پديدآورندگان :
Loghmanzadeh A. Graduate Student, Department of Mechanical Engineering, School of Engineering, Persian Gulf University, Bushehr, Iran , Golbahar Haghighi M.R. Associate Professor, Department of Mechanical Engineering, School of Engineering, Persian Gulf University, Bushehr, Iran , Ahmadzadeh G. R. reza.ahmadzadeh@ryerson.ca Visiting Professor, Department of Mechanical Engineering, Ryerson University, Toronto, Ontario M6L N2B Canada;
كليدواژه :
Variable loading , critical plane , cycle counting , Mohr’s circle , fatigue life prediction
چكيده فارسي :
The intention of this study is to estimate fatigue damage and life of different steel alloys under uniaxial variable amplitude loading conditions based on three critical plane strain-based models. Fatemi-Socie (FS) damage model evaluates fatigue lives of the samples based on the shear strain and normal stress acting on critical plane where maximum shear strain takes place. The assessment of fatigue damage by means of the Macha model is based on linear summation of shear and normal strain whereas Carpinteri-Spagnoli (CS) model involves both axial and shear strain in the nonlinear form on critical plane. Uniaxial variable loading spectra is counted and partitioned into the number of reversals by means of the rainflow cycle counting method. The largest stress and strain Mohr’s circles over the counted reversals are constructed to determine the maximum shear strain magnitude and corresponding stress to evaluate damage of each reversal. The total damage over entire loading history is then calculated based on the linear damage rule of Miner. The predicted lives based on three damage models are compared with those of reported experimental data. Fatigue life data evaluated by Macha and CS criteria with different descriptions show a closer agreement to the experimentally obtained fatigue lives of steel samples.
