Experimental investigation on the hypervelocity impact damage behavior of polyimide film

Abstract

The damage behaviors of polyimide film hypervelocity impacted by the aluminum micro–flyer, accelerated by a laser driven flyer (LDF) system, are studied. The fracture morphologies of the impacted films are observed and measured by scanning electron microscopy (SEM). Aided with the technique of LDF and SEM, a parametric study on the HVI responses of polyimide film is implemented and the influence factors, including the film thickness, impact velocity, pre–stress level and flyer shape, are discussed. Results show that the damage behaviors of polyimide film are governed by the synergistic effect of the temperature and strain rate, and a three–zone fracture mechanism is proposed to explain the fracture phenomena. Furthermore, according to the experimental results, a series of damage parameters are defined to characterize the film's damage morphology, and then a comprehensive damage evaluation model is presented. Based on this model, a quantifiable damage grade system is established, in which the damage extent of the impacted film can be assessed under the different conditions.