The analytical elastoplastic rolling/sliding model for two-dimensional contact proposed by McDowell is an important tool for predicting residual stress in rolling/sliding processes. In application of the model, a prob...The analytical elastoplastic rolling/sliding model for two-dimensional contact proposed by McDowell is an important tool for predicting residual stress in rolling/sliding processes. In application of the model, a problem of low predicting precision near the surface layer of the component is found. According to the volume- constancy of plastic deformation, an improved algorithm for McDowell＇s model is proposed in order to improve its predicting accuracy of the surface residual stress. In the algorithm, a relationship between three normal stresses perpendicular to each other at any point within the component is derived, and the relationship is applied to McDowell＇s model. Meanwhile, an unnecessary hypothesis proposed by McDowell can be eliminated to make the model more reasonable. The simulation results show that the surface residual stress predicted by modified method is much closer to the FEM results than the results predicted by McDowell＇s model under the same simulation conditions.展开更多
本文基于产业内贸易理论,运用了格鲁贝尔--劳埃德(G-L)指数、Bruelhart边际产业内贸易指数以及Thom & Mc Dowell垂直和水平型产业内贸易指数,采用了UNCOMTRADE数据中中韩农产品贸易数据进行实证研究。结果显示中国和韩国农产品贸易...本文基于产业内贸易理论,运用了格鲁贝尔--劳埃德(G-L)指数、Bruelhart边际产业内贸易指数以及Thom & Mc Dowell垂直和水平型产业内贸易指数,采用了UNCOMTRADE数据中中韩农产品贸易数据进行实证研究。结果显示中国和韩国农产品贸易主要以产业间贸易为主,在产业内贸易内部,又主要是技术差异主导的垂直型产业内贸易,中韩两国农产品贸易结构存在着很强的互补性。因此,本文探索了中韩两国农产品贸易现状的原因,并提出了相应的政策建议。展开更多
文摘The analytical elastoplastic rolling/sliding model for two-dimensional contact proposed by McDowell is an important tool for predicting residual stress in rolling/sliding processes. In application of the model, a problem of low predicting precision near the surface layer of the component is found. According to the volume- constancy of plastic deformation, an improved algorithm for McDowell＇s model is proposed in order to improve its predicting accuracy of the surface residual stress. In the algorithm, a relationship between three normal stresses perpendicular to each other at any point within the component is derived, and the relationship is applied to McDowell＇s model. Meanwhile, an unnecessary hypothesis proposed by McDowell can be eliminated to make the model more reasonable. The simulation results show that the surface residual stress predicted by modified method is much closer to the FEM results than the results predicted by McDowell＇s model under the same simulation conditions.
文摘本文基于产业内贸易理论,运用了格鲁贝尔--劳埃德(G-L)指数、Bruelhart边际产业内贸易指数以及Thom & Mc Dowell垂直和水平型产业内贸易指数,采用了UNCOMTRADE数据中中韩农产品贸易数据进行实证研究。结果显示中国和韩国农产品贸易主要以产业间贸易为主,在产业内贸易内部,又主要是技术差异主导的垂直型产业内贸易,中韩两国农产品贸易结构存在着很强的互补性。因此,本文探索了中韩两国农产品贸易现状的原因,并提出了相应的政策建议。
