Issue 39

J. Klon et alii, Frattura ed Integrità Strutturale, 39 (2017) 17-28; DOI: 10.3221/IGF-ESIS.39.03 21 Figure 3 : Plots of work of fracture due to quasi-brittle fracture W f ( a ) and brittle effective crack length propagation W f,b ( a ) (top left), their subtraction resulting in plot of cumulative energy dissipated in FPZ W f,fpz ( a ) (top right), and plot of FPZ envelope (bottom). A PPLICATION OF THE MODEL – EVALUATION OF EXPERIMENTAL DATA Experiment by Hoover et al. n the comprehensive experimental campaign reported in [24], four beam sizes of widths W = 500, 215, 93 and 40 mm (marked as A to D), with three relative notch lengths  0 = 0.075, 0.15, and 0.3, were tested. Ratio of the smallest and the largest tested specimen is remarkable, namely 1:12.5. Several samples were tested for each W and  0 , for details see [24]. P–d diagrams were not measured properly in many cases; therefore, reconstructions of these diagrams based on the correctly recorded P–CMOD curves ( CMOD stands for crack mouth opening displacement) were conducted with the help of numerical simulations in ATENA FEM programme [29] (parameters of the fracture-plastic material model used for concrete were identified according to the recorded P−CMOD diagrams) and subsequent data corrections were performed (details see in [30]). Nominal dimensions of the test specimen are shown in Tab. 1. Specimen Width W [mm] Crack length a 0 [mm] Rel. crack length  0 = a 0 /W [-] Length L [mm] Span S [mm] Breadth B [mm] Maximum FPZ width t max [mm] D040 D 40 3 0.075 96 87.04 40 42 6 0.15 42 12 0.3 58 D093 C 93 6.98 0.075 223.2 209 40 77 13.95 0.15 74 27.9 0.3 70 D215 B 215 16.13 0.075 516 467.84 40 122 32.25 0.15 111 64.5 0.3 143 D500 A 500 37.5 0.075 1200 1088 40 390 75 0.15 350 150 0.3 254 Table 1 : Nominal dimensions of specimens from experiment [24]; estimated maximal widths of FPZ are shown in the right column. I