About

Landon Grace is an Associate Professor in the Department of Mechanical and Aerospace Engineering at NC State University. He joined the faculty in 2016 after spending four years as an Assistant Professor at the University of Miami. Dr. Grace completed his PhD at the University of Oklahoma, during which he worked full-time at Tinker Air Force Base for five years as an aerospace engineer and was a graduate of the USAF Palace Acquire Program. His research focuses on the response of composite materials to detrimental environments, emphasizing temperature extremes, polymer-penetrant interactions, and combined hygrothermal and mechanical loading. His work is highly multidisciplinary, involving collaborations with researchers in the medical field, as well as in mechanical, aerospace, biomedical, and materials engineering.

Research topics

• Materials science
• Composite material
• Computer Science
• Chemistry
• Engineering
• Organic chemistry
• Nanotechnology
• Electrical engineering
• Thermodynamics
• Physics
• Chemical physics
• Mechanical engineering
• Embedded system
• Chemical engineering
• Optoelectronics

Selected publications

• Bio-Based Epoxy Natural Fiber Composites for Marine Energy Harvesting

  2026-01-01

  book-chapterSenior author
  PublisherDOI

• Parametric Evaluation of Low Velocity Impact Damage in Polymer Composites Using Aquaphotomics-Based Near Infrared Spectroscopy

  SSRN Electronic Journal · 2025-01-01

  preprintOpen accessSenior author
  PublisherDOI

• Parametric evaluation of low velocity impact damage in polymer composites using aquaphotomics-based near infrared spectroscopy

  Composites Part A Applied Science and Manufacturing · 2025-12-16 · 1 citations

  articleOpen accessSenior authorCorresponding

  • Near infrared spectroscopy detects early-stage impact damage in polymer composites. • Absorbance area parameter enables quantification of low velocity impact damage. • NIRS outperforms ultrasonic testing for subtle damage detection in glass/epoxy laminates. • Moisture-polymer interactions reveal internal changes linked to damage progression. • Results support noninvasive monitoring methods for safety–critical composite structures. Polymer composites are increasingly used in safety–critical structures, such as aircraft wings and fuselages, wind turbine blades, and boat hulls, across the aerospace, energy, and marine industries, owing to their advantageous properties. However, they are prone to Low-Velocity Impact (LVI) events, which can initiate subsurface damage, compromising their long-term integrity and performance. This necessitates effective techniques for the damage evaluation of polymer composites. This study explored the application of Near-Infrared spectroscopy (NIRS) to detect and quantify LVI damage in E-glass/epoxy laminates. NIRS leverages moisture-polymer interactions to identify internal structural changes. Samples exhibiting barely visible impact damage (BVID) were systematically inspected using a Nano NIRS Evaluation Module across various moisture levels, and the data were analyzed using multivariate analysis of spectral data. Two damage parameters were developed and evaluated: (1) the Absorbance Area (AA), and (2) the Free-to-Bound water ratio (FBWR). The results demonstrate the potential of NIRS for identifying and quantifying damage, showing a strong correlation between moisture content and damage extent. Phased Array Ultrasonic Testing (PAUT) was employed for comparative analysis. This study shows the effectiveness of NIRS application in the evaluation of LVI damage in polymer composites and highlights a new pathway for early damage detection in composites.

  PublisherDOI

• Evaluating machine learning classifiers for glaucoma referral decision support in primary care settings

  UNC Libraries · 2025-05-01

  articleOpen access1st authorCorresponding
  PublisherDOI

• Verification and validation of dielectric mapping technique for non‐destructive evaluation of polymer matrix composites

