PSI - Issue 82

Jet Best et al. / Procedia Structural Integrity 82 (2026) 98–106

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J. Best et al. / Structural Integrity Procedia 00 (2026) 000–000

to one side of the samples and graduated to help visualise crack propagation. The progress of the crack was monitored using a digital camera synchronised with load and displacement measurements. In each case, five samples were tested at a crosshead displacement rate of 2 mm/min. Mode I fracture toughness, denoted as 'G IC ', was calculated as: !" = & ' (#)$*%| , | ) (1) where P represents applied load, and δ represents crosshead displacement. The sample width is denoted by b , while the total delamination length, which consists of the initial delamination length a 0 and the measured increments in delamination length, is represented by a . The large displacement correction, denoted as F , was calculated following the standard. SEM analysis of fracture surfaces was conducted using a Hitachi TM4000 Tabletop microscope. The SEM analysis was conducted at an accelerating voltage of 15 kV. 3. Results & Discussion 3.1. Epoxy characterization Easy Composites IN2 resin samples were produced using the following curing schemes: [1] 120 ° C for 3h

[2] 120 ° C for 3h followed by 180 ° C for 1h [3] 25 ° C for 24h followed by 100 ° C for 3h

Fig. 1. DMA Analysis of Easy Composites IN2 resin storage modulus and glass transition temperature under varied curing regimes.