Influence of flow stress choice on the plastic collapse estimation of axially cracked steam generator tubes

Experimental and Numerical Investigation of Collapse and Burst Pressures for a Valve Housing

“…The basic reference stress concept equations are compiled in Table 2. Herein p Y denotes the plastic yield pressure, while k stands for the flow stress factor ( k = 0.5, recommended for most assessments [10]). For the analyzed housing the plastic yield pressure amounts to 32.2 MPa (see Figure 10).…”

“…Both methods are illustrated in Figure 1A and B. In contrast to the plastic collapse load, the plastic instability load can be defined as the maximum load which the structural component made of a work‐hardening material could withstand (Figure 1A) [8, 10].…”

Failure Assessment Diagram in Structural Integrity Analysis of Steam Generator Tubes

“…Due to the very high ductility of SGT materials, most of these criteria are based on limit load analysis, assuming that the plastic collapse is the prevailing failure mode, Flesch and Cochet (1990), Majumdar (1999b), Lee et al (2001), Tonkovic et al (2008). In fact, this is the case of the minimum wall thickness criterion of the ASME code described above.…”

“…A first disadvantage of these methods is that for a particular cracked geometry and loading condition, different definitions for limit load estimation are available, Huh et al (2006). On the other hand, the choice of a particular flow stress for the material under study has influence on the limit load estimation, Tonkovic et al (2008). Therefore, although limit load analyses seem to be simple in practice, they need extensive supporting experimental data and still further research would be needed in order to validate their applicability.…”

“…As a comprehensive option encompassing both limit load and fracture mechanics analyses, some authors proposed the use of the FAD as the most appropriate assessment technique, capable of predicting failures due to different mechanisms in SGTs, Lee et al (2001), Wang and Reinhardt (2003), Chang et al (2006), Tonkovic et al (2008). Thus, at present, many structural integrity assessment procedures based on the FAD methodology have been included in the most important construction codes and guides (e.g., ASME Section XI, API 579-1/ASME FFS-1, SINTAP and BS 7910).…”