PSI - Issue 71

Ajay Patel et al. / Procedia Structural Integrity 71 (2025) 196–202

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2. Methodology 2.1 Experimental Setup

This approach offers a thorough method for examining mild steel corrosion using both experiment and FE simulation. It incorporates sensor-based damage monitoring to evaluate material deterioration over time using admittance signatures and FEM. The process began with the selection and preparation of mild steel specimens. A standardised mild steel coupon measuring (76.2 mm x 12.7 mm x 1.5875 mm) was chosen for the experiment, in accordance with NACE/ASTM standards, the properties are listed in table 1 and the mild steel coupon can be seen in Fig.1(a) immersed in NaCl solution on first and last day. The surface of the steel coupon was thoroughly cleaned and degreased using suitable agents, such as acetone, to ensure accurate results. The prepared mild steel coupon was then immersed in a 3.5% sodium chloride (NaCl) solution to simulate a corrosive saline environment. The exposure lasted for 40 days to observe the corrosion behaviour over time. Initially, the mass of the mild steel coupon was recorded by using a high precision analytical balance and condition of specimen over 40 days can be seen in Fig.1(b). Table 1. Properties of mild steel coupon and gravimetric mass loss over the time

Properties

Mild Steel

Days

Mass (grams) Variation of mass w.r.t. day 1 mass (grams)

Modulus of elasticity (E)

200 GPa

1

11.6484 11.5579 11.4891 11.4105

-

10 20 30

0.0905 0.1593 0.2379

Poisson ratio (ν)

0.3

Density (ρ)

7860 kg/m 3

40

11.3312

0.3172

Every 10 days, the coupon was removed from the NaCl solution, carefully dried to eliminate surface moisture, and weighed to determine the mass loss, as shown in Table 1. The mass loss (∆m) was calculated by comparing the initial mass with measurements taken at each interval.

(a) (b) Fig. 1. (a) Specimen in the 3.5% NaCl solution on initial and the final day, and (b) Specimen's condition recorded on days 1, 10, 20, 30 and 40

2.2 Finite Element Modelling (FEM) and Coupled Field Analysis (CFA)