Multi-layer insulation material models suitable for hypervelocity impact simulations

MLI (multi-layer insulation) is present in many spacecraft missions and typically consists of multiple layers of aluminized Kapton separated by fine gauze. It has been observed, depending on the type and position within the structure, that MLI can influence the ballistic performance of panels under hypervelocity impact (HVI) despite being extremely lightweight. Due to the very thin nature of the foils, <10 μm, it is often considered too computationally expensive to explicitly include such materials in HVI simulations of typical structures used in space. Accurate resolution of the foils would require a prohibitive number of elements. This paper reports on the development of a discrete modelling approach that efficiently facilitates the inclusion of such materials and allows for each layer of the MLI to be explicitly represented in the numerical model. Mesomechanical simulations of planar plate impact experiments (PPI) and an HVI event on MLI are presented where each layer of the MLI is explicitly represented with a number of elements through the thickness. The results of these models are then compared with the developed discrete approach suitable for including in larger scale simulations of impacts on real space structures. The current study applies previously developed material models to structural materials such as Carbon Fiber Reinforced Plastics (CFRP). This paper further describes simulation of an HVI event on a CFRP-Aluminum/honeycomb structure at oblique incidence, thereby illustrating that the developed approach for modelling MLI provides a practical method for the inclusion of such materials in full-scale simulations.