Volume 2 Issue 2
Authors: Vitaly I. Levin
Abstract: Existing approaches to system optimization (optimal design) under uncertainty are considered. The exact formulation of constrained optimization problem with interval uncertainty of the objective function and constraints parameters is given. The mathematical theory of intervals comparison including the precise definition of minimum and maximum ranges is stated. On the basis of this theory, the determination method is formulated and justified which allows solving problems by reducing to a two fully certain con-strained optimization problems of the same type.
Keywords: Optimization; Uncertainty; Optimization with Interval Uncertainty; Determination Method
Authors: Wen-wei GONG; Chao CHENG; Jie HE; Xue-dao SHU
Abstract: To investigate the distribution law of microstructure during stretching stage for cross wedge rolling of asymmetric shaft parts, so as to achieve a coordinated forming control of shape and quality in cross wedge rolling of asymmetric shaft parts, we employed the finite element method in this paper to simulate the process of cross wedge rolling of asymmetric shaft parts. By studying the dynamic recrystallization volume fraction and the average grain size distribution in stretching stage as well as comparing the average grain size of asymmetric rolling and symmetric rolling, we achieved the high temperature austenitic grain size distribution during stretching stage for cross wedge rolling of asymmetric shaft parts, then conducted the corresponding experimental verification. The study results have important scientific significance and engineering application value for the rolling technology innovation of cross wedge rolling shaft parts by enriching and improving the theory of cross wedge rolling of asymmetric shaft parts, reducing the production cost and improving the quality of rolled products.
Keywords: cross wedge rolling;asymmetric;microstructure