Optimal design of structural parameters for shield cutterhead based on fuzzy mathematics and multi-objective genetic algorithm

In order to improve the strength and stiffness of shield cutterhead, the method of fuzzy mathematics theory in combination with the finite element analysis is adopted. An optimal design model of structural parameters for shield cutterhead is formulated,based on the complex engineering technical requirements. In the model, as the objective function of the model is a composite function of the strength and stiffness, the response surface method is applied to formulate the approximate function of objective function in order to reduce the solution scale of optimal problem. A multi-objective genetic algorithm is used to solve the cutterhead structure design problem and the change rule of the stress-strain with various structural parameters as well as their optimal values were researched under specific geological conditions. The results show that compared with original cutterhead structure scheme, the obtained optimal scheme of the cutterhead structure can greatly improve the strength and stiffness of the cutterhead, which can be seen from the reduction of its maximum equivalent stress by 21.2%, that of its maximum deformation by 0.75%, and that of its mass by 1.04%.     

燃烧法制备氧化物纳米材料的研究进展

燃烧法是制备氧化物纳米材料的一种新方法，其中，气相燃烧法、燃烧火焰—化学气相凝聚法已经实现了工业化生产；而一些新的工艺方法，如低温燃烧合成法、喷雾燃烧法、电控火焰合成法在刺备纳米材料上也各有优缺点；燃烧法与其他技术的结合也在研究开发阶段。详细阐述了燃烧法的最新研究进展。