The Response of Textile Composites Subjected to Elevated Loading Rates.

The United States military is involved in a number of peacekeeping and combat operations throughout the world. In an effort to increase the deployability and agility of the military, a number of novel technologies are being developed. Lightweight combat vehicles have relied on thick structural members, typically made of metallic materials, to defend against specific threats including Improvise Explosive Devices (IEDs) and live fire munitions. While these techniques have proven successful in the past, the weight considerations greatly affect the mobility of these vehicles. Modern armoring techniques have been developed that include the use of Fiber Reinforced Polymer Composites (FRPCs) that offer high structural rigidity while reducing the weight of the vehicle. Because traditional composite laminates suffer from delamination which does not allow the material to reach its full mechanical performance, a new class of 3D composite materials, referred to as 3D textile composites, have been developed. 3D Textile composites involve the interweaving of fiber yarns in a number of preforms to achieve a desired mechanical performance. In this thesis, the high strain rate tensile response of 3D textile composites is addressed. Traditional 1-dimensional high strain rate tensile testing of composite materials is used to understand the failure mechanics of a single fiber tow and to develop constitutive models that are subsequently used to explain the results of textile composites under single and multi-axial load states at quasi-static and high rates of loading. Plain woven textile composites are subjected to shock loading in a shock tube facility to produce biaxial tensile load states. The deformation response is measured using digital image correlation. Experimental results are used as motivation to construct finite element models, including different length scales to understand and explain the observed deformation response and failure mechanics of textile laminates.PhDMechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/113554/1/bjustuss_1.pd