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Search Publications by: Amanda L. Forster (Fed)

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Displaying 1 - 25 of 64

Effect of Aging on Unidirectional Composite Laminate Polyethylene for Body Armor

March 8, 2023
Author(s)
Amy Engelbrecht-Wiggans, Ajay Krishnamurthy, Amanda L. Forster
Ballistic-resistant body armor has increasingly been using flexible unidirectional (UD) composite laminates that comprise multiple layers in the armor construction. Each UD layer contains high-performance fibers held in place using very low modulus binder

Analysis of Strain Correction Procedures for Single Fiber Tensile Testing

December 29, 2022
Author(s)
Amy Engelbrecht-Wiggans, Amanda L. Forster
Accurate strain measurement for single fibers is critical for many engineering applications. Typically, the crosshead displacement is used to calculate strain when performing mechanical testing, however there are complicating factors: slack in the specimen

Relative effects of polymer composition and sample preparation on glass dynamics

August 17, 2022
Author(s)
Christopher Soles, Amanda L. Forster, Katherine Evans, Madhusudan (Madhu) Tyagi, Robert M. Elder, Timothy Sirk, Joseph Dennis, Kanae Ito, Osama Yamamuro, Hiroshi Akiba
Modern design of common adhesives, composites and polymeric parts makes use of polymer glasses that are stiff enough to maintain their shape under a high stress while still maintaining a ductile behavior after the yield point. Typically, material

Effects of Thermal Aging on Molar Mass of Ultra-High Molar Mass Polyethylene Fibers

March 24, 2022
Author(s)
Zois Tsinas, Sara Orski, Viviana Bentley, Lorelis Gonzalez-Lopez, Mohamad Al-Sheikhly, Amanda L. Forster
Ultra-high molar mass polyethylene (UHMMPE) is commonly used for ballistic-resistant body armor applications due to the superior strength of the fibers fabricated from this material combined with its low density. However, polymeric materials are

Temperature-insensitive silicone composites as ballistic witness materials: the impact of water content on the thermophysical properties

July 28, 2021
Author(s)
Ran Tao, Fan Zhang, Huong Giang Nguyen, Philip Bernstein, Amanda L. Forster, Randy Mrozek, Aaron M. Forster
In this work, different formulations of a room-temperature silicone composite backing material (SCBM) composed of polydimethylsiloxane (PDMS), fumed silica and corn starch were investigated using different characterization techniques, i.e., differential

Comparison of theoretical and experimental failure distributions for twisted yarns

September 14, 2020
Author(s)
Amy E. Engelbrecht-Wiggans, Amanda L. Forster
Both untwisted and twisted bundles of fibers and wires can be found in a myriad of applications, from ballistic body armor to suspension bridge cables. Predicting the bulk bundle failure distribution based on single fiber or wire tests is of interest as

Linking Theory to Practice: Predicting Ballistic Performance from Mechanical Properties of Aged Body Armor

August 24, 2020
Author(s)
Amanda L. Forster, Dennis D. Leber, Amy E. Engelbrecht-Wiggans, Virginie A. Landais, Allen Chang, Emilien J. Guigues, Guillaume Messin, Michael A. Riley
It has long been a goal of the body armor testing community to establish an individualized, scientific-based protocol for predicting end-of-life of fielded body armor ballistic performance. A major obstacle in achieving this goal is that the test methods

Effects of temperature and humidity on high-strength p-aramid fibers used in body armor

April 14, 2020
Author(s)
Amy E. Engelbrecht-Wiggans, Faraz A. Burni, Emilien Guigues, Shefei Jiang, Vivian Yu, Thang Huynh, Zois Tsinas, Deborah Jacobs, Amanda L. Forster
To improve the reliability and design of body armor, it is imperative to understand the failure modes and the degradation rates of the materials used in armor. Despite the best efforts of manufacturers, some vulnerability of armor materials to aging due to

Effect of Elevated Temperature and Humidity on Fibers Based on 5-amino-2-(p-aminophenyl) benzimidazole (PBIA)

