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Search Publications by: Donald L. Hunston (Assoc)

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Displaying 1 - 25 of 126

Long-Term Environmental Fatigue of Pultruded Glass-Fiber-Reinforced Composites

October 12, 2021
Author(s)
Kate Liao, Carl R. Schultesiz, Donald L. Hunston
Pultruded glass-fiber-reinforced vinyl ester composite coupons were subjected to four-point-bend fatigue in various environments to study long-term durability for infrastructure applications. Several groups of specimens were aged in water or in water

The Effects of Water on the Fatigue Behavior for Pultruded Glass-Reinforced Composite

October 12, 2021
Author(s)
Kate Liao, Carl R. Schultesiz, Donald L. Hunston, L C. Brinson
Pultruded composites are finding increasing use in infrastructure and marine applications where they see prolonged exposure to environmental factors such as moisture. This work examines the fatigue behavior (4 point bending) in air and water for pultruded

EFFECTS OF PRE-STRAIN ON THE NON-LINEAR VISCOELASTIC PROPERTIES OF A MODEL SEALANT

November 18, 2020
Author(s)
Christopher C. White, Donald L. Hunston, Kar tean Tan
The non-linear viscoelastic properties of a model sealant were measured using stress relaxation tests conducted at different strain levels, x. Some specimens were measured with no previous strain history while others were given a preconditioning that

Macroscopic degradation behaviors of polyethylene under the influence of UV radiation and temperature

February 17, 2020
Author(s)
Hsiang C. Hsueh, Jae H. Kim, Sara Orski, Andrew Fairbrother, Deborah Jacobs, Donald L. Hunston, Christopher C. White, Li Piin Sung, Lakesha Perry
Accelerated weathering tests were performed to investigate the effects of multiple ultraviolet (UV) light intensities and temperatures on the tensile behavior of high-density polyethylene (HDPE). In the macroscopic degradation behavior of HDPE, tensile

Validating Predictive Models with Outdoor Data

October 17, 2019
Author(s)
Christopher C. White, Donald L. Hunston, Li Piin Sung, Hsiang C. Hsueh, Adam L. Pintar, Deborah S. Jacobs
The NIST service life prediction program has demonstrated success in producing validated predictions for the property change resulting from outdoor exposure for a range of polymer systems including Epoxy, Polyethylene, Polyester, Polyethylene terephthalate

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

Service Life Prediction Models to Predict Building Skin Failures

October 1, 2018
Author(s)
Christopher C. White, Donald L. Hunston, Adam L. Pintar
Determination of the in-service performance and failure of a building envelope material exposed to outdoor weathering has been a significant research goal for the last 100 years. Typically, estimations of the time to failure or durability of a material is

A Kinetics Based Models for Environmentally Induced Sealant Degradation

February 12, 2018
Author(s)
Donald L. Hunston, Christopher C. White
Caulks and sealants are a critical part of any structure that is exposed to the environment. Although they are good materials, they eventually fail, and the failure is often difficult to detect before extensive damage is generated by water ingress or loss

Accelerated Testing: Challenges and Opportunities.

December 19, 2017
Author(s)
Christopher C. White, Donald L. Hunston
Materials exposed to outdoor weathering will change properties. Currently there are no test methods that result in predictions for those materials. This lack of an ability to predict how the properties will change with weathering results in three problems

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

Durability of Carbon Nanotube Polymer-Fiber Composites

July 25, 2016
Author(s)
Aaron M. Forster, James Alexander Liddle, Donald L. Hunston, Ajay Krishnamurthy
Significant composite strength improvements have been achieved using highly aligned and dense carbon nanotube fibers with low resin concentration, but these remain ac-cessible only to aerospace applications [1]. The potential of carbon nanotubes for high

ROLE OF SALT ON ADHESION OF AN EPOXY/ALUMINUM (OXIDE) INTERFACE IN AQUEOUS ENVIRONMENTS

November 5, 2015
Author(s)
Kar T. Tan, Christopher C. White, Donald L. Hunston, Justin M. Gorham, Michael Imburgia, Aaron M. Forster, Vogt D. Bryan
Engineering joints consisting of polymer/inorganic interfaces are commonly exposed to less than ideal conditions during normal service; these environmental conditions present a significant challenge for maintaining the structural integrity of the interface

Applied Strain on Sealant Samples Exposed to Outdoor Weather

October 19, 2015
Author(s)
Christopher C. White, Donald L. Hunston, Kar tean Tan
In outdoor exposures used to establish durability of sealant formulations, applied strain is typically absent. It is a critical aspect of the in-service environment. This research employs two recently available techniques to examine how the presence of

Aging of Polymeric Films used in Protective Glazing Systems

July 7, 2015
Author(s)
Christopher C. White, Donald L. Hunston, Kar T. Tan
The toughness of polymer and glass laminates or win-dow glazing, are used to protect buildings and occupants from shattered glass resulting from natural disasters (e.g., hurricanes, tornadoes, seismic events), and intentional events (e.g., robbery

ELEVATED TEMPERATURE ADHESION TESTING OF SPRAY-APPLIED FIRE-RESISTIVE MATERIALS

May 13, 2015
Author(s)
Christopher C. White, Kar T. Tan, Donald L. Hunston, Walter E. Byrd
Effective fire protection of steel can be fully realized when spray-applied fire resistive materials (SFRMs) are bonded sufficiently to structural steel during the event of fire. The adhesion mechanisms and characterization at elevated temperatures

MECHANISMS OF CRITICALITY IN ENVIRONMENTAL ADHESION LOSS

May 13, 2015
Author(s)
Christopher C. White, Kar T. Tan, Donald L. Hunston, Kristen L. Steffens, Deborah S. Jacobs, Bulent Akgun, Vogt D. Bryan
Moisture attack on adhesive joints is a long-standing scientific and engineering problem. A particularly interesting observation is that when the moisture level in certain systems exceeds a critical concentration, the bonded joint shows a dramatic loss of

Prediction of Sealant Modulus Change due to Outdoor Weathering

May 13, 2015
Author(s)
Christopher C. White, Kar T. Tan, Donald L. Hunston, Adam L. Pintar, James J. Filliben
An empirically-based model has been created to predict the change in modulus for a sealant exposed to outdoor weathering. The underlying high precision data supporting this model was obtained using the NIST SPHERE (Simulated Photo degradation by High

IMPACT OF ENVIRONMENTAL FACTORS ON POLYMERIC FILMS USED IN PROTECTIVE GLAZING SYSTEMS

March 11, 2015
Author(s)
Christopher C. White, Kar T. Tan, Donald L. Hunston, Aaron M. Forster, Deborah S. Jacobs
Accelerated and natural aging of safety films used in protective glazing systems was investigated by the use of Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy and tensile tests. Accelerated conditions involved simultaneous

Viscoelastic Characterization of Fusion Processing in Bimodal Polyethylene Blends

June 2, 2014
Author(s)
Aaron M. Forster, Wei-Lun Ho, Kar T. Tan, Donald L. Hunston
Polyethylene is an advantageous material for the construction of buried pipelines. It is corrosion resistant, seismic tolerant, and utilizes low cost installation methods. Pipe sections are often joined using thermal fusion processes. The strength of the

Micro-Deformation in the Fracture of a Toughened Epoxy

February 24, 2014
Author(s)
Donald Hunston, Cyril Clerici, Aurelien Blond, Aaron M. Forster
Thermoset resins are used in many composites and structural adhesives because they have excellent proper-ties. Unfortunately, they tend to be quite brittle. Over the last 50 years, there has been a major effort to improve the toughness of thermosets, and