Influence of elastomer film thickness and particle size on laser-induced microparticle launch

Laser-induced microparticle impact testing (LIPIT) provides an effective experimental method for revealing the ultrahigh strain-rate dynamic response of materials by launching a single microparticle through laser-induced film expansion to impact a target material. Understanding the coupling effects of laser ablation and the dynamic responses of both the films and microparticles during the launch process in LIPIT is essential for achieving higher launch velocity of the microparticle. In this study, the influences of elastomer film thickness and microparticle diameter on the launch process are investigated by numerical simulations. The results show that the laser-induced plasma pressure experiences a sudden increase in the launch system with a thin or without elastomer film due to the inertial effect of microparticle and the reflection of laser-induced shock waves at the microparticle–film interface. As the elastomer film thickness increases, the onset time of the sudden increase in pressure delays and the amplitude of the peak pressure decreases. When the elastomer film thickness exceeds about 10 μm, the influence of elastomer film thickness is negligible. Additionally, the microparticle launch velocity decreases with increasing elastomer film thickness. In a launch system without an elastomer film, increasing the microparticle diameter leads to a greater amplitude of the sudden increase in plasma pressure, resulting in a higher launch velocity. However, when the microparticle diameter exceeds 9.2 μm, the launch velocity begins to decrease with increasing diameter. This study discloses the coupling effects during the microparticle launch process in LIPIT and provides insights into experimental design and optimization of the LIPIT system.