Improved Barriers to Turbine Engine Fragments: Interim Report III

Abstract

In support of the Federal Aviation Administration's Catastrophic Failure Prevention Program, SRI International has identified advanced materials and is developing shielding concepts to protect critical aircraft components from uncontained engine debris. Full-scale fragment impact tests on a commercial aircraft fuselage confirmed that barriers made from high-strength polymer fabrics in the fuselage wall could prevent penetration into the cabin. A computational capability is now being developed to enable efficient design of fabric fragment barriers. A mathematical model of woven fabric made from Zylon polybenzazoles (PBO), Kevlar, or Spectra was constructed using the data and observations from laboratory tests to measure yarn tensile and friction properties, quasi-static penetration tests to measure the evolution and phenomenology of fabric deformation and failure, and projectile impact tests to measure effects of fabric material, mesh density, boundary conditions (how a fabric is gripped), and projectile sharpness. The model was implemented in the LS-DYNA3D finite element code and used to simulate the failure behavior of yarns and fabrics under impact scenarios. The resulting insights are assisting barrier design. A simplified version of the computational model is being developed to enhance its usefulness to the commercial aircraft industry in designing engine fragment barriers.