16 Figure 4. Energy balance vs time (Ue= elastic energy, Uk= kinetic energy, Ud= dissipated energy (a) Uniaxial compression (Emax=4888Nm), (b) Three point bending (Emax=0.65Nm). Figure 5. (a) Final rupture configuration of concrete specimen subjected to uniaxial compression (Carpinteri et al., 2009) and (b) collapse configuration predicted by DEM model after peak load is reached (only nodal masses are shown). The white rectangle indicates the position of the sensor. Finally Figure 10 presents plots of the logarithm of the number of events larger than given amplitudes vs. the logarithms of the amplitudes for the DEM simulations of the compression test (left plot) and of the three points bending test (right plot). Notice that the shape of these curves are similar to the typical curve for seismic data shown in Figure 3, which according to Scholz (2002), from the size distribution of subfaults, may be expected to present slopes given by b1= ⅔ and b2= 1. While similar values are usually found in actual seismic records for specific faults or seismic regions, they differ from some of the laboratory or numerical simulations results for small samples discussed herein. (a) (b) Figure 6. (a) Detail of the exerimental rupture configuration of the specimen subjected to Three Point Bending (Carpinteri et al., 2009a) (b) Numerical rupture configuration according to DEM (only damaged bars are plotted). The small gray rectangle indicates the position of the sensor. UK Ud Ue Ue UK Ud t* t* (a)
RkJQdWJsaXNoZXIy MjM0NDE=