There are currently three different game strategies originated in economics: (1) Cooperative games (Pareto front), (2) Competitive games (Nash game) and (3) Hierarchical games (Stackelberg game). Each game achieves different equilibria with different performance, and their players play different roles in the games. Here, we introduced game concept into aerodynamic design, and combined it with adjoint method to solve multi-criteria aerodynamic optimization problems. The performance distinction of the equilibria of these three game strategies was investigated by numerical experiments. We computed Pareto front, Nash and Stackelberg equilibria of the same optimization problem with two conflicting and hierarchical targets under different parameterizations by using the deterministic optimization method. The numerical results show clearly that all the equilibria solutions are inferior to the Pareto front. Non-dominated Pareto front solutions are obtained, however the CPU cost to capture a set of solutions makes the Pareto front an expensive tool to the designer.The project supported by the National Natural Science Foundation of China (10372040) and Scientific Research Foundation (SRF) for Returned Oversea’s Chinese Scholars (ROCS) (2003-091). The English text was polished by Yunming Chen. 相似文献
To eliminate oscillation and overbounding of finite element solutions of classical heat conduction equation, the author and Xiao have put forward two new concepts of monotonies and have derived and proved several criteria. This idea is borrowed here to deal with generalized heat conduction equation and finite element criteria for eliminating oscillation and overbounding are also presented. Some new and useful conclusions are drawn. 相似文献
A new compatible finite element method for strain gradient theories is presented. In the new finite element method, pure displacement derivatives are taken as the fundamental variables. The new numerical method is successfully used to analyze the simple strain gradient problems – the fundamental fracture problems. Through comparing the numerical solutions with the existed exact solutions, the effectiveness of the new finite element method is tested and confirmed. Additionally, an application of the Zienkiewicz–Taylor C1 finite element method to the strain gradient problem is discussed. By using the new finite element method, plane-strain mode I and mode II crack tip fields are calculated based on a constitutive law which is a simple generalization of the conventional J2 deformation plasticity theory to include strain gradient effects. Three new constitutive parameters enter to characterize the scale over which strain gradient effects become important. During the analysis the general compressible version of Fleck–Hutchinson strain gradient plasticity is adopted. Crack tip solutions, the traction distributions along the plane ahead of the crack tip are calculated. The solutions display the considerable elevation of traction within the zone near the crack tip. 相似文献
Aiming at the problem of unstable buffering process of electromagnetic buffer (EMB) under intensive impact load, a three-segment electromagnetic buffer is proposed. The inner tube and air-gap of EMB are divided into three segments. The finite element analysis and impact test results show that the resultant resistance force (RRF) curve has two hump-shaped peaks, which is the reason for the unstable buffering process. In order to stabilize the buffering process, a multi-objective optimization design method of EMB based on Nash game theory is proposed. Firstly, the optimization model is established by taking the two peaks of the RRF curve and the maximum buffer displacement as the optimization objectives. Secondly, the multi-objective optimization model is transformed into a game model by sensitivity analysis and fuzzy clustering. Then, a Nash equilibrium solution strategy of EMB Nash game model based on symmetric elitist information exchange is proposed, which integrates gene expression programming (GEP) surrogate model and genetic algorithm (GA) as an optimization solver. Finally, the Nash equilibrium of the game model is obtained. The results show that the smoothness of the RRF curve has been significantly improved, which proves the effectiveness of the game strategy.
An inverse analysis of estimating temperature-dependent heat capacity for a heat conduction problem is presented. The heat
capacities are assumed to be temperature-dependent of first and second-order polynomial functions, respectively. A fitness
function is minimized by implementing the particle swarm optimization algorithm for the inverse analysis. Computation results
are provided to demonstrate the performance of the particle swarm optimization algorithm. The comparison to the modified genetic
algorithm is also included. 相似文献