About

Gary D. Seidel is a Professor and Assistant Department Head for Academic Affairs in the Kevin T. Crofton Department of Aerospace and Ocean Engineering at Virginia Tech. He earned his Ph.D. in Aerospace Engineering from Texas A&M University in 2007, following his M.S. and B.S. degrees in the same field from the same institution. His research group, Seidel Research Group, focuses on developing analytic and computational multiscale modeling tools based on micromechanics philosophies to capture damage evolution in composites, especially those exhibiting coupled mechanical, thermal, and electromagnetic responses due to active constituent phases or phase transitions. His work addresses challenges related to passing information between nano, micro, meso, and macro scales, as well as across different time scales ranging from femtoseconds to years. Seidel's research emphasizes verification and validation efforts, multiscale characterization, and the generation of statistically meaningful representative volume elements to improve predictive capabilities in composite materials. He has made significant contributions to the understanding of damage initiation and evolution in composites, bridging atomistic and continuum length and time scales, and developing meshless computational tools for dynamic materials and composites.

Research topics

• Materials science
• Composite material
• Nanotechnology
• Structural engineering
• Physics
• Mechanics

Selected publications

• In-Situ Detection of Thermal Hot Spots in Polymer-Bonded Energetic Materials via Multiwalled Carbon Nanotube Networks

  2026-01-08

  articleSenior author
  PublisherDOI

• Self-Sensing Structural Health Monitoring Capabilities of Lunar Regolith Simulant Polymer Concretes Incorporating Epoxy Nanocomposite Binders

  2026-01-08

  articleSenior author

  To enable a permanent human presence on the Lunar surface, advances in technology leading to safer and more resilient structural materials are necessary. Materials containing high mass loadings of native Lunar materials, such as surface regolith, are also desirable because they have the potential to greatly decrease transportation requirements and cost per kg of deployed infrastructure. Structural health monitoring enables the observation of structures and components, either directly or via sensors, to detect or predict strain or damage, allowing for streamlined maintenance, reinforcement, or replacement of compromised elements. Recent advances have allowed such monitoring to be executed in situ via incorporation of carbon nanotubes into composite material binders. However, to date no research has applied these techniques to materials with high loadings of Lunar regolith simulant. This study uses a two-part epoxy binder doped with 0-3% MWCNTs by weight in an 18/82 mass ratio with LHS1 Lunar simulant to investigate the structural health monitoring capabilities of such materials. ASTM D695 compression specimens were tested in an Instron uniaxial testing rig at a displacement rate or 1.3 mm/min. A 10 kHz, 2 V amplitude AC current was passed through attached electrodes and resistance and reactance response was measured via a custom LabVIEW program. Analyses showed that not only can specific compositions enable the detection of strain, damage propagation, and individual damaging events via electrical measurements, but that early warning of changes in structural properties may also be achieved.

  PublisherDOI

• Experimental Determination of Thermal Expansion Behavior in PBEs Using Digital Image Correlation Techniques

  2026-01-08

  articleSenior author

  This study investigates the thermal expansion coefficient of polymer-bonded energetics (PBEs) using Digital Image Correlation (DIC), a non-contact optical technique capable of capturing full-field surface deformations. Cuboid specimens measuring 60 mm × 30 mm × 20 mm and composed of ammonium perchlorate (AP), polydimethylsiloxane (PDMS), and multi-walled carbon nanotubes (MWCNTs) were prepared with a high-contrast speckle pattern created by applying a white base coat followed by stamped black dots for optimal image correlation. The samples were heated to 80°C, held isothermally, and subsequently cooled to 0°C using liquid nitrogen. Axial strain extracted from the DIC measurements was used to calculate the effective thermal expansion coefficient for each formulation, and the results were compared with Voigt–Reuss theoretical bounds that incorporated the measured void volume fraction for each specimen. The thermal expansion coefficients obtained were (1.27 ± 0.05) × 10⁻⁴ °C⁻¹ for AP–PDMS, (1.05 ± 0.12) × 10⁻⁴ °C⁻¹ for AP–CNT 1%–PDMS, and (1.09 ± 0.10) × 10⁻⁴ °C⁻¹ for AP–CNT 2%–PDMS. These findings demonstrate that DIC provides a reliable method for quantifying thermomechanical behavior in PBEs and supports its use in the broader characterization of multifunctional energetic composites.

