Damage Threshold of Borosilicate Glass Under Plate Impact

Abstract

Symmetric plate-impact tests of borosilicate glass projectiles into borosilicate glass targets were performed at stress levels from 0.7 to 2 GPa (impact velocities from 116 to 351 m/s). As far as the authors know this range of velocities has not been explored in the literature previously. The tests used an ultra-high-speed camera to record shock and failure propagation. The velocity of the back of the target was also recorded with a photon Doppler velocimeter (PDV). The images clearly show the shock wave and its propagation at the speed expected. The reflected tensile wave is also apparent. What the authors interpret as the failure wave/front is clearly observed and appears at stress levels of 0.8 GPa (velocities as low as 130 m/s). The images apparently show failure nucleation sites that trail the shock wave. These seem to be closer to the shock wave for higher speeds. A possibility is that the defects open faster at higher impact velocity while at lower velocities they are still present but remain undetected. Interestingly, even though the failure wave is clearly seen, the PDV never detected the expected recompression wave. The reason might be that at these low impact velocities the recompression wave is too small to be seen and is lost in the noise. This, in the past, may have confused researchers by thinking that the failure wave was not present at these low impact velocities. This work also presents a new way to interpret the signals from the PDV. By letting part of the signal travel through the target and reflect on the impact side, it is possible to see the PDV signal decrease in intensity with time. This would be consistent with having damage in the interior of the specimen, something not straightforward to confirm through just high-speed photography.

Mechanical Response of Borosilicate and Soda-Lime Glass Under Dynamic Triaxial Compression

“…The experiments reported in this paper are performed in the strain-rate range that are typically achieved in a Kolsky bar set up (*10 3 s -1 ). To explore the mechanical response of glass under impact loading conditions, experiments at higher strain rates and higher pressure, such as those recently performed by Chocron et al [14], are also desired to develop insights to the glass failure over a wider range of loading conditions.…”

“…Experimental results at higher strain rates are still very limited, e,g., Chocron et al [14], to compare the results over a very wide range of strain rates. However, there have been more studies on the rate and confinement effects on brittle materials such as ceramics.…”

Celebrating 75 Years of the Society for Experimental Mechanics and the Study of Dynamic Behavior of Materials

“…The journal is highly international, publishing experimental and theoretical studies of metals [57], polymers [58], glasses [59], composites [60], granular materials [61], explosives [62], biological materials [63], geological materials [64], phase transitions [65], and structural response [66]. The journal includes application and development of techniques including split Hopkinson pressure bar/Kolsky bar [67], plate impact with light gas guns and powder guns [68], Taylor Anvil [69], Dynamic-TensileExtrusion [70], spectroscopy-and pyrometry-based shock temperature measurements [71], optical and X-ray imaging methods [72], interferometry and velocimetry techniques [73], dynamic fracture [74], laser based dynamic drivers [75], penetration and ballistics [76], equation of state [77], and spall failure [78].…”

An improved computational constitutive model for glass

“…The general approach to determine constants was presented by Holmquist & Johnson [1]. For Borofloat 33, all of the constants are determined directly from data in the literature [7,8,[10][11][12], except for the damage and failed-strength constants which are inferred from dwell and penetration data [13,14]. Time-dependent softening is not used because it has been shown to inhibit the propagation of failure [11,15], in disagreement with experimental data.…”