Crack Paths 2012

and material properties for 1050 N and 1050 Q T steels as well as 304L stainless steel

can be found in [13, 15]. In addition to the 1050 steel data in N and Q T conditions and

304L stainless steel crack growth data generated for this study, tubular specimen crack

growth data for 1045 steel in normalized (N) condition and for Inconel 718 data under

various loading paths as summarized in [11] were also utilized.

The loading paths analyzed are presented in Fig. 2. Strain paths B, K, and L represent

torsion (shear) cycles with no mean, with tensile normal mean stress/strain, and with

compressive normal mean stress/strain, respectively. These paths were used to study the

effect of closure on crack growth behavior. Strain paths C for in-phase (IP) and N for

90º out-of-phase (OP) loading were used to investigate effects of load non

proportionality on crack growth behavior. Effects of axial and/or torsion mean stresses

on crack growth were studied employing strain paths E, F, G, H, J, and O. Crack growth

behavior under biaxial tension-tension loading was investigated by using load paths, U,

V, and W.

1: Inc 718

2: 1045 N

3: Inc 718 and 1045 N

4: Inc 718, 1045 N, 1050 N,

1050 QT, and 304L SS

Figure 2. Load paths used to study various effects on crack growth behavior [11]. The

superscript on each path code identifies the material(s) for which the load path was used.

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