  PublisherDOI

• Structural health monitoring in epoxy-CNT composites exposed to UV radiation under compressive loadings

  Smart Materials and Structures · 2025-11-18

  articleOpen accessSenior authorCorresponding

  Abstract A large body of current research focuses on the inclusion of carbon nanotubes (CNTs) in a polymer matrix to enable real-time in-situ structural health monitoring via changes in electrical properties. Studies have shown that embedded CNT networks are effective at detecting strain and damage under a variety of load cases. Exposure of epoxy-CNT composites to UV radiation has been observed to instigate both photodegradation of the epoxy matrix and the densification of CNT networks on the material surface. This research explores the effects of UV exposure on the sensitivity of structural health monitoring in 1.0% by weight CNT/epoxy sample sets subjected to monotonic compressive loadings. Specimens were created using EPON 862 epoxy resin and EPIKURE Curing Agent W in a 100/26.4 ratio with the addition of 1.0% multi-walled CNTs by weight. ASTM D695 specimens were created, and a subset was exposed to a target dosage of 61.9 ± 6.2 MJ m −2 of ultraviolet radiation in the 290–400 nm range using a custom exposure chamber. Both the unexposed and exposed subsets were tested in an Instron uniaxial testing frame at a crosshead displacement rate of 1.3 mm min −1 while an inductance-capacitance-resistance meter passed 2 V AC at 10 kHz through attached electrodes. Resistance and reactance changes (normalized to baseline values) were measured and correlated with strain and damage identified by stress–strain relationships. Instantaneous slope measurements in both of the aforementioned regimes were calculated and found to correlate closely with damage events and damage propagation. While some differences in mechanical properties and strain or damage sensitivity between sample sets were detected, all sets showed significant structural health monitoring capabilities. This bodes well for application of this composite in an SHM role in high-UV environments.

  PublisherDOI

• Analytical interaction potential for Lennard-Jones rods

  Physical review. E · 2025-01-03 · 3 citations

  article

  An analytical form has been derived using Ostrogradsky's integration method for the interaction between two thin rods of finite lengths in arbitrary relative configurations in a three-dimensional space, each treated as a line of point particles interacting through the Lennard-Jones 12-6 potential. Simplified analytical forms for coplanar, parallel, and collinear rods are also derived. Exact expressions for the force and torque between the rods are obtained. Similar results for a point particle interacting with a thin rod are provided. These interaction potentials can be widely used for analytical descriptions and computational modeling of systems involving rodlike objects such as liquid crystals, colloids, polymers, elongated viruses and bacteria, and filamentous materials including carbon nanotubes, nanowires, biological filaments, and their bundles.

  PublisherDOI

• Experimental Investigation of Sensing in Polymer Bonded Energetic Materials With MWCNTs Exposed to Elevated Temperature.

  2025-01-03 · 2 citations

  articleSenior author

  This experimental investigation aims to gain insight into the strain- and damage-sensing capabilities of binders containing ammonium perchlorate (AP) and multi-walled carbon nan- otubes (MWCNTs) under thermal loading. Self-sensing behavior is achieved by incorporating MWCNTs into the binder system, where networks of MWCNTs exhibit piezoresistive behavior when subjected to compressive loading. Polydimethylsiloxane (PDMS), an elastomer, is a com- monly used binder in polymer-bonded energetic materials. The addition of MWCNTs enhances the sensing abilities of the material by forming conductive networks. Exploratory results demon- strate that AP-CNT 1% PDMS and AP-CNT 2% PDMS (ammonium perchlorate–multi-walled carbon nanotube–polydimethylsiloxane systems) exhibit effective sensing capabilities due to these conductive networks, while samples without CNTs (AP-PDMS) does not have any sensing capacity. When the samples are placed in an environmental chamber and heated to 80◦C , their electrical resistance increases. However, a significant drop in electrical resistance is observed when the samples are held at this temperature. Upon cooling the samples to room temperature by introducing liquid nitrogen into the chamber, the electrical resistance increases again. These findings indicate that polymer-bonded energetic materials with MWCNTs are capable of sensing thermal changes, as demonstrated by their response to elevated temperatures and subsequent cooling to room temperature.

  PublisherDOI

• Structural Health Monitoring in Epoxy/CNT Composites Exposed to High Doses of UV Radiation

