Mesoscopic modeling of mechanical erosion for the ablation-erosion behavior of 3D C/C composites

Thermochemical ablation and mechanical erosion are common issues faced by carbon/carbon (C/C) composites in thermal protection systems. A mesoscopic mechanical erosion model is established to analyze the ablation-erosion behavior of 3D C/C composites. Firstly, a mesoscopic thermochemical ablation model describing the reaction and diffusion phenomenon of C/C composites is built and solved through numerical methods to obtain ablation morphologies. Then, the transient ablation morphologies are used as the geometric models for mechanical erosion analysis. Progressive damage method is employed for the damage and failure analysis of composites under mechanical erosion. A strategy introducing the mechanical erosion into numerical ablation calculation is proposed to investigate the ablation-erosion behavior. Moreover, the relationship between airflow shear and surface roughness is numerically calculated, which can be treated as a mechanical erosion criterion introduced into numerical ablation calculation. The effects of the reaction-diffusion ratio, component reactivity ratio, and critical pressure, on the surface recession, mass loss rate, and mechanical erosion factor are investigated. The results show that the mesoscopic mechanical erosion model can analyze the damage and failure behavior of erosion, and the ablation-erosion performance can well be characterized. This paper is beneficial to the evaluation and design of thermal protection system materials. [Figure not available: see fulltext.].