PSI - Issue 52

Angela Russo et al. / Procedia Structural Integrity 52 (2024) 535–542 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

539

5

3. Results and discussion In this section, the results of the numerical analyses are reported. For each configuration, static analyses have been performed, in order to assess the behaviour of the structure in terms of damage propagation, as well as to identify the local buckling of the delamination and the global buckling of the panel, involving both skin and stringer. 3.1. SS#1 configuration For the SS#1 configuration, characterized by an initial damage of 80 mm, the results in terms of load and evolution of the delaminated area as a function of the displacement are shown in Figure 5. According to the charts, the evolution of delamination is quite unstable, indeed in a limited range of displacements (from 0.75 mm to 0.93 mm) the delamination increases by approximately 113 %.

Load-Displacement

Delaminated area-Displacement

10 15 20 25 30 35 40 45 50

0 1000 2000 3000 4000 5000 6000 7000 8000 9000

SS#1

SS#1

Load [kN]

0 5

Delaminated area [mm2]

0

0.2

0.4

0.6

0.8

1

0

0.2

0.4

0.6

0.8

1

Displacement [mm]

Displacement [mm]

Figure 5. Results of the SS#1 configuration

According to the results, a damage initiation load equal to 41.69 kN has been found. Figure 6 shows the debonding condition at the delamination onset step and at the last step together with deformed shape representing the out-of-plane displacements contour plot. According to the figure, the delamination starts to propagate after skin buckling, while at the analysis last step the global buckling of the panel can be observed. It is worth to specify that the simulation has been terminated by the user as the delamination exceeded a value 100% greater than the initial value (limit specified by the user).

0.8125 mm 51.45 kN 0.75 mm 41.79kN

1.043 mm 42.11 kN 0.75 mm 41.79kN 0.94 mm 33.13 kN

-1.83

-1.36

-.892

-.424

-.046

-5.76

-3.03

-.303

2.43

5.16

-7.13

-4.40

-1.67

1.06

3.79

-2.07

-1.60

-1.13

-.658

-.189

Figure 6. Initial and final debonding – SS#1 configuration