PSI - Issue 66

255 9

Akash Shit et al. / Procedia Structural Integrity 66 (2024) 247–255 Shit and Prakash/ Structural Integrity Procedia 00 (2025) 000–000

a

b

CASE ‐ 1

CASE ‐ 2

Without shadow Crack CASE ‐ 1 CASE ‐ 2

‐ 4,00% ‐ 3,00% ‐ 2,00% ‐ 1,00% 0,00% 1,00% 2,00% 3,00% 4,00%

1000 1200 1400

% decrement of K_eff w.r.t without shadow crack

0 200 400 600 800 K_effective, MPa.mm^0.5

30 32 34 36 38 40 42

32 34 36 38 40

Crack length (2a), mm

Crack length (2a), mm

Fig. 10. (a) Comparison of effective SIF at crack tip-2 of Hole-1 (b) % difference in effective SIF at crack tip-2 of Hole-1 w.r.t the absence of shadow crack at Hole-2 and Hole-3 due to the shadow crack at Hole-2 and Hole-3. 4. Conclusions Numerical simulations were conducted to evaluate the effective Stress Intensity Factor (SIF) for 3-2-1 Lozenge pattern riveted joints under in-plane tension-tension biaxial loading, using a cruciform specimen as the strap plate and employing the Maximum Energy Release Rate (MERR) criteria for crack propagation. Hole at 1 was identified as the most critical location, exhibiting SIF values 70%, 66%, and 62% higher than Holes at 5, 4, and 3, respectively. The study investigated the influence of load ratio on effective SIF and observed significant reductions as the load ratio decreased. The maximum reduction of 78% was noted at crack tip 1 of Hole-1 for a load ratio of 0.25 and a crack length of 38 mm. In contrast, Hole-13 in the Y-direction showed minimal impact on effective SIF under varying load ratios. The distribution of effective SIF with crack length at H1 was consistent for load ratios 1 and 0.75. However, for the bi-axial load ratios 0.5 and 0.25, the effective SIF distribution with crack length followed similar characteristics like Hole-4 and Hole-5 under equi-biaxial loading. Furthermore, the study explored the influence of shadow cracks at Hole-2 and Hole-3 on the effective SIF of the primary crack at Hole-1. It was found that Case-2 configuration was more effective in reducing SIF at primary cracks. References H. Vlieger. Results of uniaxial and biaxial tests on riveted fuse- lage lap joint specimens. Proceedings of FAA/NASA International Symposium of Advanced Structural Integrity Methods for Airframe Durability and Damage Tolerance, Hampton, VA 1994;4:911–30. Hithendra K, Prakash R V. A study of stress intensity factors in lozenge pattern of joints. ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), vol. 3, 2021, p. 1–10. Karakampalle H, Prakash R V. Effect of interference and location of the crack on the Stress Intensity Factor for the 3-2-1 Lozenge pattern riveted joint. Procedia Structural Integrity 2021;39:711–21. Liu J, Zhao A, Ke Z, Li Z, Bi Y. Investigation on the residual stresses and fatigue performance of riveted single strap butt joints. Materials 2020;13:1–19. Morishita M, Gotoh K, Anai Y, Tsumura S, Niwa T. Fatigue surface crack growth behavior in flat plate and out-of-plane gusset-welded joints under biaxial cyclic loads with different phases. Journal of Marine Science and Technology (Japan) 2021;26:655–72. Müller RP. An experimental and analytical investigation on the fatigue behaviour of fuselage riveted lap joints 1995:1–516. Pirondi A. Suitability of mixed-mode I/II assessment methods for implementation into the SINTAP procedure. Engineering Fracture Mechanics 2003;70:1597–609. Shi XQ, Zhang XR, Pang JHL. Determination of interface fracture toughness of adhesive joint subjected to mixed-mode loading using finite element method. International Journal of Adhesion and Adhesives 2006;26:249–60. Smith M. ABAQUS/Standard User’s Manual, Version 6.9. United States: Dassault Systèmes Simulia Corp; 2009. Suresh Kumar S, Ashwin Clement H, Karthik R. Mixed-Mode Stress Intensity Factor Determination of Riveted Lap Joints Used in Aircraft Fuselage Structures. Journal of Failure Analysis and Prevention 2017;17:780–7. Takahashi I, Takada A, Ushijima M and Akiyama S. Fatigue behaviour of a box-welded joint under biaxial cyclic loading: effects of biaxial load range ratio and cyclic compressive loads in the lateral direction. Fatigue \& Fracture of Engineering Materials \& Structures 2003;26:439–48.