3D Reinforced Composites for Improved Impact Resistance in Spacesuits

This proposal seeks to develop an advanced material solution for the hard upper torso (HUT) component with improvements in impact resistance. The current HUT is a 2D laminate which is more susceptible to delamination between plies under impact conditions. Materials Research & Design is proposing an investigation of 3D braided/woven composites for improved impact strength. The overall objective of this Phase I program is to demonstrate the ability to improve interlaminar shear strength of an S-2 / epoxy composite material with across-ply reinforcement to improve impact resistance. Phase I will focus on the fabrication and characterization of at least one material system consisting of 3D woven S-2 fibers with an epoxy matrix. Characterization of this material will consist of flexure testing and asymmetric four-point bend testing to derive in-plane tensile modulus and strength and interlaminar shear strength. These measured material properties will be used to develop a material model to estimate properties for other woven/braided architectures. These additional material systems, along with the fabricated material will be simulated in finite element models, simulating the performance under impact loading. Results from these cases will be compared for all material architectures to determine which has the greatest potential to survive operational impact scenarios. The architectures evaluated will be ranked by their potential for further evaluation in Phase II. The values for comparison include estimated/measured strengths, mass savings compared to the baseline material, and estimated performance based on the impact loading finite element analysis. Phase II of the program will focus on the maturation of the candidate materials down-selected from the Phase I results. It will include additional testing of candidate materials, specifically impact and permeability testing. Phase II will conclude with a full or sub-scale prototype fabricated of the final material.