Abstract: Systems, kits, and methods for testing a combustion arrester are disclosed. Systems include an upstream chamber, a downstream chamber, and a combustion arrester between the upstream chamber and the downstream chamber. The upstream chamber includes an ignition port configured to receive an ignition source. And, the upstream chamber defines a convergent duct that converges toward the combustion arrester and terminates at the combustion arrester. The upstream chamber may include a hierarchical series of modular shell sections that define the convergent duct. The downstream chamber may include a series of modular shell sections.

Abstract: Gas-flammability sensing systems and methods may be used to determine the flammability of gas mixtures in measurement volumes such as a fuel tank (e.g., an aircraft fuel tank). Gas-flammability sensing systems include a test cell structured to receive a gas sample, a heater in thermal communication with the test cell, and a gas meter configured to measure a physical property of the gas sample within the test cell related to the combustion state of the gas sample. The heater is configured to heat the gas sample to an elevated temperature less than the autoignition temperature of the gas sample. Methods of determining the flammability of a gas sample include collecting the gas sample, heating the gas sample to the elevated temperature, measuring the physical property of the gas sample after heating, and determining the flammability of a gas sample based upon the measured physical property.

Abstract: Ignition-quenching systems include an ignition-risk structure that extends from a support structure into a combustible environment and include a porous ignition-quenching cover that substantially covers the ignition-risk structure. The ignition-quenching cover is configured to quench an ignition event triggered by an ignition source associated with the ignition-risk structure. Ignition-quenching covers generally include a porous body. The porous body may include one or more porous elements. Methods according to the present disclosure include installing a porous ignition-quenching cover over an ignition-risk structure to prevent bulk combustion, e.g., of a fuel vapor in a fuel tank, due to an ignition event associated with the ignition-risk structure.

Abstract: Ignition-quenching systems comprise an ignition-quenching cover configured to quench an ignition event in a combustible environment triggered by an ignition source associated with a fastener stack. The ignition-quenching cover comprises a porous body that is gas permeable and that has pores sized to quench ignition in the combustible environment. The ignition-quenching cover further comprises a cover attachment feature configured to mate with a fastener attachment feature of the fastener stack. The ignition-quenching cover is configured to cover the fastener stack, which may be associated with a potential ignition source that produces an ignition event in the combustible environment. The porous body may include one or more porous elements that may be formed of various polymeric, mesh, or fabric materials. The ignition-quenching cover may comprise a non-porous frame that is bonded to the porous body and that defines the cover attachment feature.

Abstract: A combustion test system includes a power source and a corona generator coupled to the power source. The combustion test system also includes a charge storage device. The charge storage device includes a charging surface spaced apart from the corona generator such that charge carriers, motivated by an electric field of the corona generator, intersect the charging surface to charge the charge storage device. The combustion test system also includes a first electrode coupled to the charge storage device and a second electrode coupled to a reference ground. The second electrode is spaced apart from the first electrode to produce an electrical arc between the first electrode and the second electrode based on a voltage difference between the first electrode and the second electrode.

Abstract: Systems and methods for quantifying combustion arrester performance are disclosed. Methods include filling an upstream volume and a combustion arrester with a flammable gas, igniting the flammable gas in the upstream volume (and upstream of the combustion arrester), measuring a composition of gas discharged from the combustion arrester due to ignition of the flammable gas, and quantifying the performance of the combustion arrester based on the composition of gas measured. The measured gas composition may include types and/or amounts of combustion species within the gas discharged from the combustion arrester.

Abstract: An ignition testing system including a test article testing chamber, and at least one gas mixture verification chamber being communicably coupled to the test article testing chamber and being configured to verify at least a content of a gas mixture content provided to the test article testing chamber.

Abstract: Incendivity test systems and methods are disclosed. Incendivity test systems include a non-flammable gas mixture and a test article. The non-flammable gas mixture includes a thermally reactive reagent that is formulated to thermally react to produce a reaction product. Incendivity test systems also include an energy source configured to apply an energy discharge such as a simulated lightning strike to the test article. Incendivity test systems also include a detection device configured to measure an indicator species in the non-flammable gas mixture (e.g., the thermally reactive reagent and/or the reaction product). Incendivity test methods include contacting the test article with the non-flammable gas mixture, applying the energy discharge to the test article, and then measuring the amount of the indicator species and determining the incendivity of the test article in response to the energy discharge based upon the amount of the indicator species.

