoretical or simulation references. Experiments show that film balance time and thickness are two key parameters for describing oil film properties, and that working condition factors such as supply pressure, lubricating fluid temperature also notably affects the film thickness and its configuration, but they don’t show equivalent action. Lubrication effects can be valued by the tested frictional torque change of port pair.

Abstract: The clutter distribution of airborne radar with non-sidelooking uniform linear array antennas varies with ranges and samples in different range gates are not independent identically distributed vectors, so that the statistical STAP methods degrade greatly. In this paper, an improved clutter range dependence compensation method for airborne radar with uniform linear array is proposed. This method involves in a preprocessing with ADC method to align the mainlobe of clutter spectrum in different range gates and subsequently clutter suppression in other azimuths with EDBU technology. Simulation results show the proposed method can reduce the clutter spectrum dispersion significantly and outperform conventional local compensation methods.

Abstract: Shaft angular acceleration is one of the most important parameter of rotary machines, the designation and implementation of a new angular acceleration measurement system is proposed in this paper. First, the speed signal is acquired through grating and infrared photocell, then interpolation speed signal with high-frequency pulses, so as to convert speed signals to pulses, last, angular acceleration is received by processing these pulses. This measurement system combined with FPGA and SCM, the function of FPGA are generating pulses、interpolating speed signal and counting the number of pulses, the result of count is processed by SCM. The high accuracy of measurement system is verified accord to the test.and the causes of errors are received by theoretical analysis.

Abstract: This paper aims at studying a method to identify the cutter runout parameters for end milling. An analytical cutting force model for end milling is proposed to predict cutting force. The cutting force is separated into a nominal component independent of the cutter runout and a perturbation component induced by the cutter runout. Using the cutting force acting on the and directions to calculate the difference between the cutting radius of the adjacent tooth. Then runout parameters are obtained after a series of data processing. The simulation and the experimented results are made to validate the presented methods.

Abstract: The numerical simulation of the ironing process of deep cup shaped part was conducted by finite element software Deform 3D. The influences of interface friction and deformation velocity on the forming load and blank damage were studied in this paper. The simulation results showed that the forming load and damage increased obviously with the increase of the friction between the blank and cavity die. The blank damage increased and the forming load decreased with the increase of deformation velocity. These conclusions provide a reliable theoretical basis for the optimization of the ironing process of deep cup shaped part.

Abstract: The accelerate driven system has an important role in sub-critical reactor. With the good physical property of high specific heat, low vapor pressure, low thermal decomposition rate and so on, the glycerol, hydrogenated terphenyls and water of low pressure are widely used in the accelerate driven sub-critical reactor as the secondary coolant. Compare the three coolant by the aspect of heat economy and engineering safety, we conclude that, compared with the glycerol and the hydrogenated terphenyls, water of low pressure has the best heat economy, at the same time it has the lowest pressure drop and the highest coefficient of heat transfer in the heat exchange tube. Therefore, choose water in low pressure as the secondary coolant in sub-critical reactor can decrease the heat exchange area to a large extent, together with the advantage of economy and safe.

Abstract: In the research of the automobile front dash, the key of design is that acoustic need should be satisfied while losing the weight. In this paper, a structure-sound field coupling model of car body space is built. To fulfill the request, the dash panel is divided into several parts, and the sensitivity of thickness of each parts to the sound at the position of driver’s and co-pilot’s ears is calculated. Based on the sensitivity, the driver’s and the co-pilot’s parotic sound pressure is optimized while reducing the weight of front dash. The result proves that lightweight design is successful, which gives the reference to the design of the car body panels.

Abstract: Based on the basic structure in the practical installation condition, the static model of the instrument panel (IP) beam assembly is developed. To reduce the weight, Mg is substituted for steel as the material of the structure. The finite element software is used to evaluate the constraint modal performance, rigidness and strength withstanding the specific load. After the comparison of model analysis with different materials, the Mg-based IP beam assembly is optimized to achieve the performance the steel-based one has. The process offers the reference to the lightweight design of Mg-based IP beam assembly.

Abstract: In order to investigate the calculation ability of meshless method and calculation precision for lift and drag force coefficient based on N-S equations with S-A turbulence model and Euler equations, numerical simulation of flow field around the DLR-F4 wing-body, supplied by the AIAA Drag Prediction Workshop, is employed using meshless method. Furthermore, the calculated results are compared with experiment results and Waller’s simulation results achieved by MGAERO software. It’s found that the present simulation results without consideration of fluid viscosity don’t agree well with Waller’s and experimental results. The present simulation results with consideration of fluid viscosity were found to be in good agreement with experimental results. These results indicate that meshless method coupled with S-A turbulence model could predict the natural flow characteristic around the DLR-F4 wing-body configuration well.