Fire Protection Engineering Theses and Dissertations
Permanent URI for this collectionhttp://hdl.handle.net/1903/2772
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Item EVALUATION OF IMPACT OF NOVEL BARRIER COATINGS ON FLAMMABILITY OF A STRUCTURAL AEROSPACE COMPOSITE THROUGH EXPERIMENTS AND MODELING(2021) Crofton, Lucas; Stoliarov, Stanislav; Fire Protection Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Composites have become a integral part of the structure of airplanes, and their use within aircraft continues to grow as composites continue to improve. While polymer composites are an improvement in many facets to traditional airspace materials, their flammability is something called into question. The work performed for this study was to create a pyrolysis model for a particular aerospace composite, IM7 graphite fiber with Cytec 5250-4 Bismaleimide matrix (BMI), and three innovative composite barrier coatings that could be applied to the BMI to potentially improve its performance in fire scenarios. The composites were all tested individually, in a series of milligram-scale tests, and the test results were inversely analyzed to determine stoichiometry, chemical kinetics, and thermodynamics of their thermal decomposition and combustion. Gram-scale experiments using the Controlled Atmosphere Pyrolysis Apparatus II (CAPA II) were performed on the BMI by itself and then again with one of each of the composite barrier coatings applied in a defined thickness. This data were inversely analyzed to define the thermal conductivity of the sample and resolve it’s emissivity. It was found after fully defining a pyrolysis model for each composite material that the composite barrier coatings did not provide any benefit to the base composite BMI, and only added more fuel load which in turn contributed to a increase in heat release rate when computational simulations were run to mimic a airplane fuel fire.Item PYROLYSIS MODELING AND MATERIAL PROPERTY VALIDATION WITH FLAME HEAT FEEDBACK MODEL APPLICATION(2021) Bhatia, Deepanshu Kishan; Milke, James A; Fire Protection Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Materials used in the built environment specially in upholstered furniture in business and residential occupancies act as primary fuel load in fires. This is a cause of concern not only for the building developers but for fire investigators, fire researchers and fire modelers. NIJ Technology Working Group’s Operational Requirements for Fire and Arson Investigation have laid out research needs with respect to knowledge of the thermo-physical properties of materials that are common in the built environment. To fill the gaps that limit the analysis capability of fire investigators and engineers, one of the requirement outlined is of adequate material property data inputs for fire modeling as well as fire model validation. The objectives of this study are to measure thermo-physical material properties of five materials viz. polyurethane foam, polyester batting, polyester fabric, medium density fiberboard and oriented strand board that are used in the built environment. Subsequently using the properties, model the response of these materials to fire using the condensed phase solver in the numerical solver Fire Dynamics Simulator (FDS) developed by National Institute of Standards and Technology (NIST) with flame heat feedback application. Heat flow meter (HFM) and Integrating sphere were utilized to measure thermal conductivities and emissivity values for the materials. Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), Microscale Combustion Calorimetry (MCC) tests were carried out to develop a pyrolysis model and present reaction mechanism. Kinetic parameters were determined using inverse analysis with the Kinetics Neo (NETZSCH GmbH) software and the properties were used to populate the one-dimensional cone model. Flame heat feedback was applied to the model to determine the suitability of model to predict the heat release rate and compared against the cone calorimeter test data.Item Pyrolysis of Reinforced Polymer Composites: Parameterizing a Model for Multiple Compositions(2015) Martin, Geraldine Ellen; Stoliarov, Stanislav I; Fire Protection Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)A single set of material properties was developed to describe the pyrolysis of fiberglass reinforced polyester composites at multiple composition ratios. Milligram-scale testing was performed on the unsaturated polyester (UP) resin using thermogravimetric analysis (TGA) coupled with differential scanning calorimetry (DSC) to establish and characterize an effective semi-global reaction mechanism, of three consecutive first-order reactions. Radiation-driven gasification experiments were conducted on UP resin and the fiberglass composites at compositions ranging from 41 to 54 wt% resin at external heat fluxes from 30 to 70 kW m-2. The back surface temperature was recorded with an infrared camera and used as the target for inverse analysis to determine the thermal conductivity of the systematically isolated constituent species. Manual iterations were performed in a comprehensive pyrolysis model, ThermaKin. The complete set of properties was validated for the ability to reproduce the mass loss rate during gasification testing.Item A Generalized Model for Wall Flame Heat Flux During Upward Flame Spread on Polymers(2015) Korver, Kevin; Stoliarov, Stanislav; Fire Protection Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)A current model accurately predicts flame to surface heat flux during upward flame spread on PMMA based on a single input parameter, the mass loss rate. In this study, the model was generalized to predict the heat flux for a broad range of polymers by adding the heat of combustion as a second input parameter. Experimental measurements were conducted to determine mass loss rate during upward flame spread and heat of combustion for seven different polymers. Four types of heat of combustion values were compared to determine which generated the most accurate model predictions. The complete heat of combustion yielded the most accurate predictions (± 4 kW/m2 on average) in the generalized model when compared to experimental heat flux measurements collected in this study. Flame heat flux predictions from FDS direct numerical simulations were also compared to the generalized model predictions in an exploratory manner and found to be similar.Item Development of a Model for Flaming Combustion of Double-Wall Corrugated Cardboard(2012) McKinnon, Mark; Stoliarov, Stanislav I; Fire Protection Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Corrugated cardboard is used extensively in a storage capacity in warehouses and frequently acts as the primary fuel for accidental fires that begin in storage facilities. A one-dimensional numerical pyrolysis model for double-wall corrugated cardboard was developed using the Thermakin modeling environment to describe the burning rate of corrugated cardboard. The model parameters corresponding to the thermal properties of the corrugated cardboard layers were determined through analysis of data collected in cone calorimeter tests conducted with incident heat fluxes in the range 20-80 kW/m2. An apparent pyrolysis reaction mechanism and thermodynamic properties for the material were obtained using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The fully-parameterized bench-scale model predicted burning rate profiles that were in agreement with the experimental data for the entire range of incident heat fluxes, with more consistent predictions at higher heat fluxes.