Applied Mathematics and Mechanics (English Edition) ›› 2003, Vol. 24 ›› Issue (10): 1158-1167.

• 论文 • 上一篇    下一篇

RANDOM-FUZZY MODEL FOR THE DUCTILE/BRITTLE TRANSITION

吕震宙1, 岳珠峰2, 冯蕴雯1   

  1. 1. Department of Aircraft Engineering, Northwestern Polytechnical University, Xi’an 710072, P. R. China;
    2. Department of Engineering Mechanics, Northwestern Polytechnical University, Xi’an 710072, P. R. China
  • 收稿日期:2000-03-09 修回日期:2003-05-13 出版日期:2003-10-18 发布日期:2003-10-18
  • 基金资助:

    the Aeronautics Science Foundation of China (00B53010); the Astronautics-Science and Shanxi-Natural-Science Foundation of China

RANDOM-FUZZY MODEL FOR THE DUCTILE/BRITTLE TRANSITION

LÜ Zhen-zhou1, YUE Zhu-feng2, FENG Yun-wen1   

  1. 1. Department of Aircraft Engineering, Northwestern Polytechnical University, Xi’an 710072, P. R. China;
    2. Department of Engineering Mechanics, Northwestern Polytechnical University, Xi’an 710072, P. R. China
  • Received:2000-03-09 Revised:2003-05-13 Online:2003-10-18 Published:2003-10-18
  • Supported by:

    the Aeronautics Science Foundation of China (00B53010); the Astronautics-Science and Shanxi-Natural-Science Foundation of China

摘要: Based on a large experimental sample, the influence of stress triaxiality and temperature have been studied on the growth of micro voids and the ductile/brittle transition (DBT) of 40Cr steel. Ductile and brittle fractures have been investigated simultaneously. The experiments show that the ductile fracture is controlled by the micro void mechanism,and the critical void growth ratio can be used as the criterion of ductile fracture. The brittle fracture is modeled by an embedded penny crack, and a micro stress intensity with a characteristic length can be used as the criterion of the brittle fracture. The DBT is the result of the competition of the two mechanisms. Which exists in the fracture of all specimens simultaneously. The distributions of model parameters were measured experimentally. A random model and a random-fuzzy model for DBT were presented. The comparison between the calculated and experimental results shows that the random-fuzzy model can model the DBT satisfactorily.

Abstract: Based on a large experimental sample, the influence of stress triaxiality and temperature have been studied on the growth of micro voids and the ductile/brittle transition (DBT) of 40Cr steel. Ductile and brittle fractures have been investigated simultaneously. The experiments show that the ductile fracture is controlled by the micro void mechanism,and the critical void growth ratio can be used as the criterion of ductile fracture. The brittle fracture is modeled by an embedded penny crack, and a micro stress intensity with a characteristic length can be used as the criterion of the brittle fracture. The DBT is the result of the competition of the two mechanisms. Which exists in the fracture of all specimens simultaneously. The distributions of model parameters were measured experimentally. A random model and a random-fuzzy model for DBT were presented. The comparison between the calculated and experimental results shows that the random-fuzzy model can model the DBT satisfactorily.

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