PSI - Issue 57

Yuki Ono et al. / Procedia Structural Integrity 57 (2024) 290–297 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

292

3

geometry analysis. Fig. 2 shows an example of 2D geometry profile. Microscopic geometrical imperfection introduced by HFMI can be captured as in Fig. 2 (c). Weld size and HFMI-treated groove size were characterized by measuring the weld leg length ( l x , l y ), weld angle ( θ ), groove radius ( ρ ), groove depth ( d ), and groove width ( w ) from the 2D sections; see Figs. 2 (a) and (b). Table 1 shows the measurement results with average values and standard deviations.

ͲϭϲϬϬϬ 16.0

8.0

ͲϰϬϬϬ 4.0

ͲϴϬϬϬ

(a)

(b)

(c)

ͲϭϰϬϬϬ 14.0

7.0

ͲϳϬϬϬ

ͲϯϴϬϬ 3.8

ͲϭϮϬϬϬ 12.0

6.0

ͲϲϬϬϬ

ͲϭϬϬϬϬ 10.0

ͲϯϲϬϬ 3.6

ͲϴϬϬϬ 8.0

5.0

ͲϱϬϬϬ

y (mm)

y (mm)

y (mm)

ͲϯϰϬϬ 3.4

ͲϲϬϬϬ 6.0

l y

4.0

ͲϰϬϬϬ

ρ

d

ͲϰϬϬϬ 4.0

ͲϯϮϬϬ 3.2

3.0

ͲϯϬϬϬ

l x

ͲϮϬϬϬ 2.0

w

ͲϯϬϬϬ 3.0

Ϭ 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 x (mm) 0.0 ͲϭϲϬϬϬ ͲϭϰϬϬϬ ͲϭϮϬϬϬ ͲϭϬϬϬϬ ͲϴϬϬϬ ͲϲϬϬϬ ͲϰϬϬϬ Ϭ ͲϮϬϬϬ

2.0

ͲϮϬϬϬ

ͲϳϬϬϬ 7.0

ͲϳϮϬϬ 7.2

ͲϳϰϬϬ 7.4

ͲϳϲϬϬ 7.6

ͲϳϴϬϬ 7.8

ͲϴϬϬϬ 8.0

ͲϵϬϬϬ 6.0 7.0 8.0 9.0 ͲϴϬϬϬ ͲϳϬϬϬ ͲϲϬϬϬ

ͲϭϬϬϬϬ 10.0

ͲϭϮϬϬϬ 11.0 12.0 ͲϭϭϬϬϬ

x (mm)

x (mm)

Table 1 Measurement results of HFMI groove geometry and weld size Fig. 2 An example of 2D geometry profile around HFMI-treated region

Weld leg length, l y (mm)

Weld leg length, l x (mm)

Weld angle, θ (°)

Groove radius, ρ (mm)

Groove width, w (mm)

Groove depth, d (mm)

The number of sample

Ave 35.1

Stdv 2.55

Ave 4.67

Stdv 0.43

Ave 6.64

Stdv 0.35

Ave 1.87

Stdv 0.24

Ave 2.42

Stdv 0.30

Ave 0.13

Stdv 0.04

532

3. Numerical analysis 3.1 FE models

FE simulations were performed on the specimens to clarify the relaxation of residual stress and fatigue damage. The global 2D model of the transverse attachment considered in this study is shown in Fig. 3. This study only focused on the behavior of HFMI-treated region, i.e., fatigue critical weld toe of non-load carrying fillet weld. Linear plane strain elements were used. Finite strain theory was applied to represent the large displacements and material non linearity. The FE-models include partitions as shown in Fig. 3 to consider different material properties: base material (BM), weld metal (WM), heat-affected zone (HAZ), and HFMI-treated zone (HFMI). Combined non-linear isotropic

Material section

1 mm

WM

Fix (Ux, Uy, URz)

HAZ

Fix (Uy, URz)

HFMI

Loading

10 mm

BM

Fig. 3 Global model of transversal attachment, boundary condition zone, and material section Table 2 Voce- Chaboche’s (VC) parameters for each material section

Istropic hardening

Kinematic hardening

Weld metal (WM) Base material (BM) Heat affected zone (HAZ) Material

E [MPa]

σ y [MPa]

Q [MPa]

C 1 [MPa]

C 2 [MPa]

q

γ 1

γ 2

208000 226000 226000 249000

530 745 781 853

140

104

16448 12846 12846 10550

285 198 198 255

13233 12846 12846 15915

285 198 198 255

1 1 1

1 1 1

HFMI-treated zone (HFMI) E : Young modlus, Q : Maximum increase in size of yield surface due to hardening at saturation, q : How quickly the increase of yield surface approaches the saturation, σ y : Yield stress at zero plastic strain, C : Initial kinematic hardening mudlus, γ : Rate at which the kinematic hardening modulus decreases with increasing plastic deformation