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Fatigue life assessment of welded joints made of the stainless steel X6CrNiNb18‐10 for thermomechanical and variable amplitude loading
Author(s) -
Bosch A.,
Vormwald M.,
Schackert S.,
Schweizer C.
Publication year - 2018
Publication title -
materialwissenschaft und werkstofftechnik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.285
H-Index - 38
eISSN - 1521-4052
pISSN - 0933-5137
DOI - 10.1002/mawe.201700196
Subject(s) - welding , hot work , metallurgy , amplitude , structural engineering , fatigue testing , materials science , engineering , physics , tool steel , quantum mechanics
Abstract The aim of the presented work is to develop improved concepts for the prediction of fatigue lifetime under variable amplitude loading including plastic deformation and thermomechanical fatigue of welded joints made of the austenitic stainless steel 1.4550. Local strain amplitudes are located in the regime of low cycle fatigue, which is dominated by short crack growth. This can best be described by nonlinear fracture mechanics. To develop a fracture mechanics based lifetime model, different experiment types are carried out to estimate the influence of loading history, thermal cycling, and mean stresses. For the evaluation, different estimation concepts based on Palmgren‐Miner's classic linear damage accumulation rule are used: solely calculated by strain ranges, damage parameter established by Smith, Watson and Topper, and a damage parameter based on the cyclic effective J‐integral. The differences in the concepts are highlighted and used for further considerations on how to improve the lifetime prediction models.