A non-linear damage accumulation fatigue model for predicting strain life at variable amplitude loadings based on constant amplitude fatigue data

Abstract

A new phenomenological technique for using constant amplitude loading data to predict fatigue life from a variable amplitude strain history is presented. A critical feature of this reversal-by-reversal model is that the damage accumulation is inherently non-linear. The damage for a reversal in the variable amplitude loading history is predicted by approximating that the accumulated damage comes from a constant amplitude loading that has the strain range of the particular variable amplitude reversal. A key feature of this approach is that overloads at the beginning of the strain history have a more substantial impact on the total lifetime than overloads applied toward the end of the cycle life. This technique effectively incorporates the strain history in the damage prediction and has the advantage over other methods in that there are no fitting parameters that require substantial experimental data. The model presented here is validated using experimental variable amplitude fatigue data for three different metals.

A Review on Fatigue Life Prediction Methods for Metals

“…Hashin and Rotem [151], Ben-Amoz [152], Subramanyan [153], and Leipholz [154] proposed in the past a variety of life curve modification theories; also various nonlinear cumulative damage fatigue life prediction methods can be found in literature [155][156][157][158].…”

Residual fatigue life prediction based on a novel damage accumulation model considering loading history

“…However, the linear damage accumulation rule would result in an overestimated fatigue life in the case of HL block loading and a shorter predicted fatigue life in the LH loading path . To overcome this shortcoming, numerous nonlinear cumulative fatigue damage models had been proposed considering the influence of loading history . Fatemi et al and Schijve comprehensively reviewed the accumulative fatigue damage models with detailed discussion on the influencing factors.…”

“…[10][11][12] To overcome this shortcoming, numerous nonlinear cumulative fatigue damage models had been proposed considering the influence of loading history. [13][14][15][16][17][18][19] Fatemi et al 10 and Schijve 20 comprehensively reviewed the accumulative fatigue damage models with detailed discussion on the influencing factors. Nonlinear damage accumulation theories are generally categorized as S-N diagram related, 21 crack growth related, 22 continuum damage mechanics related, 23 and strain energy related.…”

Cumulative Fatigue Damage: CDM-Based Engineering Rule and Life Prediction Aspect

“…Apparently, the dependence of exponent on stress must be uncovered by experimental means and this does not appear to be an easy task. More than 100 nonlinear damage rules have been proposed, as double linear rule and damage curve approaches, life curve approaches, energy methods, stochastic modifications, or other theories . Comprehensive reviews of the above fatigue damage models categories can be found elsewhere .…”