PSI - Issue 5

Sameera Naib et al. / Procedia Structural Integrity 5 (2017) 1417–1424 Naib et al./ Structural Integrity Procedia 00 (2017) 000 – 000

1423

7

The eq,pl-max  points remain 45 0 at initial stages of plastic deformation when the strains are the highest around the crack tip. At this point, the equivalent plastic strains are small in base material. The experimental and numerical results show a similar trend but the deviation in initial plastic deformation lines is due to the mismatch in choosing total equivalent strains in simulations (equivalent plastic strains) and experiments (equivalent elastic-plastic strains). Nevertheless, this difference does not affect the outcome of this study.

20

20

45 0 line

45 0 line

15

15

10

10

5

5

Y Distance (mm)

Y Distance (mm)

Max deformation Plasticity initiation

Notch

Notch

Max deformation Plasticity initiation

0

0

-15

-10

-5

0

5

10

15

-15

-10

-5

0

5

10

15

X Distance (mm)

X Distance (mm)

(a)

(b)

eq,pl-max  obtained from simulations at the onset of plasticity and at maximum deformation for the specimens having

Figure 6: The values of

notch located in (a) OM region and (b) in the UM region

10

10

45 0 line

45 0 line

5

5

0

0

-5

-5

Y Distance (mm)

Y Distance (mm)

Max deformation Plasticity initiation

Max deformation Plasticity initiation

Notch

Notch

-10

-10

-15

-10

-5

0

5

10

15

-15

-10

-5

0

5

10

15

X Distance (mm)

X Distance (mm)

(a)

(b)

eq,pl-max  obtained from DIC analysis at the onset of plasticity and at maximum deformation for the specimens having

Figure 7: The values of

notch located in (a) OM region and (b) in the UM region

4. Conclusions

In this paper, the applicability of slip line field theory to analyze plastic deformations in a welded Single Edge notched Tension (SE(T)) has been investigated using Finite Element (FE) modelling and experimental testing. The investigated weld has a double V configuration containing a strength overmatching (OM) and strength undermatching (UM) region. Test was performed on samples having a notch in OM and UM regions. By inspecting the maximum equivalent (plastic) strain values and maximum shear stress values, it is shown that the assumptions of von Mises yield criteria ( eq,pl-max  ) or Tresca yield criteria does not affect observed slip line trajectories significantly. This shows that the slip line theory is a valuable tool to assist the assessment of defects in tension loaded heterogeneous welds. Equivalent (plastic) strain values were obtained during plastic deformation of SE(T) samples in simulations and experiments and slip line trajectories were assessed. The simulation model was validated with the experiments, paving