Yield criterion and crack tip plastic zone of nickel-based single crystal
- Paper number
IAC-11,C2,9,8,x9543
- Author
Ms. Yang Lihong, China
- Year
2011
- Abstract
Nickel-base single crystal was special one of the orthotropic composites. Because of its excellent anti-fatigue and anti-creep in high temperature condition, nickel-base single crystal had become the key material to blades of aircraft engines and gas turbines. In the past few years, many states had paid much more attention to the development and research of the nickel-base single crystal and had obtained a series of meaningful results. In the elastic-plastic analysis of the orthotropic composites, Hill yield criterion was most widely used. But it did not consider the tension-shear stress coupling of the orthotropic composite, which may lead to larger errors while analyzing non-crystal-axial loading problems. In this paper, a modified Hill yield criterion considering tension-shear stress coupling was given and the material parameters in this criterion for nickel-based single crystal were determined by the Least Square Method. Fracture and crack problem was one research focus in the field of engineering mechanics. There was close contact between shape and size of crack tip plastic zone and crack propagation, and so studying the crack problems of nickel-base single crystal had great engineering significance. Crack tip plastic zones of nickel-based single crystal plate were analyzed by Hill yield criterion and the modified Hill yield criterion given in this paper and the plastic zones corresponding to mixed mode I, II crack were derived. The crack tip plastic zones of nickel-based single crystal were compared to that of isotropic material. The influences of tension-shear stress coupling, compound ratio of mixed mode I, II crack and temperature on crack tip plastic zones were discussed. The results obtained in this paper indicated that the increasing rate of crack tip plastic zones with compound ratio of mixed mode I, II crack in the plane stress condition is greater than that in the plane strain condition for nickel-based single crystal. Temperature had greater influence on the size of crack tip plastic zones and the size of plastic zones significantly increased with the increase of temperature. Key words: Nickel-based single crystal; Modified Hill yield criterion; Mixed mode I, II crack; Plastic zone; Temperature
- Abstract document
- Manuscript document
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