High strength woven fabrics are ideal candidate materials for use in structural systems where high energy absorption is required. Their high strength per weight ratio and the ability to resist high-speed impacts enable them to be very efficient compared to metals. One of the more widely used applications for woven fabrics is in propulsion engine containment systems. As a part of the Federal Aviation Administration’s (FAA) aircraft engine certification regulations, an engine must demonstrate the ability to contain a fan blade released at full operating speed.
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Dry Fabric Composites
High strength woven fabrics are ideal candidate materials for use in structural systems where high energy absorption is required. Their high strength per weight ratio and the ability to resist high speed impacts enable them to be very efficient compared to metals. One of the more widely used applications for woven fabrics is in propulsion engine containment systems. As a part of the Federal Aviation Administration’s (FAA) aircraft engine certification regulations, an engine must demonstrate the ability to contain a fan blade released at full operating speed. Currently the only woven fabric that is in wide use in engine containment systems is Kevlar®49 developed by DuPont in the 1970s. It was the first organic fiber with sufficient tensile strength and modulus to be used in advanced composites. Originally developed as a replacement for steel in radial tires, Kevlar is now used in a wide range of applications. Like nylons, Kevlar filaments are made by extruding the precursor through a spinneret. The rod form of the para-aramid molecules and the extrusion process make Kevlar yarns anisotropic – they are stronger and stiffer in the axial direction than in the transverse direction. The main longitudinal direction of a woven fabric is typically referred to as the warp direction and perpendicular to the warp direction is typically referred to as the fill direction. Hundreds of filaments are bundled together to form a yarn. The engine containment system is typically constructed by wrapping multiple layers of Kevlar®49 around a stiffened metal structure. The fabric is then covered with a protective layer.
The FAA-sponsored research work has resulted in an orthotropic, plasticity model implemented in LS-DYNA commercial computer program as MAT_214.
References
D. Naik, S. Sankaran, B. Mobasher, S. D. Rajan and J. M. Pereira, “Development of Reliable Modeling Methodologies for Fan Blade-Out Containment Analysis. Part I: Experimental Studies”, J of Impact Engineering, 36:1, 1-11, 2009.
Z. Stahlecker, B. Mobasher, S.D. Rajan and J. M. Pereira, “Development of Reliable Modeling Methodologies for Fan Blade-Out Containment Analysis. Part II: Finite Element Analysis”, J of Impact Engineering, 36:3, 447-459, 2009.
S. Bansal, B. Mobasher, S.D. Rajan and I. Vintilescu, “Numerical Modeling of Engine Fan Blade-Out Events”, ASCE J of Aerospace Engineering, 22, 249-259, 2009.
S.D. Rajan and B. Mobasher, “A Comprehensive Methodology for Characterization of Dry Fabrics”, World Journal of Engineering, 7:1, 154-162, 2010.
D. Zhu, B. Mobasher, S.D. Rajan, A. Peled and M. Mignolet, “Modal Analysis of a Servo-hydraulic High Speed Testing Machine and Its Application to Dynamic Tensile Testing at an Intermediate Strain Rate”, Experimental Mechanics, doi: 10.1007/s11340-010-9443-2, 2010. Also Experimental Mechanics, 51:8, 2011.
D. Zhu, B. Mobasher and S.D. Rajan, “Dynamic Testing of Kevlar 49 Fabrics”, ASCE Journal of Materials in Civil Engineering, 23:3, 230-239, 2011.
Zhu, B. Mobasher and S.D. Rajan, “Experimental Study and Modeling of Single Yarn Pull-Out Behavior of Kevlar 49 Fabric”, Composites Part A, 42:7, 868-879, 2011.
D. Zhu, B. Mobasher, S.D. Rajan and P. Peralta, “Characterization of Dynamic Tensile Testing using Aluminum Alloy 6061-T6 at Intermediate Strain Rates”, ASCE J of Engineering Mechanics, (doi:10.1061/(ASCE)EM.1943-7889.0000264), 2011.
D. Zhu, B. Mobasher and S.D. Rajan, “Non-contacting Strain Measurement for Cement-based Composites in Dynamic Tensile Testing”, Cement and Concrete Composites, (doi: 10.1016/j.cemconcomp.2011.09.011), 2011, 34:2, 147-155, 2012.
D. Zhu, B. Mobasher, J. Erni, S. Bansal and S.D. Rajan, “Strain Rate and Gage Length Effects on Tensile Behavior of Kevlar 49 Single Yarn”, Composites Part A, 43:2021-2029, 2012.
D. Zhu, B. Mobasher and S.D. Rajan, “Mechanical Behaviors of Kevlar 49 Fabric Subjected to Uniaxial, Biaxial Tension and In-Plane Large Shear Deformation”, Composites Science and Technology, 74:121-130, 2013.
A. Deivanayagam, A. Vaidya and S.D. Rajan, “Enhancements to Modeling of Dry Fabrics for Impact Analysis”, ASCE J of Aerospace Engineering, 10.1061/(ASCE)AS.1943-5525.0000350 (May 9, 2013).
D. Zhu, A. Vaidya, B. Mobasher and S.D. Rajan, “Finite Element Modeling of Ballistic Impact on Multi-Layer Kevlar 49 Fabrics”, Composites Part B, 56, 254-262, 2013.