Abstract:

An introduction is given to the theories and procedure used for the development of DD3 single crystal constitutive model which is damage coupled, elastoviscoplastic and macroscopically anisotropic. A detailed deduction, which is based on the continua damage mechanics, is presented for the damage evolution equation of DD3 single crystal. The model composition and their characteristics, with meaningful model constants from engineering viewpoint, are analyzed. The model has a potential of concurrent accounting for creep damage, plastic damage and their interaction due to the special damage evolution equation. The definition methodologies of the model material constants are summarized. The model material constants for 950℃ are practically defined according to available test results. Some simulations are carried out to demonstrate the model and to understand the model′s predictive ability. The simulations of the model to test results of various mechanical behavior show that the model is able to predict mechanical behavior of DD3 single crystal to a certain degree of accuracy and suitable for structural analysis of DD3 single crystal turbine blade.

Key words: DD3 single cr ystal, viscoplasticity, damage evolution, constitutive model