Papers by Keyword: Orthogonal Experimental Design

Abstract: Cement asphalt mortar (CA mortar) is one of the key materials of slab ballastless track structure, and its performance directly affects the overall quality of ballastless track. The design of CA mortar mix proportion is studied by orthogonal exerimental method, and the reasonable dosage of cement, emulsified asphalt, sand and other materials is determined. The change of gas content of CA mortar is analyzed by adding air entraining agent and adjusting stirring process. The working properties, mechanical properties and freezing resistance of CA mortar are tested. The results show that the reasonable dosage of cement, emulsified asphalt and sand in CA mortar are 280~325kg/m³, 420~555kg/m³ and 360~690kg/m³, respectively. The dosage of cement has the most obvious influence on the 28d compressive strength of CA mortar, followed by emulsified asphalt. With the increase of air entraining agent content, stirring speed and stirring time, the air content in mortar will increase. Through the test of mortar's working performance, mechanical properties and frost resistance, it is shown that the appropriate amount of air entraining agent and mixing process can improve the frost resistance of CA mortar.

Abstract: This paper analyses the process of AWACS aircraft supporting fighter plane with the implementation of air blockade. On the basis of it, model fighter plane blockade combat, establish the hit probability model for solving fighter air regional blockade, do experiments by using this model, adopt orthogonal experiment for design to reduce complexity, get the key factors influencing fighter blockade combat by further combination of analytic method and simulation analysis, carry on importance analysis, and finally put forward that the first selection of combat forces configuration index are external probe and target designation information transmission delay.

Abstract: To improve the driving safety and comfort during car-following, a hierarchical car-following control system is designed. The upper-level controller determines the desired longitudinal velocity according to the vehicle state information from sensors and the minimum safety distance model based on time headway. The lower-level controller with switch logic between throttle and brake is employed for the longitudinal velocity control. The optimal PID parameters in the lower-level controller are tuned with orthogonal experimental design (OED) method, aiming at minimizing the comprehensive index about safety and comfort. Co-simulations of the car-following system are implemented in the simulation platform based on PreScan and Matlab/Simulink. The following vehicle is controlled to track a leading vehicle with a preset time-varying velocity, ensuring a safety distance between the two vehicles and improving driving comfort. The simulation results show that the car-following control system has a good performance on car-following and is suitable for intelligent vehicles.

Abstract: A comprehensive numerical method to optimize a helicopter gearbox housing vibration characteristic is presented. Thicknesses of all the shells are considered to be design variables. The variables that have more effect to the responses than others are found by sensitivity analysis through orthogonal experiment, decreasing computational cost and improving the efficiency. An adaptive response surface method is applied to maximize the first-order natural frequency with the constraint of stress and mass to reduce structural vibration and satisfy strength and mass requirements at the same time, which is a multidisciplinary optimization problem. The results show that the maximum nodal displacement frequency response is lessened 58% and the maximum element stress is 29% less than the original housing structure.

Abstract: In view of the performance of dividing the audio category is closely related to the speech feature parameters selected,a systematic and practical characteristic parameter selection method is presented,orthogonal experimental design method based on analysis of variance.This method has better characteristic [1],the construction of the experiment is simple and the result is easy to analysis,it’s also has directive function to the subsequent experiments.We first do the feture parameters and the level selection,then select amount of appropriate points with representative and typical from a large number of experimental points to construct the orthogonal table to do a analysis of variance by mathematical statistics and orthogonal principle,finding the optimal feature combination. In this pater,the experimental corpus that is voice content is divided into two categories,the kind of traffic and the legal category.Comparing the experimental results shows that the method is not only effective to do feature parameter selection in voice content classification but also has direct meaning to the subsequent experiment design and research.

Abstract: This paper simulates the process of the high-neck flange closed rolling on DEFORM-3D and optimizes the rolling process parameter by analyzing the results based on the orthogonal experimental design. For the high-neck flange, the results show that the effects on ellipticity are in the order of the mandrel feed speed, the main roll rotational speed and initial blank temperature. The former two factors show the significance while the initial blank temperature does not show that.

Abstract: In this paper, six sigma methods were used in bearing ring grinding process improvement. In the improvement, bearing outer ring roundness error was selected as the assessment index, and exsiting problems in grinding process were defined, roundness error of bearing outer ring was measured.One-way analysis of variance was applied to analyze the test results, it indicates that workpiece center height, guide wheel tilt angle and grinding wheel balance are the three main factors that affecting roundness error.According to this analysis, orthogonal experiment was designed. The results show that grinding wheel balance, guide wheel tilt angle and workpiece center height on the impact of roundness error are in descending order. On this basis, a series of measures were carried out to control these three parameters. Uitimately, the grinding process capability index is increased from 0.88 to 1.43, and the target of improvement are achieved.

Abstract: Melt blowing process can produce superfine fibers. In this process, the polymer is drawn by the high velocity hot air jets from the dual slot die. The die parameters have great effects on the fiber diameter. In this paper, the die parameters of the dual slot die in an industrial melt blowing equipment are studied using the orthogonal experimental design method. Three parameters namely the inset distance, slot width and slot angle are considered. Each parameter has three levels. Nine sizes of dual slot dies with different design parameters are numerically simulated using the established air flow field model of melt blowing process. Distributions of air velocity and air temperature of nine air jet flow fields are obtained. Effects of the three parameters are studied with range analysis and variance analysis. The results show that the inset distance and slot width have significant effects on the air flow field while effect of the slot angle is unremarkable. Finally the optimal die parameters are obtained. The results lay the theoretical foundation for further studies on the computer assisted design for the dual slot die in the melt blowing process.

Abstract: According to inputting different combination of conditions so as to produce different impacts, software testing designs a large number of test cases. If the implementation of an overall test, due to the limit of the combination of conditions, it is difficult to carry out. In order to generate high quality test cases as early as possible to improve the efficiency of software testing, it is designed a generation tool of the automatic software testing case on orthogonal experimental design. For the test data, the use of that tool design test cases. The practice shows that a small number of test cases are generated, the error detection ability is strong, and it greatly improves the efficiency of software testing.

Abstract: Effects of injection molding parameters on the residual fiber length and the mechanical properties of LFRT-PP composites, which were prepared by self-designed impregnating molding, were investigated by orthogonal experimental design method. The results showed: the length of residual glass fiber increased with the length of LFRT pellets and decreased with screw speed. The former had more remarkable impact. The mechanical properties of composites were greatly affected by the temperature of barrel. The lower temperature was benefit for obtaining the higher properties. The length of residual glass fiber was not directly corresponding with the mechanical properties. To obtain the highest mechanical properties of composites, the optimal parameter levels were: the length of pellets 10mm, the temperature of barrel 220°C, the screw speed 75 rpm and the injection pressure 80 MPa.