Investigation of the spall strength of graphite using nano- and picosecond laser pulses

Numerical Simulations of Laser-Induced Shock Experiments on Graphite

“…In this sense, data from experiments in compression are easily available in the literature. However, the literature concerning the spall tensile behaviour of highly porous materials such as graphite is limited [26,50]. For this reason, the research work developed at the CEA research institute [51][52][53][54][55] is clearly relevant.…”

“…For this reason, one of the objectives of the Work Package 17 of the ARIES project is to reach energy densities beyond those reachable at the HiRadMat through high-energy laser beams. In spite of the differences between laser and particle beams, the effects on the impacted materials have proven to be comparable [26]. At least locally, the beam coming from a laser generates the same energy deposition of a particle beam, hence inducing a quasi-instantaneous heating and eventually a change of phase of the lightened surface.…”

“…In view of this challenging experimental campaign, the present work has the aim of investigating the behaviour of graphite impacted by highly energetic laser beams through an extensive use of numerical simulations. Even though most of the experimental works concerning laser-induced shockwaves have been applied to metals, some efforts have also been made to characterise graphite [26,28]. Hence, taking into account the laser shots fired at the CEA research centre as the benchmark, some numerical simulations have been developed with the objective of extrapolating paramount information regarding the response of this porous material when impacted by laser beams.…”

Study of extreme states of matter at high energy densities and high strain rates with powerful lasers

“…At that time, for this purpose, the laser facilities "Kamerton" and "Sirius" were used. By now, with the laser "Kamerton-T", spallation phenomena are studied in aluminum, tantalum, copper, tungsten, palladium, lead, silicon, graphite, synthetic diamond and polymethylmethacrylate [16,17,19,[21][22][23][24][25][26][27][28][29][30]. Photographs of rear sides of the targets of some materials after laser action are shown in figure 4.…”

“…The results of investigation about the spall strength upon the strain rate for diamond [26][27][28] and graphite [29,30] are presented in figure 7. In experiments with synthetic diamonds, the value 16.5 sp σ GPa at a strain rate of 70 μs −1 is achieved, which is 24% of the theoretical evaluation of the ultimate strength 69.5 GPa according to the equation of state [43].…”