  Polymer Composites · 2024-08-13 · 3 citations

  articleOpen accessSenior authorCorresponding

  Abstract The rapid increase in use of polymer matrix composites in different industries underscores the need for reliable non‐destructive evaluation techniques to characterize small‐scale damage and prevent structural failure. A novel dielectric technique exploits moisture‐polymer interactions to identify and track damage, leveraging differences in dielectric properties between free and bound water. This technique has demonstrated the ability to detect low levels of damage, but the localization accuracy has not yet been evaluated. This work utilizes unsupervised machine learning to assess the technique's ability to identify the damage boundary following a low‐velocity impact event. Bismaleimide/quartz and E‐glass/epoxy laminates were impacted via drop tower to induce varying levels of damage, and subsequently inspected via dielectric technique at several moisture levels by weight. Resulting data was processed via k‐means clustering and the identified damage boundary was compared to a boundary obtained from backlit images and scanning electron microscopy. Accuracy was quantified using developed metrics for damage centroid and boundary identification. The technique averaged 93.9% accuracy in determining the damage center and 77.5% accuracy in identifying the damage boundary. Results indicated the technique's effectiveness across varying moisture levels, particularly in damage centroid identification. Localization accuracy was shown to be insensitive to moisture content, improving the technique's practical capabilities. Further analysis revealed potential for delineation of delaminations. Highlights Low‐velocity impact of two material architectures. Damage boundary determined and validated via scanning electron microscopy. Detected damage site via dielectric technique compared to damage boundary. High technique accuracy revealed; >90% centroid localization accuracy. Potential for delamination delineation observed.

  PublisherDOI

• Quantifying Patient Preferences and Expectations About Diabetic Retinopathy Monitoring

  JAMA Ophthalmology · 2024-12-19

  articleOpen access

  Importance: Diabetic retinopathy (DR) is the leading cause of blindness among adults in the US. The US Centers for Disease Control and Prevention recommends annual DR monitoring for all individuals with diabetes, yet monitoring rates remain below 70%. Objective: To evaluate how patient preferences and expectations about DR monitoring are associated with expected monitoring adherence behaviors. Design, Setting, and Participants: In this survey study, a web-enabled survey instrument was developed and implemented with a discrete-choice experiment to characterize patient preferences for outcomes of DR monitoring and graded-pair questions to quantify patients' expectations about the impact of DR monitoring on blindness risk. The survey was conducted through ResearchMatch, a US National Institutes of Health-developed online platform, among adults with self-reported, physician-diagnosed diabetes. Recruitment occurred between September 15, 2023, and October, 17, 2023, and data analysis occurred between October 2023 and December 2023. Results from the 2 tasks were combined to derive patients' expected monitoring behavior following a recently proposed treatment adherence framework. The survey instrument was pretested in cognitive interviews and validated for the purposes of this study. Exposure: Survey-based discrete-choice experiment and graded-pair questions. Main Outcomes and Measures: Participants' relative preferences for DR-related blindness risk reductions, monitoring time, and out-of-pocket monitoring costs were quantified, as well as the degree to which participants expected adherence to monitoring to affect the risk of blindness. By combining how much participants valued specific reductions in blindness risk (relative to monitoring costs) and their expected risk reduction through monitoring, the rate at which patients would maximize the benefit of monitoring appointments was assessed. Results: The survey was completed satisfactorily by 304 respondents of 542 individuals invited to participate. Mean (SD) respondent age was 40.5 (11.2) years, and 169 respondents (56.1%) were female. Reductions in blindness risk were valuable to participants. Participants required a 3.87 (95% CI, 1.91-5.88) percentage-point reduction in 5-year blindness risk to be fully adherent to an annual 53-minute monitoring visit with a $26 co-payment, but respondents expected DR monitoring to reduce the 5-year blindness risk by 0.71 (95% CI, 0.21-1.28) percentage points. Conclusions and Relevance: In this online survey study among adults with diabetes, measurement of patient preferences and expectations about DR monitoring with properly validated instruments offered an opportunity to assess patient health behaviors. The association between preferences and monitoring expectations was generally consistent with monitoring nonadherence among adults with diabetes and offers insights that may help address inconsistent DR monitoring.

  PublisherOA PDFDOI

• A coupled approach of spatial dielectric mapping and unsupervised machine learning for damage detection and severity segmentation in polymer matrix composites

