PSI - Issue 60

A.B. Penurkar et al. / Procedia Structural Integrity 60 (2024) 355–363 A.B. Penurkar/ Structural Integrity Procedia 00 (2023) 000 – 000

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Table 1: Typical chemical composition of sodium silicate glass used for the test. S.No. Elements Wt % 1 Silica 73 2 Sodium Carbonate 15 3 Calcium Carbonate 11 4 Boron 0.68 5 Iron 0.19 6 Zinc 0.029 7 Titanium 0.068

Experiments were carried out using universal testing machine at creep testing Lab., RSD, BARC as shown in Fig. 3. The three point bend setup used for the tests is shown in Fig. 3(a). The indenter and attachment is made up of precipitate hardened (PH) steel in order to avoid their deformation during loading of the specimen. The indenter has a radius of 3 mm and depth of around 15 mm. It should be noted that proper line contact between the indenter and glass specimen should occur before the test is started. Also, the machine alignment is checked properly. A batch of 26 and 25 glass slides of thickness 4 mm and 8mm respectively are tested to obtain the scatter in the fracture stress for a particular thickness. These single batch of slides were subjected to three point bending experiments under displacement control mode with the loading rate of 0.05 mm/min controlled through a computer software. There should be no load on the specimen while placing the specimen on the attachment. Lower crosshead of the machine can move upward or downward due to which the specimen is loaded. Load cell is used for determination of the fracture load of the glass specimen. The maximum load at which the specimen gets broken is noted. The glass breaks into two parts if proper alignment of the top and bottom fixture is carried out. The specimen before and after the test is shown in Fig. 2(c). Load, displacement, stress and strain value are recorded at a user-defined time intervals and written to a text file. Post processing of raw data is carried out for evaluating the fracture stress of the glass material.

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(c) Fig. 2: (a) Glass plate (300x300 mm) used for fabrication of specimen (b) Design details of glass specimen used for TPB tests (c) Specimen before and after test.