  2025-01-03 · 4 citations

  articleSenior author

  Previous research into carbon nanotube(CNT)/polymer composites has provided evidence that these materials enable strain and damage sensing via electrical monitoring as embedded conductive CNT networks change with internal material state. However, no current research exists to verify that these properties persist in extreme environments, such as those on the Lunar surface, where temperature and radiation exposure are much more significant than in terrestrial applications. This research will focus on verification of structural health monitoring functionality of a 0.99% CNT/epoxy composite exposed to a concentrated dose ( ∼70 MJ/m^2) of UV radiation in the 290-400 nm wavelength range. The material system used herein is an EPON 862/EPICURE W epoxy mixture prepared according to manufacturer recommendations, with the addition of 1% multi-walled carbon nanotubes relative to binder weight. This composite was molded into ASTM D695 compression specimens, smoothed and electroded, and subjected to mechanical testing on an Instron uniaxial testing rig with a 1.3 mm/min crosshead displacement rate. Concurrently, 10 kHz 2V AC was applied to the electrodes using an inductance capacitance resistance (LCR) meter, and resistance and reactance responses were measured. These results were analyzed using an in-house MATLAB code. Results displayed in this paper are for two specimens each from unexposed and exposed sample sets. In spite of significant changes in material behavior, strain and damage sensing capabilities persist after UV exposure, making this composite a viable option for extreme irradiance applications.

  PublisherDOI

• Micrometeoroid Impact Detection on Lunar Structures: A Peridynamics Approach

  2025-01-03

  articleSenior author

  The absence of atmosphere in the extreme lunar environment poses imminent danger to future lunar structures subject to micrometeoroid impacts. This work proposes active structural health monitoring and damage detection of lunar structures that can be achieved by monitoring the piezoresistive response of multifunctional composites, comprised of lunar regolith, polymer binder and carbon nanotubes. Computational simulations are performed to demonstrate the electrical response to meteoroid impact, using an in-house coupled electromechanical peridynamics code, TemPer3D. The effects of micrometeoroid velocity, impact angle, and size are analyzed to demonstrate the effectiveness of peridynamic modeling in capturing the piezoresistive response to micrometeoroid impacts.

  PublisherDOI

• Analytical Interaction Potential for Lennard-Jones Rods

  arXiv (Cornell University) · 2024-05-07

  preprintOpen access

  An analytical form has been derived using Ostrogradski's integration method for the interaction between two thin rods of finite lengths in arbitrary relative configurations in a 3-dimensional space, each treated as a line of material points interacting through the Lennard-Jones 12-6 potential. Simplified analytical forms for coplanar, parallel, and collinear rods are also derived. Exact expressions for the force and torque between the rods are obtained. Similar results for a point particle interacting with a thin rod are provided. These interaction potentials can be widely used for analytical descriptions and computational modeling of systems involving rod-like objects such as liquid crystals, colloids, polymers, elongated viruses and bacteria, and filamentous materials including carbon nanotubes, nanowires, biological filaments, and their bundles.

  PublisherOA PDFDOI

• Reduced-Order Representation and Effective Property Prediction of CNT-polymer nanocomposites using Convolutional Neural Networks and Autoencoders

  2024-01-04

  articleSenior author

  In this work, Convolutional Neural Networks (CNNs) are trained to predict the effective stiffness, electrical conductivity, and piezoresistivity of computationally generated CNT-polymer composite statistical volume elements (SVEs). It is found that the distributions of the properties predicted by the CNN accurately match those predicted by FEM. However, the CNN fails to predict the properties of individual SVEs with sufficient accuracy. Further, multi-objective supervised autoencoders (SAEs) are trained to obtain a reduced-order representation that allows the prediction of the effective stiffness of the SVEs while simultaneously reconstructing the SVEs accurately. The SAE predicts the distribution of the stiffness at all CNT volume fractions with adequate accuracy, but fails to predict the stiffness of individual SVEs with sufficient accuracy.

  PublisherDOI

Recent grants

• Planning Visits Concerning Electric and Electro-mechanical Properties of CNT-polymer Nanocomposites: An Experimental and Multiscale Modeling Approach

  NSF · $20k · 2010–2012

Frequent coauthors

• Dimitris C. Lagoudas

  Texas A&M University

  31 shared

• Adarsh K. Chaurasia

  Ansys (United States)

  18 shared

• Krishna Kiran Talamadupula

  15 shared

• Stefan J. Povolny

  13 shared

• Engin C. Sengezer

  13 shared

• Xiang Ren

  University of Electronic Science and Technology of China

  13 shared

• Naveen Prakash

  Corning (United States)

  11 shared

• Nishant Shirodkar

  8 shared

Labs

• Seidel Research GroupPI

Education

• Doctor of Philosophy, Aerospace Engineering

  Texas A&M University

  2007

• Master of Science, Aerospace Engineering

  Texas A&M University

  2002

• Bachelor of Science, Aerospace Engineering

  Texas A&M University

  1999

Awards & honors

• ASME Fellow, 2020
• AIAA Associate Fellow, 2013
• Oak Ridge Associated Universities Ralph E. Powe Junior Facul…
• 2016 ASME/Boeing Best Paper Award for 2016 AIAA SciTech pape…
• Virginia Tech Dean's Award for Excellence in Service