  NDT & E International · 2024-05-03 · 4 citations

  articleSenior authorCorresponding
  PublisherDOI

• A PERFORMANCE COMPARISON OF LOW-COST NIR NANO TO NIR MICROPHAZIR FOR POLYMER COMPOSITE CHARACTERIZATION

  2023-09-18 · 3 citations

  articleSenior author

  Polymer composites are increasingly adopted to complement or replace their metal counterparts used in aerospace, wind turbine, automotive, and other safety-critical structures. However, these structures are susceptible to the development of undetected sub-surface damage, such as low velocity impact damage (LVI), that limits their performance and utility in certain cases. The ability to detect and monitor the progression of this type of damage from the micron level prior to growth to the macroscale is critical to ensuring the long-term safety and reliability of these structures. Near Infrared Spectroscopy (NIRS) is a promising technique for detecting LVI damage because it can probe the internal structure of the material and identify subtle changes in its properties. This study compared the performance of a low-cost NIR Nano (a Texas Instruments NIR Nano evaluation model) to a commercial NIR Microphazir instrument for the detection of LVI damage in glass fiber reinforced polymer composites. We evaluated the two instruments for their ability to detect and measure different levels of impact damage at increasing moisture absorbed by weight. Forty-eight fiberglass laminates consisting of e-glass and epoxy were subjected to either 0J (no damage), 1J, 1.5J, and 2J impact energy using a drop tower outfitted with a 9mm radius hemispherical striker tip impactor. Spectral scans were collected between wavelengths of 900-1700 nm (NIR Nano) and 1600-2400 nm (Microphazir) for all samples prior to moisture absorption. Following moisture contamination, spectral scans were taken at regular intervals of gravimetric moisture gain from 0.05% to 0.15% by weight. Multivariate data analysis methods were used to assess the spatial variation of the absorbance parameter at various amounts of absorbed moisture. The results and discussion emphasize the importance of rigorous calibration and technique selection for reliable and accurate NIR spectroscopy investigation in polymer composites, especially in situations where mobility,

  PublisherDOI

• Identifying the Factors that Influence the Use of Care Coordination in Diabetic Retinopathy Screening

  Proceedings of the Human Factors and Ergonomics Society Annual Meeting · 2023-09-01

  article

  Coordination of the necessary efforts of medical personnel, caregivers, and social networks to support a patient with a chronic health condition increases time consumption and costs. According to a CDC study from 2023, six out of ten Americans suffer from chronic illnesses, including diabetes, which can lead to other medical complications like diabetic retinopathy (DR). Care coordination programs are one of the systems currently in use to assist in the management of patient’s healthcare and the network of individuals involved in their treatment plans. Compared to institutions that utilize fewer care coordination systems, those that use these programs consistently have much higher patient attendance rates. Therefore, it is important that to improve the current systems we comprehend the user experience with care coordination. To study the barriers and motivations underlying participation in care coordination programs among diabetes patients, we created an interview utilizing the Integrated Behavior Model (IBM). The findings from our interviews will contribute to the body of existing literature by identifying barriers and motivators that must be taken into consideration when designing DR screening system aids.

  PublisherDOI

• Identifying Barriers and Motivators in Diabetic Eye Examination to Design Medical Screening Systems

  Proceedings of the International Symposium on Human Factors and Ergonomics in Health Care · 2023-03-01

  article

  Diabetic Retinopathy (DR) is the main contributor to adult blindness in America. When detected on time, treatment can avoid severe sight loss 95% of the time (Fong et al., 2004). However, only 50% of people with diabetes get screened yearly, making early intervention difficult (Lee, et al., 2003). There is a need to understand how the systems for DR screenings can be designed to comply with the patient's needs, for which it is necessary to understand the user and the factors that affect their behavior. We created a questionnaire from barriers and motivators found in interviews with persons with diabetes regarding their yearly screenings (Salas, et.al., 2022) based on Ajzen’s (2006a) Constructing a Theory of Planned Behavior Questionnaire. The questionnaire measured the influence of attitudes, social norms, and perceived control on screening for DR. This study will add to the current body of literature by helping to identify where to focus efforts when creating systems for DR screening.

  PublisherDOI

Recent grants

• CAREER: Exploiting the Dynamic Dielectric Behavior of Water to Understand and Predict Polymer Composite Damage Progression

  NSF · $607k · 2018–2024

Frequent coauthors

• Rishabh D. Guha

  Lawrence Berkeley National Laboratory

  17 shared

• Katherine Berkowitz

  Sandia National Laboratories

  15 shared

• Mauro Fittipaldi

  University of Miami

  14 shared

• Ogheneovo Idolor

  North Carolina State University

  12 shared

• Omkar G. Kaskar

  North Carolina State University

  9 shared

• L. A. Rodríguez

  Universidad Andina del Cusco

  9 shared

• Carla García

  University of Miami

  8 shared

• David Fleischman

  6 shared

Awards & honors

• NSF CAREER Award (2018)