PSI - Issue 31

J. Lukács et al. / Procedia Structural Integrity 31 (2021) 51–57 J. Lukács et al. / Structural Integrity Procedia 00 (2019) 000–000

53 3

Integrity of a structure can be assessed using FEM or XFEM (e.g. Zaidi et al., 2020; Shin et al., 2020 or Solob et al., 2020) and/or investigations (e.g. Radu et al., 2020). The present study introduces our full-scale tests program, where fatigue and burst tests were performed on repaired pipeline sections containing artificial surface and through wall, separate and interacting flaws. Different composite reinforcing methods, in other words wrap systems, were used, investigated and compared. The main objective of the ongoing research is data collection for integrity management tasks, which can help the operators in a decision situation: can be applied the composite repairing system (wrap system) for a long-term; or it is only appropriate for a short-term maintenance period. 2. Investigations Seam welded and seamless steel pipeline sections without girth welds were examined. Table 1 summarizes the main characteristics of the investigated pipeline sections and the fatigue tests. Four different types (W1-W4) of fiber reinforced polymer matrix composite systems (wrap systems) were used for external reinforcing of artificial flaws. During this research period, one unreinforced and seven reinforced pipeline section were investigated. Table 1. Main particularities of the investigated pipe sections and internal pressure values during the full-scale fatigue tests. Pipe section Pipe material Pipe type D ( mm ) t ( mm ) Wrap system p min ( bar / MPa ) p max ( bar / MPa )

PS-A1 PS-A2

L360MB

seam welded

323.9

7.1

without wrap (WW) 31.5 / 3.15

63.0 / 6.30

type1 wrap (W1) type2 wrap (W2)

PS-B1-1 PS-B1-2 PS-B2-1 PS-B2-2 PS-B3-1 PS-B3-2

X52

seamless

324.7

10.65

51.0 / 5.10 39.0 / 3.90 51.0 / 5.10 39.0 / 3.90 51.0 / 5.10 39.0 / 3.90

63.0 / 6.30 63.0 / 6.30 63.0 / 6.30 63.0 / 6.30 63.0 / 6.30 63.0 / 6.30

8.4

X52

seamless

327.2

10.2 8.45 10.4

type3 wrap (W3)

X52

seamless

327.9

type4 wrap (W4)

8.5

Because of metal losses are the significant discontinuities in real transporting pipelines, different types of artificial flaws, as characteristic metal losses were investigated. The types and the dimensions of the artificial flaws, furthermore the applied wrap systems can be seen in Table 2.

Table 2. Artificial flaw types, their particularities and the applied wrap systems. Pipe section Artificial flaw(s) type(s) l f ( mm ) d f ( mm )

d h ( mm )

Wrap system

PS-A1-No1

longitudinal gouge circumferential gouge

100 130

3.0 4.7 4.0 3.0 3.1 3.0 4.7 4.0

N/A N/A N/A N/A N/A N/A N/A N/A

without wrap (WW)

interacting circumferential gouges

2 * 130

PS-A1-No2 PS-A1-No3 PS-A2-No1

longitudinal gouge

100 100 100 130 N/A N/A N/A N/A N/A N/A N/A

without wrap (WW) without wrap (WW) type1 wrap (W1)

new longitudinal gouge longitudinal gouge circumferential gouge

interacting circumferential gouges

2 * 130

PS-A2-No2

new longitudinal gouge

N/A N/A N/A N/A N/A N/A N/A

3.0 3.0 3.0 3.0 3.0 3.0 3.0

type1 wrap (W1) type2 wrap (W2)

PS-B1-1 PS-B1-2 PS-B2-1 PS-B2-2 PS-B3-1 PS-B3-2

through hole through hole through hole through hole through hole through hole

type3 wrap (W3)

type4 wrap (W4)