Nonlinear fatigue life prediction model based on isodamage curve
considering two-block loading
Abstract
A non-linear life prediction model considering the loading history is
proposed based on isodamage curve. The stress-controlled low-high block
loading at high temperature, with variously previous cycles, was
performed on a nickel-based superalloy. The damage evolvement of the
prior loading was revealed using scanning electron microscopy under the
low-high block loading, especially the failure mechanism of coaxing
effect. In addition, load history correlation factor was introduced to
describe the influence of prior-cycle. Based on the Ni-based superalloy,
the life prediction model of two-step loading, including the low-high
block (LH) and high-low block loading (HL), was proposed, agreeing well
with the experimental results for different metals. Comparing with other
life prediction models, the proposed model demonstrated the higher
prediction accuracy and wider applicability.