PSI - Issue 33

2

Author name / Structural Integrity Procedia 00 (2019) 000 – 000

Sergey Uvarov et al. / Procedia Structural Integrity 33 (2021) 465–468

466

1.1. Specimen and preparation Specimens were cut from thick plate made from commercially available prepreg CM-Preg F-T27 200/1250 CP0041 45 bought at carbocarbo.ru. Plate was cured according the procedure provided by producer but curing time was set 2 times longer because of the thickness. Thickness of the plate was 28 mm allows us to cut cubic shaped specimens with the angle between layer and load surface in the range 0-45 0 (Fig. 1).

Fig. 1. Specimens cut from the thick plate.

Dimension of the specimen was 16x16x16mm in order to fit the surface of the 25mm Split-Hopkinson pressure bar (SPHB).

1.2. Testing procedure Bi-axiality of the loading conditions were due to the fact that the CFRP laminate is a strong anisotropic material and when angle between layer orientation and load direction differs from 0 or 90 0 the strain main axis does not parallel to load direction (Fig. 2). The friction between load surface of the specimen and testing machine provides the friction force. In this case we have the combination of shear Fs = F ∗ cos . and compression Fc = F ∗ sin force acting on the interlaminar surface.

Fig. 2. Deformation of the specimen with 45 0 layer orientation and acting force decomposition. .

With the DIC we have measured the uniformity of the strain at these loading conditions. For 45 0 specimen main strain axis direction was 45±5 0 . Main angle variation comes from DIC errors due to low level of strain (Fig.3).