Transient Force Measurement and Mechanism Analysis of Nanosecond Laser Ablation of Al/Ti Alloys Using Polyvinylidene Fluoride Sensors.

This study proposes a novel calibration method for polyvinylidene fluoride (PVDF) piezoelectric sensors based on electromagnetic force. The standard force source is obtained by calibrating the original force source of the inductor coil through an electronic balance. Transient force loading waveforms and peak values of PVDF piezoelectric sensors were obtained to analyze the mechanical effects of laser ablation on Al/Ti alloys. Transient force sensing using PVDF piezoelectric sensors exhibits a wide linear detection range (0.01-5.8 V) and high response values in response to changes in electrical signals. When irradiating Al/Ti alloy targets with different laser energies and spot sizes, the electrical signal intensity of PVDF piezoelectric sensors varies greatly, and the corresponding transient force peak value test results range from 0.01 to 8.5 N. This excellent transient mechanical sensing performance can be attributed to the high laser power density, efficient laser energy utilization, and the physical properties of the target material. COMSOL Multiphysics simulation results confirmed that the temperature and ablation center position of the surface of the target material undergo significant changes after being irradiated with different laser energies and spots. The simulation results are consistent with the experimental results. This research indicates that transient force measurements based on PVDF piezoelectric sensors have broad prospects in high-performance optical laser propulsion applications.