Stress/Strain Field around a Crack Tip under the Conditions of Large Scale Yielding and Mixed Mode Loading

• Published in: Transactions of the Japan Society of Mechanical Engineers Series A Vol. 56; no. 523; pp. 559 - 567
• Main Authors: TOHGO, Keiichiro, OTSUKA, Akio, NOJIMA, Yasushi
• Format: Journal Article
• Language: Japanese
• Published: The Japan Society of Mechanical Engineers 1990
• Subjects: Ductile Fracture; Finite Element Method; Fracture Mechanics; Fracture process zone; HRR Singularity; J-integral; Mixed mode
• ISSN: 0387-5008; 1884-8338
• DOI: 10.1299/kikaia.56.559

Large deformation finite element analyses based on Gurson's yield function are carried out for single-edge cracked specimens subjected to bending moment and shearing force, and the stress/strain field around a crack tip under the conditions of large scale yielding and mixed mode loading is examined. The crack tip under mixed mode loading is surrounded by a stress/strain field with HRR singularity, which is uniquely represented by J-integral J, JI and JII (JI: mode I component, JII: mode II component), throughout small scale yielding and large scale yielding. The fracture process zone of the crack tip is discussed based on the distributions of equivalent plastic strain εp and void volume fraction f. The size of the fracture process zone due to εp becomes larger, if the mode II component is more predominant. On the other hand, the size of the fracture process zone due to f becomes larger, if the mode I component is more predominant. The implications of this study on the behavior of ductile crack initiation from a mixed mode crack are also discussed.