PSI - Issue 77

L.A.S. Maia et al. / Procedia Structural Integrity 77 (2026) 87–94 Maia et al. / Structural Integrity Procedia 00 (2026) 000–000

89

3

Fig. 2. DAJ configurations + geometrical modifications.

2.2. Adherends and adhesives The adherend material was DIN 55Si7 steel (Table 1). The selection of this steel ensures no plastic deformation during the tests. Four structural adhesives ranging from brittle to highly ductile were used: the Araldite ® AV138, an epoxy resin, recognized for its strength and brittleness, the Nagase Chemtex XNR6852E-2, a crash resistant epoxy, the Momentive ® RTV106, a highly ductile and temperature resistant silicone adhesive, and the 3M ® DP-8005, a fast curing acrylic adhesive. Table 2 shows the properties of these adhesives (Valente et al. 2019). Bulk specimens are used to estimate E and tensile cohesive strength ( t n 0 ), while the shear modulus ( G ) and shear cohesive strength ( t s 0 ) were determined by Thick Adherend Shear Tests (TAST). Tensile fracture toughness ( G IC ) and shear fracture toughness ( G IIC ) results were obtained from double-cantilever beam (DCB) and end-notched flexure (ENF) specimens, respectively. For the speed of 105000 mm/min, the properties were acquired through logarithmic extrapolation.

Table 1. Evaluated data for the Steel DIN 55Si7 used in the joints.

Young’s Modulus, E (GPa) Tensile yield stress, σ e (MPa) Tensile strength, σ f (MPa) Tensile failure strain, ε f (%)

210

1078 1600

6

Poisson’s ratio, ν

0.3

Table 2. Estimated properties of the adhesives used in the study (Valente et al. 2019).

Adhesive

Test speed [mm/min]

t n 0 [MPa]

t s 0 [MPa]

G IC [N/mm]

G IIC [N/mm]

1

6.3

8.4

1.1

6

DP-8005

100

13

17.4 36.7 30.2 36.2 51.7 1.97

-

-

105000

27.5 41.0 49.9 70.2

1.1

6

1

0.35

0.6

AV138

100

-

-

105000

0.35 2.73

0.6

1

2.3

5

RTV106

100

- -

- -

- -

- -

105000

1

42.9

28.7 33.6 45.8

1.68

18

XNR6852E-2

100

46

-

-

105000

53.7

1.68

18

2.3. Models’ preparation The numerical analysis was conducted using Abaqus ® . The conditions apply to both the SAJ validation study and DAJ work. All simulations were performed using (two-dimensional) 2D models. The adherends and artificial mass for load application were modelled as homogeneous solid elements, while the adhesives were represented by a single row of cohesive elements with triangular damage law (Valente et al. 2019), using a quadratic stress criterion for damage initiation and a linear energetic criterion for fracture. Dynamic simulation requires defining an explicit step,