Advanced Materials Research Vols. 308-310

Abstract: Aiming at disadvantages of Genetic Algorithm (GA) and learning from the immune system theory, this paper introduces immune memory cell of immune theory, vaccine extraction and vaccination operator based on immune theory, and adaptive probability crossover and mutation operator to GA, to improve the optimization ability and search efficiency of GA, and proposes Adaptive Immune Vaccine Algorithm (AIVA). Then proves the convergence of the algorithm, gives the composition mechanisms of the key operators, and verifies the role of each operator. Finally, four test functions have been optimized using GA, AIGA and AIVA. The experimental results show that AIVA effectively overcomes the GA Defects, greatly prevents the degradation of population, and has perfect convergence stability and excellent global optimization capability.

Abstract: Based the defects of global optimal model falling into local optimum easily and local model with slow convergence speed during traditional PSO algorithm solving a complex high-dimensional and multi-peak function, a two sub-swarms particle optimization algorithm is proposed. All particles are divided into two equivalent parts. One part particles adopts global evolution model, while the other part uses local evolution model. If the global optimal fitness of the whole population stagnates for some iteration, a golden rule is introduced into local evolution model. This strategy can substitute the partial perfect particles of local evolution for the equivalent worse particles of global evolution model. So, some particles with advantage are joined into the whole population to make the algorithm keep active all the time. Compared with classic PSO and PSO-GL(A dynamic global and local combined particle swarm optimization algorithm, PSO-GL), the results show that the proposed PSO in this paper can get more effective performance over the other two algorithm in the simulation experiment for four benchmark testing function.

Abstract: Currently, Ball Mill is most used coal grinding equipment of pulverizing system of thermal power plant in China. Because of this system is multivariable, strong-coupling and serious time-delay, and it also has nonlinear, time-varying and distributed parameter characteristics. It is naturally difficult to be effective for such kind system to use PID regulation law and design multi-variable system by single-loop. So try more intelligent control for this kind system. Immune Control has fast response and robustness, especially; the Two-cell Immune Control has integration and memory characteristics, and improve the system to better control effect. It is particularly suitable for solving practical engineering application problems with robustness, adaptability and requirements of dynamic performance. So this paper use Two-cell Immune Control for the Ball Mill Control System, and make a large number of simulation experiments about rated parameter, non-rated parameter and adding disturbance situation, it has made a good dynamic and static performance under various conditions. These results confirm the validity of the design of Ball Mill Control System base on Two-cell Immune Controller.

Abstract: Abstract：The power system simulation model is established aimed at the hybrid electric bus. Optimal calculation model with restrictions is deducted at the target of minimizing equivalent fuel consumption. The optimal torque distribution of Chinese typical city cycle is solved with optimal theory. The simulation results reveal that the optimal control strategy can improve fuel economy and power system efficiency significantly.

Abstract: This paper presents an integrated design technique to carry out simultaneous topology and sizing optimization of a two-dimensional truss structure. An optimization problem is set to find a structural layout and elements’ cross-sectional areas of a 2D truss such that objective functions including mass, compliance, and buckling factor are optimized. Design constraints consist of stress, buckling, and compliance. The concept of an adaptive ground elements approach and the encoding/decoding process are detailed. The multiobjective version of population-based incremental learning (PBIL) is employed to solve the design problem. The results reveal that the proposed design strategy is efficient and can be an effective engineering design tool.

Abstract: In this work, performance enhancement of a multiobjective evolutionary algorithm (MOEA) by integrating a surrogate model to the design process is presented. The MOEA used in this work is multiobjective population-based incremental learning (PBIL). The bi-objective design problem of a pin-fin heat sink (PFHS) is posed to minimize junction temperature and fan pumping power while meeting design constraints. A Kriging (KRG) model is used for improving the performance of PBIL. The training points for constructing a surrogate KRG model are sampled by means of a Latin hypercube sampling (LHS) technique. It is shown that hybridization of PBIL and KRG can enhance the search performance of PBIL.

Abstract: Thermoelectric coolers and generators are often used as reliable energy converters in a variety of applications. For design considerations, it is investable to establish an effective methodology to simulate the TEC/TEG performance within the cooling/generating system constraints. For this purpose, firstly, three approaches are established to find the internal parameters of a given thermoelectric module. For these procedures, simulated pumping powers are in the sequence of method III < method II < method I for each temperature difference conditions. Hence, the good estimation way of the simulated data is by averaging the results of these three methods. Finally, the design approach is implemented to freezing chuck designs. Temperature distributions on the top surface of chuck are measured by experiments for comparisons. It shows that the established TEC model is applicable to obtain accuracy temperature fields for the purpose of freezing chuck design.

Abstract: Surface roughness is an important parameter to evaluate the quality of high-speed machining (HSM). This paper establishes a mechanical model based on the molecular-mechanical theory of friction to study factors that influence the surface roughness in HSM. The relationship between flow stress and the remnant height on the machined surface is obtained. The HSM process of AISI-1045 steel is simulated by using finite element method (FEM) based on DEFORM-2D and the flow stress is obtained. The surface roughness of workpiece machined by HSM is calculated based on the value of flow stress and the mechanical model. The result shows that the surface roughness of workpiece in HSM is acceptable, and the mechanical model supplies a method to study the surface roughness in HSM.

Abstract: In this work, to reduce the drag of a van body truck, an aerodynamic device is fixing on the aft-body with different angle of declination and shape of the wing. The effects of reducing drag are studied by the methods of Numerical Simulation. And then the mechanism is discussed. The paper selects four rear add-on devices with different obliquity by 5deg, 10deg, 15deg and 20deg. And the shape of the wing is defined as straight line and curve, respectively. Seen from the results of numerical simulation, the rear add-on device can reduce the drag effectively. When the declination angle is 15deg, the effect is the best and the drag of the truck model is reduced by 8.9%. Furthermore, when the add-on plate is changed from contouring with straight line into Witozinsky curve in the same declination angle, the drag can reduce about another 3%. With the optimum declination angle and wing shape, the drag of the truck model is reduced 11.98%.

Abstract: Combined with the new development of protecting pile of foundation pits in Ningbo soft soil area. On the premise of summarizing the present calculation of supporting structure, contrasting borehole case-in-place pile of circular cross section with rectangular borehole case-in-place pile and soldier piles according to the theory of equal-rigidity calculation and the analysis of reinforcing quantity calculation. we figure out that the rectangular borehole case-in-place pile have an potential in saving materials.