Study of simulation and experimental on the damage of stray light absorbing function films induced by nanosecond laser

Abstract

The functional film based on alumina/silica can greatly improve the absorptivity of stray light and effectively avoid the formation of high-order ghost light after multiple reflection of stray light in high-energy laser system, which can lead to material splashing and irreversible contamination of the high-energy laser system. This process is currently difficult to dynamically capture through experiments. Therefore, it is important and challenging to accurately analyze the multiple physical fields and damage evolution involved in the stray light action process by combining experiment and simulation and explore the response relationship between the action effect and laser parameters. In this paper, the mechanical properties parameters of the films were firstly determined by experiments combined with the inverse finite element method. The process of systemic stray laser with four typical energy densities irradiating on stray-light-absorbing functional films prepared by anodic oxidation and electrolysis was analyzed. We developed a dynamic thermal-mechanical-damage direct coupling model through ABAQUS and its secondary development, considering the temperature dependence of the thermodynamic and optical parameters of the three materials, the damage characteristics of brittle materials, and the adaptive progressive loading of the surface heat source boundary. Then, the multi physical fields and damage evolution with different material constitutive models were compared and analyzed. Compared with the JH-2 constitutive, bilinear constitutive is more suitable to describe the thermo-mechanical evolution of ceramic oxide functional films in the simulation of laser-irradiating process. The response relationship between damage and pulse number and the damage mechanism were analyzed from the perspective of experiment, which is in good agreement with the simulation results. The damage of functional films is not sensitive to the number of pulses but the damage is more sensitive to the initial defect, which can induce and enhance.