Viscoplastic constitutive model for Ni-based directionally solidified superalloy: Experimental validation on notched specimen

Viscoplastic constitutive model considering strain rate sensitivity under multiaxial thermomechanical fatigue loading

“…Hosseini et al 54 described the loading dependency of inelastic strain rate by using a biterm viscoplastic equation and then especially investigated the expression ability of the developed model in the following aspects, including negative creep, anelastic recovery, stress relaxation, constant‐loading creep, and the effect of prior loading. Considering the effects of temperature, applied stress and anisotropy, Shi et al 55 obtained the analysis result that is consistent with the surface strain fields of notched DZ125 specimens measured by the test system based on high‐temperature digital image correlation. In the study of Morch et al, 56 a double‐exponential formulation was used to describe the relationship between material constants and temperature, which can model the cyclic hardening that is not monotonous with temperature.…”

“…About the application in the field of mechanical science, the unified viscoplastic constitutive models are widely adopted in the expression of cyclic mechanical response of materials and structural design of components at high temperature 47–66 . For example, Wang et al 47 combined Kachanov damage evolution equation and an anisotropic tensor into the Chaboche model to describe the anisotropic mechanical response; then, the creep process was simulated by the finite element software with the subroutine of the modified model for a hollow turbine blade.…”

“…About the application in the field of mechanical science, the unified viscoplastic constitutive models are widely adopted in the expression of cyclic mechanical response of materials and structural design of components at high temperature. [47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66] For example, Wang et al 47 combined Kachanov damage evolution equation and an anisotropic tensor into the Chaboche model to describe the anisotropic mechanical response; then, the creep process was simulated by the finite element software with the subroutine of the modified model for a hollow turbine blade. Zhang and Xuan 48 introduced a cyclic softening term to modify the kinematic hardening rule and proposed a linear term and a static recovery term to modify the isotropic hardening rule, which can describe the decelerated stress relaxation and the accelerated cyclic softening for the material at high temperature.…”

Creep‐fatigue behavior of thin‐walled plate with holes: Stress state characterization and life estimation

“…To investigate the crack initiation and propagation behavior of tested specimen, DIC equipment was used to monitor the displacement change of surface spots during the test. The test system includes the electronic test system (WDW‐100), the high temperature furnace, the cooling system, a high‐resolution digital camera with 2448 × 2050 pixel and the image processing software VIC‐2D, as shown in Figure 2 26 . For speckle treatment, a random distribution artificial pattern was sprayed on the surface of thin plate with holes by high temperature spray paint.…”

“…The test system includes the electronic test system (WDW-100), the high temperature furnace, the cooling system, a high-resolution digital camera with 2448 Â 2050 pixel and the image processing software VIC-2D, as shown in Figure 2. 26 For speckle treatment, a random distribution artificial pattern was sprayed on the surface of thin plate with holes by high temperature spray paint. DIC-based in-situ creep-fatigue tests were performed to monitor the crack initiation and growth at 850 C. The test matrix is listed in Table 3.…”