PSI - Issue 71

Abdul Khader Jilani Shaik et al. / Procedia Structural Integrity 71 (2025) 42–49

48

=√ 5 (a) = .

=

. ⋅ +( ) 5 (c)

⋅ +( ) 5(b)

(5)

Boundary correction factor, =( + ( ) + ( ) )

(6)

= − ( ) ( . − ) = + ( . )

+ (( ))

(7)

(8)

= + . + ⋅ − ⋅ + . + . = + . ( − ) ( − )

(9)

(10)

ΔS = 3.273 MPa √ ΔK I2 =6.462MPa √ ΔK I1 =6.32MPa √

Estimated SIF through the above Analytical expressions Estimated SIF through FEM = 6.467 MPa √ (max) Percentage of error = 2.27%

( ) = (2 + ) [0.886 + 4.64 ( ) − 13.32 ( ) 2 + 14.72 ( ) 3 −5.6( ) 4 ] (1− ) 3 2

(11)

Table 5 Comparison of Stress Intensity Factor (SIF) of ASTM C(T) Specimen. Load (in N) SIF (MPa √ ) as per FEM Min Max

SIF (analytical) asper ( ) of ASTM

Unit Load(1N)

0.00221 90.254

0.00263

0.00238

40760

107.2

96.98

9 Through-the-thickness Crack Growth Analysis on Lug The investigation focuses on crack growth in the lug due to fatigue. A crack of 1.55 mm was initiated on the lug hole surface, perpendicular to the load direction, stemming from a high-stress riser in the bush. We employed the Finite Element Method (FEM) for analysis, applying Paris' Law to understand fatigue crack propagation. The study begins with crack growth in the bush and then examines the lug's 6.35 mm thickness under increasing loads from 9.5 kN to 60 kN during each fatigue cycle. We calculated the cycles required for the crack to grow from 0.6 mm to 6.5 mm. Fig. 9 shows the relationship between crack growth and the Stress Intensity Factor (SIF) and the growth of single and dual cracks over cycles are presented in Fig. 10.

Fig. 9 Variation of SIF w.r.t Crack length.

Fig. 10 Crack extension Vs No of Cycles.