A multiaxial probabilistic fatigue life prediction method for nickel‐based single crystal turbine blade considering mean stress correction

Abstract

Gas turbine blades normally operate under high-temperatures, extreme pressure, and high-speed conditions, which leads to complex failure mechanisms and difficulties in fatigue life assessment. Moreover, due to the randomness of manufacturing errors, working loads, and material properties, the low cycle fatigue (LCF) life normally presents unavoidable stochastic behavior. Therefore, accurate and efficient fatigue life prediction is critical for the design of gas turbine blades. Accordingly, this paper analyzes the effects of mean stress, anisotropy, and uncertainties on the LCF life of nickel-based single-crystal turbine blades. The modified Hill yield criterion is employed to deal with the anisotropic damage characteristics of nickel-based single-crystal superalloy (NSCS) under a multiaxial stress state. Meanwhile, the effects of the temperature and crystal orientation are introduced into the walker mean stress correction term. A multiaxial LCF life prediction model is developed based on the energy criterion-based fatigue life estimation method. Moreover, multi-source uncertainties originating from rotation speeds, material properties, and temperature are analyzed and quantified. Comparison between the predicted and tested life indicates that the proposed method produces good accuracy and robustness, which can provide a reference for the reliability design of NSCS turbine blades.

Dynamic response and safety analysis of polyethylene pipeline under rockfall conditions

“…Creating a finite element analysis model for a buried pipeline exposed to rockfall requires careful consideration of the soil mass effect. 18,19 ABAQUS software provides a range of constitutive models that can precisely describe soil mass. 20 Although soil mass can be treated as an elastic material for simple problems, the elastic-plastic model is the widely preferred approach in geotechnical simulations.…”

“…Creating a finite element analysis model for a buried pipeline exposed to rockfall requires careful consideration of the soil mass effect 18,19 . ABAQUS software provides a range of constitutive models that can precisely describe soil mass 20 .…”

Fatigue reliability assessment of offshore catenary risers conveying internal slug flow

“…Fatigue is often quantified using the Palmgren-Miner rule, which predicts the fatigue of a structure subjected to a sequence of cyclic loading based on the accumulated damage from each cycle. [31][32][33] The number of cycles that a structure can withstand before failure depends on the stress amplitude by referencing the S-N curve, which relates the number of cycles to failure for a given stress amplitude. 34 For offshore risers, the axial stress S at a specified time t can be obtained by the tension T e and bending moment M b as:…”

Numerical Simulation of the Residual Stress at the Interface between Thermal Barrier Coating and Nickel-Based Single-Crystal Superalloy Based on Crystal Plasticity Theory

“…Turbine blades work in an environment where multiple physical fields interact (high speed, high pressure, and high-temperature coupling) and mainly bear three kinds of loads: centrifugal load, temperature load, and aerodynamic load. In the actual work of blades, the blade stress generated by centrifugal force is much greater than that generated by vibration load and gas force, and the vibration load and gas force basically do not change the stress/strain distribution of blades [43]. Therefore, in order to more accurately analyze the stress and strain of turbine blades under actual working conditions and the operation of the slip system, a uniformly distributed centrifugal force load is applied to the right boundary of the finite element model.…”