Anaysis of fatigue crack growth in pin-loaded lug jionts under inelastic deformations

摘要

Results of an examperimental program on fatigue crack growth in an interference fit lug joint and numerical estimation of relevant fracture parameters to correlate the experimental data are presented in this paper. Fatigue crack growth rates of naturally initiating cracks, were estimated fractographically as a function of crack length for lug joints fitted with different levels of interference. The fracture parameters to correlate the crack growth behavior were estimated using a two-dimensional materially nonlinear contact stress finite element analysis. A path-independent integral, DETLTA T_p~*, computed for incremental loads and summed up (I) during cyclic loading was used as an elasto-plastic fracture parameter. Correlation of the experimental crack growth data and the evaluated range of DELTA T resulted in a power law similar to the Paris equation. Further, the fatigue crack groth (FCG) rate was evaluated using the relationship between low cycle fatigue (LCF) parameters and the frqacture parameter, DELTA T, as estimated. These are in good agreement with the experimental results.