AFRL-AFOSR-VA-TR-2016-0328 Damage Precursor Detection in Polymer Matrix Composites Using Novel Smart Composite Particles

A novel self-sensing framework, utilizing embedded cyclobutane-based mechanophores, was developed for identifying damage precursors and propagation. The novel "smart" material was incorporated into a thermoset polymer matrix and the color change phenomenon was observed under compressive loading. The smart material based polymer system was used to construct glass fiver reinforced composites to investigate the performance of the composite under cyclic loading; the correlation between fluorescence intensity and fatigue cycle was investigated. Fourier Transform Infrared Spectroscopy showed the potential of detecting damage in carbon-containing composites by identifying changes in the peak intensity associated with the mechanically responsive cyclobutane ring. An atomistic simulation methodology was developed in conjunction with the experimental work; the Molecular Dynamics (MD) based methodology was capable of emulating the experiments. After simulating the epoxy curing and ultraviolet (UV) dimerization process, mechanophore activation in the thermoset polymer matrix was successfully emulated. A local work analysis method was developed to evaluate the mechanophore sensitivity quantitatively. The simulation method captured the physical entanglement between epoxy and mechanophore network, which affected the mechanical properties of the polymer matrix significantly. DISTRIBUTION A: Distribution approved for public release. Results from the simulations showed increment in the number of activated cyclobutanes during the deformation test. Good agreement was observed with experimental results: the intensity of fluorescence was found to be directly proportional to the deformation. Distribution Statement This is block 12 on the SF298 form. Distribution A Approved for Public Release Explanation for Distribution Statement If this is not approved for public release, please provide a short explanation. E.g., contains proprietary information. SF298 Form Please attach your SF298 form. A blank SF298 can be found here. Please do not password protect or secure the PDF The maximum file size for an SF298 is 50MB. sf298_AditiChattopadhyay.pdf Upload the Report Document. File must be a PDF. Please do not password protect or secure the PDF . The maximum file size for the Report Document is 50MB. AFOSR Final Report 2016_Aditi_Chattopadhyay.pdf Upload a Report Document, if any. The maximum file size for the Report Document is 50MB. Archival Publications (published) during reporting period: Archival Journal Papers 1. Koo, B., Liu, Y., Zou, J., Chattopadhyay, A., & Dai, L. L., Study of glass transition temperature (Tg) of novel stress-sensitive composites using molecular dynamic simulation. Modelling and Simulation in Materials Science and Engineering, 22(6), (2014): 065018. 2. Zou, J., Liu, Y., Shan, B., Chattopadhyay, A., & Dai, L. L., Early damage detection in epoxy matrix using cyclobutane-based polymers. Smart Materials and Structures, 23(9), (2014): 095038. 3. Zhang, J., Koo, B., Subramanian, N., Liu Y., and Chattopadhyay, A., "An Optimized Cross-Linked Network Model to Simulate Smart Polymeric Material Response", Journal of Intelligent Material Systems and Structures, 24(8), (2015): 085022. 4. Zhang, J., Koo, B., Liu, Y.; Zou, J., Dai, L., and Chattopadhyay, A., "A Novel Statistical Spring-Bead Based Network Model for Self-Sensing Smart Polymer Materials", Smart Materials and Structures, (2015), DOI: 10.1177/1045389X15595292. 5. Zou, J., Liu, Y., Chattopadhyay, A., and Dai, L., "A self-sensing fiber reinforced polymer composite using mechanophore-based smart polymer", Journal of Multifunctional Composites, (2015). 6. Koo, B., Chattopadhyay, A., and Dai, L., Atomistic modeling framework for a cyclobutane-based mechanophore-embedded nanocomposite for damage precursor detection. Computational Materials Science, 120, 135-141 (2016). Conference Papers 1. Zhang, J., Koo, B., Subramanian, N., Liu, Y., & Chattopadhyay, A. "Statistical Multiscale Modeling of Smart Polymer Materials using a Spring-Bead Based Network Model." Proc. of the AIAA SciTech Conference (2014) 2. Koo, B., Liu, Y., Chattopadhyay, A., and Dai, L. "Multiscale Modeling of a Mechanophore-embedded Nanocomposite for Damage Initiation Detection", Proc. AIAA SciTech 2015. 3. Koo, B., Nofen, E., Chattopadhyay, A., and Dai, L., "Multiscale Modeling and Characterization of StressSensitive Mechanophore-Embedded Nanocomposite", Proc. IWSHM September 2015. 4. Johnston, J., Koo, B., Subramanian, N., and Chattopadhyay, A., "Implementation of a Molecular Interphase Model within a Multiscale Framework for Polymer Matrix Composites", Proc. ICCM July 2015. 5. Nofen, E., Zou, J., Wickham, J., Chattopadhyay, A., and Dai, L., "Damage Precursor Detection in Polymer Matrix Composites", Proc. American Chemical Society National Meeting, March 2015. 6. Zhang, J., Koo, B., Liu, Y., and Chattopadhyay, A., "Statistical Multiscale Modeling of Bond Clusters in Smart Polymer using Coupled Molecular Dynamics and Spring-Damper Model", Proc. AIAA SciTech, 2014. 7. Zou, J., Liu, Y., Chattopadhyay, A., & Dai, L. (2015, April). A self-sensing fiber reinforced polymer DISTRIBUTION A: Distribution approved for public release. composite using mechanophore-based smart polymer. In SPIE Smart Structures and Materials and Nondestructive Evaluation and Health Monitoring (pp. 943204-943204). International Society for Optics and Photonics. New discoveries, inventions, or patent disclosures: Do you have any discoveries, inventions, or patent disclosures to report for this period? No Please describe and include any notable dates Do you plan to pursue a claim for personal or organizational intellectual property? Changes in research objectives (if any): Change in AFOSR Program Officer, if any: Dr. David Stargel (previous) Mr. James Fillerup (current) Extensions granted or milestones slipped, if any: AFOSR LRIR Number LRIR Title Reporting Period Laboratory Task Manager Program Officer Research Objectives Technical Summary Funding Summary by Cost Category (by FY, $K) Starting FY FY+1 FY+2