PSI - Issue 71

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

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2.1. Materials and Methodology The lug is made of Aluminum Alloy 2024-T4, while the bush and pin are constructed from AISI 4340 Steel. All components exhibit nonlinear elastic-plastic behavior for stress analysis. The analysis was conducted under a uniaxial tensile load on the pin. Contact pairs simulate interference between the lug-bush and clearance between the bush-pin, using the Augmented Lagrange element formulation for asymmetric contact behavior.

Fig. 2 Solid Model of Lug Bush Pin Joint.

Fig. 3 Meshed Model of Lug Bush Pin Joint.

These materials demonstrate nonlinear elastic-plastic behavior and have been selected for stress analysis. The analysis of the Lug-Bush-Pin assembly under uniaxial tensile load accurately models interference and clearance contact conditions between the interfacing pairs, utilizing asymmetric contact behavior through Augmented Lagrange Element formulation. The parameters for strain-life are computed and introduced into the Numerical Simulation Model following the guidelines in Laghzale et al. (2016), to facilitate fatigue life estimation based on the strain-life approach. The specific strain-life parameters are documented in Table 2 for comprehensive reference. The numerical simulation model has been meticulously built using the licensed ANSYS Workbench Mechanical 2023R1. The Lug Bush Pin assembly, created in PTC's Creo Parametric, has been intricately meshed using the innovative TETRAGONAL SOLID 187 element. With its advanced capabilities including plasticity, hyper-elasticity, creep, stress stiffening, large deflection, and large strain, this element is specifically tailored for fatigue crack growth studies.

Table 2 Material Properties of Lug Joint Components [6]. Description

Lug

Bush/Pin

Material

Aluminum Alloy

Stainless Steel

Material specification

2024-T4

AISI 4340

Young's Modulus, E (in MPa)

70000 0.33 2780 28000

193060 0.29 7850 80000 1179 1241 1579 -0.101 1655 1923 0.591 -0.65

Poisson's Ratio, υ Density (Kg/m 3 ) Shear modulus (MPa) Yield Strength (MPa)

303 476 807 634 737

Ultimate Tensile strength σ b (MPa) Strength Coefficient, K (MPa) Strength Exponent (b) Fracture Strength, σ f (MPa) Ductility coefficient ( ϵ f ') Ductility exponent (c) Fatigue Strength Coefficient σ f '(MPa) Strength Coefficient (K’) (MPa) Strain Hardening exponent (n') Tangent Modulus (MPa) Paris law constant C, mm/cycle Paris law constant m, mm/cycle 2.2. Mesh Convergence Study

-0.078

0.301 -0.73

764 0.08 560

889 0.14 1700 3.09 1.958

6.187x10 -12

3 x10 -10

A mesh convergence study was performed to optimize the analysis by varying the number of elements around the bushing and in both the bushing and the pin. The results showed that using 129,692 elements and 190,120 nodes provides the best balance of computational efficiency and accuracy. This configuration achieves a 1.45% difference in equivalent stress compared to the finest mesh under consideration, indicating satisfactory accuracy.