PSI - Issue 13

Konstantinos Kouzoumis et al. / Procedia Structural Integrity 13 (2018) 868–876 K. Kouzoumis et al. / Structural Integrity Procedia 00 (2018) 000–000

874

7

Table 2: Specimens used for validation

Reference

Flaw orientation

Number of Specimens

Milne and Knee (1986); Brocks et al. (1989); Keller et al. (1987)

External Surface External Surface External Surface Internal Surface Through thickness Through Thickness External Surface External Surface External Surface Through Thickness External Surface Through Thickness External Surface Through Thickness Internal Surface

8 3 3 2 1 3 4 1 1 7 1 4

Trigwell and Williams (1965)

Challenger et al. (1995); Anonymous (1982)

Sciammarella (1985)

12

Sloterdijk (1995)

Demofonti et al. (2002)

Willoughby and Garwood (1981)

Sturm and Stoppler (1989)

33 90

Kiefner et al. (1973)

Fig. 2: Assessment results with and without the 1.2 factor

discontinuity. The results of analyses are illustrated in Fig. 2, where the continuous blue line represents the outer line of all continuous yielding FALs and the magenta dashed line the same for discontinuous yielding. The black dots represent the unmodified BS 7910 solution and the red triangles the one without the factor of 1.2. The scatter observed in Fig. 2 relates to either the formulae used (reference stress / stress intensity factor solutions) or the values of the parameters employed in the formulae (material properties / failure load). Concerning the latest and in particular the fracture toughness values employed in the assessments, they were given in the original references either directly in terms of MPa √ m , derived from fracture toughness testing, or in terms of Charpy energy ( J ) from Charpy tests. The latter relates to a large fraction of the data (123 out of the 173 specimens) provided by Kiefner et al. (1973), where fracture toughness was given in terms of Charpy energy. The translation from Charpy to fracture toughness was done in accordance to the guidance in BS 7910, i.e. including a 5% probability of K mat being lower than the calculated value.