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Realization of Fractal Affine Transformation

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Journal of shanghai university(English Edition) 2001年第1期5卷 31-34页

作者： xu jing, LIN yi xia school of electromechanical engineering and automation, shanghai university, shanghai 200072, china school of electromechanical engineering and automation Shanghai University Shanghai China

This paper gives the definition of fractal affine transformation and presents a specific method for its realization and its corresponding mathematical equations which are essential in fractal image construction.

关键词： fractal IFS (iterated function system) affine transformation

Evaluation of the Formula of Stress Intensity Factor K_1 for Semi-Elliptical Surface Crack

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Advances in Manufacturing 2000年第1期4卷 18-21页

作者： xu jing jing, WANG Zhi ling, SHAO Ren xing, wu yi min school of Mechanical and Electronic engineering and automation, shanghai university, shanghai 200072, china school of Mechanical and Electronic engineering and automation Shanghai University Shanghai 200072 China

The stress intensity factor (SIF) of the semi elliptical surface crack in the finite body under extensional stress is sclculated by using the FEM software ANSYS release 5.5. The correction factor M f of SIF at different point along the front of the crack is *** relation between M f and the semi elliptical shape a/c , the relative crack depth a/b , the variation of angle θ , the relative crack width 2c/w and the relative height width ratio h/w are calculated respectively. Finally the application range and the modification of the engineering formula about SIF is proposed.

关键词： FEM semi-elliptical surface crack stress intensity facotor extensional stress finite body

Application of Data mining Method to Improve the Accuracy of Springback Prediction in Sheet Metal Forming

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Journal of shanghai university(English Edition) 2004年第3期8卷 348-353页

作者：许京荆张志伟吴益敏 school of electromechanical engineering and automation Shanghai University Shanghai 200072 P.R. China

A new method was worked out to improve the precision of springback prediction in sheet metal forming by combining the finite element method (FEM) with the data mining (DM) technique. First the genetic algorithm (GA) was adopted for recognizing the material parameters. Then according to the even design idea, the suitable calculation scheme was confirmed, and FEM was used for calculating the springback. The computation results were compared with experiment data, the difference between them was taken as source data, and a new pattern recognition method of DM called hierarchical optimal map recognition method (HOMR) is applied for summarizing the calculation regulation in FEM. At the end, the mathematics model of the springback simulation was established. Based on the model, the calculation errors of springback can be controlled within 10% compared with the experimental results.

关键词： springback prediction pattern recognition genetic algorithm FEM even design idea HOMR data mining.