Constructing metamodel with global high-fidelity in design space is significant in engineering design. In this paper, a double-stage metamodel （DSM） which integrates advantages of both interpolation metamodel and re...
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Constructing metamodel with global high-fidelity in design space is significant in engineering design. In this paper, a double-stage metamodel （DSM） which integrates advantages of both interpolation metamodel and regression metamodel is constructed. It takes regression model as the first stage to fit overall distribution of the original model, and then interpolation model of regression model approximation error is used as the second stage to improve accuracy. Under the same conditions and with the same samples, DSM expresses higher fidelity and represents physical characteristics of original model better. Besides, in order to validate DSM characteristics, three examples including Ackley function, airfoil aerodynamic analysis and wing aerodynamic analysis are investigated, In the end, airfoil and wing aerodynamic design optimizations using genetic algorithm are presented to verify the engineering applicability of DSM.
Large-angle attitude maneuver is common during the mission of spacecrafts, such as aligning to star to calibrate navigation system. Published works on attitude tracking always focus on optimizing the time and fuel cos...
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The paper bring forward a design of multilayer structure which has a high reflectivity for 1.82μm laser beam and a high absorptivity for 1.48μm laser beam. The experiment reveal that the absorptivity of the film rea...
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Two kinds of magnetic gauges, including electromagnetic particle velocity (EMV) gauge and a combined gauge composed of EMV gauge and electromagnetic (EM) stress gauge, are introduced to investigate the dynamic damage ...
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Large-angle attitude maneuver is common during the mission of spacecrafts, such as aligning to star to calibrate navigation system. Published works on attitude tracking always focus on optimizing the time and fuel cos...
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Large-angle attitude maneuver is common during the mission of spacecrafts, such as aligning to star to calibrate navigation system. Published works on attitude tracking always focus on optimizing the time and fuel cost, neglecting the smoothness requirement and angular speed limitations. In this paper, a nonlinear control algorithm is prompted for smooth transition in large-angle attitude maneuver. A nonlinear filter is added to the attitude feedback control loop, to carry out angular speed control in large-angle maneuvers. Simulation results demonstrated the effectiveness and reliability of proposed approach.
Based on the thermodynamic theory, the dependence of sublimation energy of metal on temperature and pressure is discussed, and the results indicate that the sublimation energy decreases linearly with the increase of t...
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Based on the thermodynamic theory, the dependence of sublimation energy of metal on temperature and pressure is discussed, and the results indicate that the sublimation energy decreases linearly with the increase of temperature and pressure. Combined with this result, the blow-off impulse of aluminum induced by pulsed X-ray is simulated by smoothed particle hydrodynamics (SPH) method. The numerical results show that, while the change of sublimation energy with temperature and pressure is considered, the blow-off impulse of aluminum is larger than the case that the sublimation energy is assumed to be a constant.
In the ground-based FSR, the strong ground reflected signal seriously cancel the useful signal, as a result the estimation methods of the target images in current SISAR imaging technology are no longer applicable. The...
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In the ground-based FSR, the strong ground reflected signal seriously cancel the useful signal, as a result the estimation methods of the target images in current SISAR imaging technology are no longer applicable. The height difference of the target can't be estimated from the amplitude of complex profile function (CPF). In this paper, firstly, the multipath interference on the forward scatter (FS) signal model and imaging results of the moving target are analyzed by the two ray path model. Then, the estimation methods of the target profile image under multipath interference condition are presented. As a result, the accurate target images that cannot be achieved by using the current imaging algorithm can be extracted using the modified imaging algorithm. Finally, the effectiveness of the estimation methods is validated by the simulations.
An investigation was made into the argon plasma jet that expanded in a low-pressure vacuum chamber. The spatial distributions of the parameters of the plasma jet with different supplied powers were measured using a te...
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An investigation was made into the argon plasma jet that expanded in a low-pressure vacuum chamber. The spatial distributions of the parameters of the plasma jet with different supplied powers were measured using a ten-channel Langmuir probe array. The chemical species in the plasma jet were identified by emission spectroscopy. The electron excitation temperatures at two positions, 10 cm and 50 cm downstream from the nozzle exit were calculated, respectively, by the Boltzmann plot method.
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