Low-Cycle Fatigue Crack Initiation Simulation and Life Prediction of Powder Superalloy Considering Inclusion-Matrix Interface Debonding

Abstract

From the perspective of damage mechanics, the damage parameters were introduced as the characterizing quantity of the decrease in the mechanical properties of powder superalloy material FGH96 under fatigue loading. By deriving a damage evolution equation, a fatigue life prediction model of powder superalloy containing inclusions was constructed based on damage mechanics. The specimens containing elliptical subsurface inclusions and semielliptical surface inclusions were considered. The CONTA172 and TARGE169 elements of finite element software (ANSYS) were used to simulate the interfacial debonding between the inclusions and matrix, and the interface crack initiation life was calculated. Through finite element modeling, the stress field evolution during the interface debonding was traced by simulation. Finally, the effect of the position and shape size of inclusions on interface debonding was explored.

A coupled plasticity-damage cohesive-frictional interface for low-cycle fatigue analysis

“…Most of the available approaches to low-cycle fatigue degradation are not developed within a thermodynamic framework and the definition of a Helmholtz free energy and the actual dissipation related to material degradation are neither defined nor estimated. Indeed, in most low-cycle formulations, cyclic degradation is often modelled resorting to Peerling-like laws [60], as a function of the cycle stress amplitude, mean stress and number of loading cycles, but no specific thermodynamically consistent evolution laws, functions of the state variables in the loading cycle, are employed.…”

Modeling Crack Initiation in Low Cycle Fatigue: A Review

“…Thermodynamic damage parameter. A study by Zhang et al [35] was able to successfully simulate the fatigue crack initiation at the inclusion-matrix interface. This work was based on the thermodynamic theory of damage mechanics, in which the fatigue damage is regarded as an irreversible thermodynamic process [36].…”

Study on Creep Damage of Ni-Based Superalloy Caused by Variable Load Conditions at Elevated Temperatures

“…Therefore, they are used primarily as materials for parts used at high temperatures, such as aircraft engines and gas turbines for power generation [1][2][3][4]. In general, a turbine is operated at a high temperature, and a load is added through centrifugal force during the operation [5]. Therefore, the material used for the turbine is exposed to creep and fatigue [6][7][8][9][10].…”