PSI - Issue 60

Amardeepa KCS et al. / Procedia Structural Integrity 60 (2024) 60–74 Amardeepa KCS/ StructuralIntegrity Procedia 00 (2023) 000–000

71

12

19.300 mm

21.439mm

17.161mm

27.098 mm

27.098 mm

23 mm

(a) stress location between layers 1-2 (15 th row)

(b) stress location between layers 1-2 (16 th row)

(c) stress location between layers 1-2 (17 th row)

Fig. 25. Stress location at zone 2

Table 2. Summary of the enforced displacement values and induced stress values, along with their location

Zone 2

Zone 3 and 4

Max displacement applied

Failure spot Normal Stress

Failure spot Resultant shear stress for Plane 1 &2

Failure spot

Normal Stress

Failure spot

Failure spot Axial stress

Resultant shear stress for Plane 1 &2

Failure spot Axial stress

[1] 0.7 1.5 2.3 2.4 2.5 2.6 2.7 2.8

[2]

[3]

[4]

[5]

[6]

[7]

[8]

[9]

[10]

[11]

[12]

[13]

11.10 23.56 36.11 37.67 38.46 39.24 40.80 42.36 43.94

Fig. 25 (a) 7.92 Fig. 25 (a) 17.9 Fig. 25 (a) 28.0

Fig. 25 (b) 13.25 Fig. 25 (a) 16.74 Fig. 25 (c) 28.20 Fig. 25 (a) 19.87 Fig. 25 (c) 43.30 Fig. 25 (a) 31.02

Fig. 26 (a) 8.19

Fig. 26 (e) 20.90 Fig. 26 (a)

Fig. 26 (b) 18.99 Fig. 26 (e) 31.86 Fig. 26 (d) Fig. 26 (c) 29.91 Fig. 26 (e) 49.78 Fig. 26 (e) Fig. 26 (c) 31.28 Fig. 26 (e) 52.02 Fig. 26 (e) Fig. 26 (c) 31.96 Fig. 26 (e) 53.13 Fig. 26 (e) Fig. 26 (c) 32.63 Fig. 26 (e) 54.25 Fig. 26 (e) Fig. 26 (c) 33.99 Fig. 26 (e) 56.47 Fig. 26 (e) Fig. 26 (c) 35.35 Fig. 26 (e) 58.70 Fig. 26 (e) Fig. 26 (c) 36.73 Fig. 26 (e) 60.96 Fig. 26 (e)

Fig. 25 (a) 29.27 Fig. 25 (c) 45.19 Fig. 25 (a) 32.33 Fig. 25 (a) 29.89 Fig. 25 (c) 46.13 Fig. 25 (a) 32.98 Fig. 25 (a) 30.52 Fig. 25 (c) 47.07 Fig. 25 (a) 33.62 Fig. 25 (a) 31.78 Fig. 25 (c) 48.95 Fig. 25 (a) 34.92 Fig. 25 (a) 33.04 Fig. 25 (c) 50.83 Fig. 25 (a) 36.22

2.45

Fig. 25 (a) 34.3

Fig. 25 (c) 52.73 Fig. 25 (a) 37.55

Note: Stress values given in [2] are acting in Fig [3] and so on [4] [5]; [6] [7];

Figure 25 & 26 shows where the layers start to fail in the curved region of zones 2,3 and 4respectively. The results are tabulated in Table 2 for all 9 classes of displacement values given in Table 1 for quick reference. Figure 27 shows the comparison of strain values of the standalone L angle with that of the wing box, which is within 8-10% of the difference range. Figure 28 shows the Failure Index values extracted for each sub-laminate that consists of different layers and orientations as per the modelling approach adopted in this study. Figure 29 shows the variation of the maximum resultant shear stress, normal stress, and axial stress values computed by applying various displacement values on a standalone L angle. Figure 29 shows two constant horizontal lines at different levels, indicating the line of allowable shear strength value of 23 MPa, and allowable transverse tensile strength value of 53 MPa. These allowable strength values remain the same for all cases considered. It is inferred from Figure 29 that the L angle fails in shear between layers (1-2) when the applied internal fuel pressure increases from 12.5 PSI to 26.78 PSI (12.50 PSI x1.50 mm / 0.70 mm linearly interpolated between enforced displacements and applied internal fuel pressure), and the same L angle fails in tension across the composite layers (1-2) as it reaches its allowable transverse tensile strength value at 42 PSI arrived at by the similar linear interpolation at a displacement of 2.4 mm; however, the first ultimate failure load of the L angle is estimated to have occurred at an internal fuel pressure of 26.78 PSI which is more than