PSI - Issue 64

1922 Rosario Lombardi et al. / Procedia Structural Integrity 64 (2024) 1919–1926 Rosario Lombardi et al. / Structural Integrity Procedia 00 (2019) 000 – 000 • is the linear density, in grams per kilometer (the subscript coincides with “dr” if it is a dried sample, “und” if it is an undried sample); • is the recorded mass of the specimen, in grams; • is the recorded length of the specimen, in meters 2.3.3. Ideal cross section and absorption In addition to what was previously described, all the data obtained were used to determine other two parameters: the ideal cross-sectional area of the yarn, and the absorption capacity of the impregnated fabric. Cross-section For estimating the cross-sectional area of the yarn an ideal cylinder geometry is assumed. The reference relationship in this case coincides with the ratio between the linear density and the density of the impregnated fabric: = 10 3 ∗ [ 2 ] (2.2) where: • is the ideal area of the specimen, in mm 2 ; • is the mean linear density of the yarn, in g/km; • is the mean density of the yarn, in g/cm 3 . Specifically, the linear density value is the one calculated for the dried samples. Absorption capacity The weighing values obtained in the previous procedures were also used to calculate the absorption capacity of the different impregnated fabrics. This was done by subtracting its dry weight from the weight of the single sample in SSD condition, and then dividing this difference by the weight of the dried sample. The value thus obtained is • is the absorption of the specimen, in %; • ( ) is the weight of the sample in SSD conditions, in air, expressed in g; • is the recorded mass of the specimen, in grams. Furthermore, using the same input parameters, the absorption was also calculated in milligrams per centimeter. Thus, it was also possible to observe the actual quantity of water absorbed by the fabric per unit length: = ( ) − [ / ] (2.4) where: • is the length of the specimen, in cm; 2.4. Mechanical characterization 2.4.1. Tensile Tests The tests conducted for the mechanical characterization of the impregnated yarns coincide with the tensile tests executed in accordance with the reference standard BS ISO 3341:2000. The main characteristics of the tensile are: gauge length of 500 mm; elongation speed of 200 mm/min. Ten samples were tested for each type of fibers and amount of impregnation considered herein. 4 considered as a percentage value: = ( ) − ∗100 where: [%] (2.3)