https://sam.ensam.eu:443 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Mon, 09 Mar 2026 03:15:38 GMT 2026-03-09T03:15:38Z http://hdl.handle.net/10985/16035 Dynamic fragmentation of graphite under laser-driven shocks: Identification of four damage regimes SEISSON, Gabriel; PRUDHOMME, Gabriel; FRUGIER, Pierre Antoine; HÉBERT, David; LESCOUTE, Emilien; SOLLIER, Arnaud; VIDEAU, Laurent; MERCIER, Patrick; BOUSTIE, Michel; BERTHE, Laurent This study presents the results of a large experimental campaign conducted on the Luli2000 laser facility. Thin targets of a commercial grade of porous graphite were submitted to high-power laser-driven shocks leading to their fragmentation. Many diagnostics were used such as high-speed time- and space-resolved imaging systems (shadowgraphy and photography), laser velocimetry (PDV and VISAR), debris collection and post-mortem X-ray tomography. They provided the loading levels into the targets, the spall strength of the material, the shape and size of debris and the localization of the subsurface cracks. The crossed data reduction of all the records showed their reliability and allowed to get a better insight into the damage phenomena at play in graphite. Thereby, four damage regimes, ranked according to their severity and loading level, were identified. It confirms that laser shocks are very complementary to classical impact tests (plates and spheres) since they ally two-dimensional loadings to the possibility of using both, in-situ and post-mortem diagnostics. Finally, the campaign shall be able to provide large and consistent data to develop and adjust reliable models for shock wave propagation and damage into porous graphite. Fri, 01 Jan 2016 00:00:00 GMT http://hdl.handle.net/10985/16035 2016-01-01T00:00:00Z SEISSON, Gabriel PRUDHOMME, Gabriel FRUGIER, Pierre Antoine HÉBERT, David LESCOUTE, Emilien SOLLIER, Arnaud VIDEAU, Laurent MERCIER, Patrick BOUSTIE, Michel BERTHE, Laurent This study presents the results of a large experimental campaign conducted on the Luli2000 laser facility. Thin targets of a commercial grade of porous graphite were submitted to high-power laser-driven shocks leading to their fragmentation. Many diagnostics were used such as high-speed time- and space-resolved imaging systems (shadowgraphy and photography), laser velocimetry (PDV and VISAR), debris collection and post-mortem X-ray tomography. They provided the loading levels into the targets, the spall strength of the material, the shape and size of debris and the localization of the subsurface cracks. The crossed data reduction of all the records showed their reliability and allowed to get a better insight into the damage phenomena at play in graphite. Thereby, four damage regimes, ranked according to their severity and loading level, were identified. It confirms that laser shocks are very complementary to classical impact tests (plates and spheres) since they ally two-dimensional loadings to the possibility of using both, in-situ and post-mortem diagnostics. Finally, the campaign shall be able to provide large and consistent data to develop and adjust reliable models for shock wave propagation and damage into porous graphite. http://hdl.handle.net/10985/9902 Experimental and numerical investigations of shock and shear wave propagation induced by femtosecond laser irradiation in epoxy resins ECAULT, Romain; BERTHE, Laurent; TOUCHARD, Fabienne; BOUSTIE, Michel; LESCOUTE, Emilien; SOLLIER, Arnaud; VOILLAUME, Hubert In this work, original shock experiments are presented. Laser-induced shock and shear wave propagations have been observed in an epoxy resin, in the case of femtosecond laser irradiation. A specific time-resolved shadowgraphy setup has been developed using the photoelasticimetry principle to enhance the shear wave observation. Shear waves have been observed in epoxy resin after laser irradiation. Their propagation has been quantified in comparison with the main shock propagation. A discussion, hinging on numerical results, is finally given to improve understanding of the phenomenon. Thu, 01 Jan 2015 00:00:00 GMT http://hdl.handle.net/10985/9902 2015-01-01T00:00:00Z ECAULT, Romain BERTHE, Laurent TOUCHARD, Fabienne BOUSTIE, Michel LESCOUTE, Emilien SOLLIER, Arnaud VOILLAUME, Hubert In this work, original shock experiments are presented. Laser-induced shock and shear wave propagations have been observed in an epoxy resin, in the case of femtosecond laser irradiation. A specific time-resolved shadowgraphy setup has been developed using the photoelasticimetry principle to enhance the shear wave observation. Shear waves have been observed in epoxy resin after laser irradiation. Their propagation has been quantified in comparison with the main shock propagation. A discussion, hinging on numerical results, is finally given to improve understanding of the phenomenon. http://hdl.handle.net/10985/8061 Observation of the shock wave propagation induced by a high-power laser irradiation into an epoxy material ESCAULT, Romain; BERTHE, Laurent; BOUSTIE, Michel; TOUCHARD, Fabienne; LESCOUTE, Emilien; SOLLIER, Arnaud; MERCIER, Patrick; BERNIER, Jacky The propagation of laser-induced shock waves in a transparent epoxy sample is investigated by optical shadowgraphy. The shock waves are generated by a focused laser (3 ns pulse duration—1.2 to 3.4TWcm−2) producing pressure from 44 to 98.9 GPa. It is observed that the shock wave and the release wave created by the shock reverberation at the rear face are both followed by a dark zone in the pictures. This corresponds to the creation of a tensile zone resulting from the crossing on the loading axis of the release waves coming from the edge of the impact area (2D effects). After the laser shock experiment, the residual stresses in the targets are identified and quantified through a photoelasticimetry analysis of the recovered samples. This work results in a new set of original data which can be directly used to validate numerical models implemented to reproduce the behaviour of epoxy under extreme strain rate loading. The residual stresses observed prove that the high-pressure shocks can modify the pure epoxy properties, which could have an influence on the use made of these materials. Wed, 01 Jan 2014 00:00:00 GMT http://hdl.handle.net/10985/8061 2014-01-01T00:00:00Z ESCAULT, Romain BERTHE, Laurent BOUSTIE, Michel TOUCHARD, Fabienne LESCOUTE, Emilien SOLLIER, Arnaud MERCIER, Patrick BERNIER, Jacky The propagation of laser-induced shock waves in a transparent epoxy sample is investigated by optical shadowgraphy. The shock waves are generated by a focused laser (3 ns pulse duration—1.2 to 3.4TWcm−2) producing pressure from 44 to 98.9 GPa. It is observed that the shock wave and the release wave created by the shock reverberation at the rear face are both followed by a dark zone in the pictures. This corresponds to the creation of a tensile zone resulting from the crossing on the loading axis of the release waves coming from the edge of the impact area (2D effects). After the laser shock experiment, the residual stresses in the targets are identified and quantified through a photoelasticimetry analysis of the recovered samples. This work results in a new set of original data which can be directly used to validate numerical models implemented to reproduce the behaviour of epoxy under extreme strain rate loading. The residual stresses observed prove that the high-pressure shocks can modify the pure epoxy properties, which could have an influence on the use made of these materials.