Issue 35

O. Demir et alii, Frattura ed Integrità Strutturale, 35 (2016) 330-339; DOI: 10.3221/IGF-ESIS.35.38 338 Results of T-Specimen Experiments In this subsection, results from mixed mode fracture analyses of a new type of mixed mod-I/II specimen, T-specimen, that has smaller dimensions compared to the regular CTS specimen are presented. In Fig. 15, front and overall views of the T-specimen and its loading devices are shown. Detailed fracture analyses are performed using different dimensions under different loading cases to provide small scale yielding conditions under LEFM rules. Crack tip plastic zone sizes of all specimens are measured after the fracture analyses to make sure that plastic zone size is smaller than 1/50 of the specimen thickness for all loading cases. (a) (b) Figure 15 : The front and overall views of (a) T-specimen, (b) Loading device of the specimen. Overall views of the mixed mode-I/II test assembly solid model and of T-specimen along with experimental set-up for 45° loading angle are given in Fig. 16. Mixed mode loading clevises are designed such that for all loading angles, the loading axis to pass through the mid-point of a line that can be drawn between the inner two pins. Figure 16 : Overall and exploded views of the T-specimen test assembly and experimental set-up (loading angle 45°). Tab. 3 summarizes experimental results from 25 mm-thick T-specimen tests. It can be seen from the experimental results of CTS and T specimens that loading requirements of 25 mm thick T specimens under all loading cases are lower than 10 mm thick CTS specimens. Specimen No Specimen Type Loading Angle (°) Thickness (mm) Crack Length (mm) Pre-crack Load (kN) EXPERIMENTAL Critical Load (kN) Crack Deflection Angle (°) T-LT-01-251214-01 T 0 24.87 26.03 10.5 19.60 0.00 T-LT-01-180115-12 T 15 25.00 26.93 10.5 19.80 -11.73 T-LT-01-180115-13 T 15 24.98 26.34 10.5 19.70 -9.34 T-LT-01-180115-14 T 30 24.98 26.21 10.5 23.07 -21.95 T-LT-01-180115-15 T 30 25.00 26.90 10.5 20.64 -18.07 T-LT-01-251214-02 T 45 25.00 25.24 10.5 28.09 -26.26 T-LT-01-251214-03 T 45 25.01 25.46 10.5 29.21 -24.15 T-LT-01-251214-04 T 60 24.96 27.13 10.5 33.59 -33.69 T-LT-01-090215-18 T 60 25.00 26.58 10.5 34.76 -36.41 T-LT-01-180115-17 T 75 25.03 26.89 10.5 54.31 -50.19 T-LT-01-220215-22 T 75 24.96 26.70 10.5 55.04 -53.17 Table 3 : Experimental results of T-specimen. C ONCLUSIONS n this study, numerical and experimental analyses were performed using CTS specimen under different mixed mode- I/II loading. A new specimen type together with its loading device was also proposed that has smaller dimensions compared to the regular CTS specimen. Experimental results for the new specimen under different loading cases I