March 19, 2020
Author(s)
Amy E. Engelbrecht-Wiggans, Ajay Krishnamurthy, Lucas H. Kaplan, Amanda L. Forster, Thanh N. Hoang, Viviana Bentley
Traditionally, soft body armor has been made from materials such as poly(p-phenylene terephthalamide) (PPTA) and ultra-high molar mass polyethylene (UHMMPE). However, to diversify the fiber choices in the United States body armor market, copolymer fibers

Tensile Testing of Aged Flexible Unidirectional Composite Laminates for Body Armor

September 27, 2019
Author(s)
Amy E. Engelbrecht-Wiggans, Faraz A. Burni, Amanda L. Forster
Flexible Unidirectional (UD) composite laminates are commonly being used for ballistic- resistant body armor. These laminates are comprised of UD layers, each constructed by laminating thin layers of high-performance fibers held in place using binder

Multiscale polymer dynamics in hierarchical carbon nanotube reinforced glass fiber composites

June 5, 2019
Author(s)
Ajay Krishnamurthy, Ran Tao, Erkan Senses, Sagar Doshi, Erik Thostenson, Faraz Burni, Bharath Natarajan, Donald L. Hunston, Amanda L. Forster, Aaron M. Forster
Carbon-nanotube (CNT) grafted glass fiber reinforced epoxy nanocomposites (GFRP) present a hierarchy of stiffness (GPa to MPa) and lengths (µm to nm) scales at the fiber-matrix interphase. The contribution of interfacial CNT networks to the local and bulk

Protocols for tensile testing flexible unidirectional composite laminates

April 27, 2019
Author(s)
Amy E. Engelbrecht-Wiggans, Ajay Krishnamurthy, Faraz A. Burni, William A. Osborn, Amanda L. Forster
Many body armor designs incorporate unidirectional (UD) laminates. UD laminates are constructed of thin layers of high performance yarns where the yarns in each layer are oriented parallel to each other and held in place using binder resins and thin

Evaluation of Degradation Models for High Strength p-Aramid Fibres Used in Body Armour

October 1, 2018
Author(s)
Kirk D. Rice, Amy E. Engelbrecht-Wiggans, Emilien J. Guigues, Amanda L. Forster
To improve the reliability and design of armour, it is imperative to understand the failure modes and the degradation rates of the materials used in armour. Despite the best efforts of manufacturers, some vulnerability of armour materials to ageing due

Protocols for Determining the Mechanical Properties of High Strength Copolymer Aramid Fibers

September 1, 2018
Author(s)
Amanda L. Forster, Viviana Rodriguez Cardenas, Ajay Krishnamurthy, Amy E. Engelbrecht-Wiggans, Zois Tsinas
The primary goal of the manuscript is to develop a protocol to prepare consistent specimens for accurate mechanical testing of high strength copolymer aramid fibers, by removing a coating and disentangling the individual fiber strands without introducing

Hierarchical Cellulose Nanocrystal Blends for Bioinspired Damage Tolerant Photonic Films

May 4, 2018
Author(s)
Bharath NMN Natarajan, Ajay Krishnamurthy, Caglar Dogu Emiroglu, Amanda L. Forster, E. J. Foster, Christoph Weder, Douglas M. Fox, Jan Obrzut, Jeffrey W. Gilman
Attempts to emulate strong and tough natural composites using wood cellulose nanocrystals (CNCs) fall short in mechanical performance due to the low shear transfer ability of CNC interfaces in their helicoidal ensembles. This shortcoming is ascribed to the

Enhanced durability of CNT based hierarchical composites subjected to accelerated aging environments.

September 21, 2017
Author(s)
Ajay Krishnamurthy, Donald L. Hunston, Amanda L. Forster, Bharath NMN Natarajan, Sunny Wicks, Paul E. Stutzman, James A. Liddle, Aaron M. Forster, Brian L. Wardle
As carbon nanotube (CNT) based composites are increasingly being identified as viable aerospace materials, it is vital to study their environmental degradation characteristics. In this work, the durability of CNT reinforced hierarchical alumina fiber