PSI - Issue 42

Fatih Kocatürk et al. / Procedia Structural Integrity 42 (2022) 1206–1214 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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3. Experimental validation studies of analytical formulation for maximum socket depth estimation The residual floor thickness between the end of the socket and the bottom of the head, , can be estimated by using Eq. (2) developed in Kocatürk et al. (2020). (2) where is the angle between horizontal axis and the line formed between end of the socket and tip of the socket, = ℎ + , = ℎ − are the parameters to simplify Eq. (2), and is the radius of the head. The MSD, , can be obtained by subtracting the residual floor thickness, , from the head height value, , as given in Eq. (3). The residual floor thickness, socket depth and head height were presented in Fig. 3. = − (3)

Fig. 2. (a) Bolt specimen produced by cold forging and (b) cross-section view.

Fig. 3. Cross-section view of the bolt with a SHD smaller than the SOD (Kocatürk et al., 2020).

Experimental tension tests were carried out to validate the analytical model given in Eq. (2). In experiments, bolt specimens were subjected to tension until their total failure by fracture. Tensile tests were performed on a Zwick Roel tension-compression testing machine with capacity of 300 kN. The FC height, w, formed in the broken specimens as a result of tensile tests, is shown in Fig. 4. The w values of the fractured specimens were measured using the profile projection device. The average of the three different w values obtained by turning each sample 120°