PSI - Issue 28

Michael Jones et al. / Procedia Structural Integrity 28 (2020) 2078–2085 Author name / Structural Integrity Procedia 00 (2019) 000–000

2083

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akin to a crack than a neck, so it is therefore not surprising that the assumptions through which Bridgman developed the necked geometry theory do not hold.

(a)

2,30

(b)

0,30 0,50 0,70 0,90 1,10 0,30 0,80 1,30 1,80 2,30 2,80 3,30 3,80

1,80

1,30

0,80 Triaxiality

Triaxiality

0,30

0,0

0,5

1,0

0,0

0,5

1,0

Normalised load

Normalised load

0,00 0,05 0,10 0,15 0,20 0,25 0,30 0,35 0,00 0,10 0,20 0,30 0,40 0,50 0,60 0,70

(d)

(c)

Triaxiality

Axial strain

0,0

0,5

1,0

0,0

0,5

1,0

Normalised load

Normalised load

(e)

(f)

0,00 0,10 0,20 0,30 0,40 0,50

Axial strain

Axial strain

0,0

0,5

1,0

0,0

0,5

1,0

Normalised load

Normalised load

Figure 6(a)-(g) – Comparison of values determined using Bridgman and FEA for triaxiality in (a) the blunt notch, (b) the medium notch, (c) the small notch and for axial strain in (d) the blunt notch, (e) the medium notch and (f) the small notch.

To understand why the triaxiality does not decrease throughout the test in the FEA models as it did according to Bridgman in the experiments, it is necessary to examine the evolution of the stress components. A decreasing