Issue 31

J.A.F.O. Correia et alii, Frattura ed Integrità Strutturale, 31 (2015) 80-96; DOI: 10.3221/IGF-ESIS.31.07 86 experimental data. Fig. 4 gives a general overview of the procedure. The probabilistic fatigue crack propagation fields were evaluated using, alternatively, the probabilistic ε-N and SWT-N fields. The residual stress fields ahead of the crack tip were evaluated in this paper using an elastoplastic finite element model of the CT specimens. END Yes Elastic Stress Analysis Creager‐Paris Solution Elastoplastic Stresses Analysis Neuber or Glinka Approach Elastoplastic Stress  Analysis  FEM σ r = σ max  ‐  σ  K r  (weight function method)  K max,tot and  K tot σ max and  ε/2  P‐ε‐N Weibull field P‐SWT‐N Weibull field  ε‐N exp. data da/dN=ρ*/N f P‐da/dN‐  K‐R field  iterate ρ*  (P‐da/dN‐  K‐R) predicted  vs. (da/dN‐  K‐R) exp. Satisfactory? No First estimate of ρ* Figure 4: Procedure to generate probabilistic fatigue crack propagation fields. E XPERIMENTAL FATIGUE DATA OF THE S355 MILD STEEL he fatigue behaviour of the S355 mid steel was evaluated by De Jesus et al. [19], based on experimental results from fatigue tests of smooth specimens and fatigue crack propagation tests. The fatigue tests of smooth specimens were carried out according to the ASTME606 standard [29], under strain-controlled conditions. Tab. 1 and 2 summarize the elastic ( E : Young modulus) and monotonic strength properties ( f y : yield strength; f u : tensile strength) as well as the cyclic elastoplastic constants ( K’ : cyclic strain hardening coefficient; n’ : cyclic strain hardening exponent) and the strain-life constants (refer to Eq. (3)–(5)). The crack propagation tests were performed using compact tension (CT) specimens, according to the procedures of the ASTM E647 standard [30], under load-controlled conditions. Fig. 5 T