PSI - Issue 17

Konstantinos Kouzoumis et al. / Procedia Structural Integrity 17 (2019) 347–354 Konstantinos Kouzoumis / Structural Integrity Procedia 00 (2019) 000 – 000

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Table 1: Geometric Properties, Test Temperatures, and failure loads of specimens assessed

ID in (Hadley, 2018) ID, original work

Crack Size (2a), mm

Nominal Thickness, mm

Test Temp., o C

Biaxiality Ratio, k

P 1 at failure (kN)

#40 #41

M01-26 M01-28 M01-27 M01-27

203 200

50 50 50 50

-100 -100 -104 -104

1 0 2

5686 8718 6380 6296

#41a(1) #41a(2)

202.4 202.4

0.5

Figure 1: Geometry of of (a) biaxially loaded, (b) uniaxially loaded specimens

3. Mechanical Properties

3.1. Tensile properties

Tensile properties for the tested plates were originally measured only at +70 o C (Phaal et al., 1995), however in later work assessing specimens of this material at lower temperatures (Hadley, 2018) the stress strain curve was shifted upwards, following the increase of yield strength value as temperature decreases, to a temperature of -95.5 o C. This curve will be used for the Option 3 assessments of all specimens. Regarding the Option 1 assessments the yield stress and ultimate tensile strength were recalculated in accordance with the standard approach of BS 7910:2013, shown in Table 2, while the elastic modulus was taken as 212GPa.

Table 2: Calculated Yield and Ultimate Tensile stresses (MPa) k=0, k=1 ȋǦͳͲͲ ‘ Ȍ k=0.5, k=2 ȋǦͳͲͶ ‘ Ȍ σ › ȋ ƒȌ σ ȋ ƒȌ σ › ȋ ƒȌ σ ȋ ƒȌ ͸ͳ͸ ͹͵ͺ ͸ʹ͵ ͹ͶͶ

3.2. Fracture toughness

Fracture toughness ( K mat ) was measured from a variety of specimen geometries (e.g. C(T) and Charpy) and thicknesses. The analysis of the existing fracture toughness data in (Hadley, 2018) allowed for a Master Curve approach. The reference temperature of the Master Curve, T 0 = -151.3 o C, is used to calculate fracture toughness that correspond to the 5% and 20% probability, i.e. a 5% and 20% probability of the toughness to be lower. As advised by BS 7910 for lower shelf transitional behavior based on the Master Curve, the 5% values will be used for the Option 1 assessments while for the more detailed Option 3 assessments 5% and 20% will both be used for comparison. All the values included in the assessments are shown in Table 3.