Abstract: Ignition-quenching systems comprise an ignition-quenching cover configured to quench an ignition event in a combustible environment triggered by an ignition source associated with a fastener stack. The ignition-quenching cover comprises a porous body that is gas permeable and that has pores sized to quench ignition in the combustible environment. The ignition-quenching cover further comprises a cover attachment feature configured to mate with a fastener attachment feature of the fastener stack. The ignition-quenching cover is configured to cover the fastener stack, which may be associated with a potential ignition source that produces an ignition event in the combustible environment. The porous body may include one or more porous elements that may be formed of various polymeric, mesh, or fabric materials. The ignition-quenching cover may comprise a non-porous frame that is bonded to the porous body and that defines the cover attachment feature.

Abstract: Incendivity test systems and methods are disclosed. Incendivity test systems include a non-flammable gas mixture and a test article in a test chamber. The non-flammable gas mixture includes a thermally reactive reagent that is formulated to thermally react to produce a reaction product. Incendivity test systems also include an energy source configured to apply an energy discharge such as a simulated lightning strike to the test article. Incendivity test systems also include a detection device configured to measure an indicator species in the non-flammable gas mixture (e.g., the thermally reactive reagent and/or the reaction product). Incendivity test methods include contacting the test article with the non-flammable gas mixture, applying the energy discharge to the test article, and then measuring the amount of the indicator species and determining the incendivity of the test article in response to the energy discharge based upon the amount of the indicator species.

Abstract: Disclosed are ignition source testing systems and methods that utilize a foam with flammable components to indicate the presence of an ignition source on a test article (such as metallic components of a fuel system). Foam is applied to the test article and an energy discharge (such as a simulated lightning strike) is applied to the test article with the foam. The energy discharge may create an ignition source (such as an arc) on the test article that is sufficient to ignite the foam. Test methods comprise determining whether the foam ignited in response to the energy discharge. Test systems comprise the foam, the test article at least partially covered by the foam, and an energy source configured to discharge energy into the test article.

Abstract: A conductive fiber reinforced polymer composition may include a composite structure having a longitudinal axis, a lateral axis, and a through axis, the composite structure including a polymer matrix, a conductive filler incorporated into the polymer matrix, and a reinforcing material incorporated into the polymer matrix.

Abstract: Systems, kits, and methods for testing a combustion arrester are disclosed. Systems include an upstream chamber, a downstream chamber, and a combustion arrester between the upstream chamber and the downstream chamber. The upstream chamber includes an ignition port configured to receive an ignition source. And, the upstream chamber defines a convergent duct that converges toward the combustion arrester and terminates at the combustion arrester. The upstream chamber may include a hierarchical series of modular shell sections that define the convergent duct. The downstream chamber may include a series of modular shell sections.

Abstract: Systems and methods for quantifying combustion arrester performance are disclosed. Methods include filling an upstream volume and a combustion arrester with a flammable gas, igniting the flammable gas in the upstream volume (and upstream of the combustion arrester), measuring a composition of gas discharged from the combustion arrester due to ignition of the flammable gas, and quantifying the performance of the combustion arrester based on the composition of gas measured. The measured gas composition may include types and/or amounts of combustion species within the gas discharged from the combustion arrester.

Abstract: Gas-flammability sensing systems and methods may be used to determine the flammability of gas mixtures in measurement volumes such as a fuel tank (e.g., an aircraft fuel tank). Gas-flammability sensing systems include a test cell structured to receive a gas sample, a heater in thermal communication with the test cell, and a gas meter configured to measure a physical property of the gas sample within the test cell related to the combustion state of the gas sample. The heater is configured to heat the gas sample to an elevated temperature less than the autoignition temperature of the gas sample. Methods of determining the flammability of a gas sample include collecting the gas sample, heating the gas sample to the elevated temperature, measuring the physical property of the gas sample after heating, and determining the flammability of a gas sample based upon the measured physical property.

Abstract: Methods of incendivity testing include applying a flexible sheet over a test article to form a sealed space between the flexible sheet and a surface region of the test article. Methods further include filling the sealed space with an indicator gas mixture, applying an energy discharge to the test article, and determining whether the indicator gas mixture in the sealed space reacted in response to the energy discharge. The indicator gas mixture may be flammable and may be formed while filling the sealed space. Incendivity test systems include the test article, the flexible sheet sealed to the test article to form the sealed space, a gas control module configured to fill, flush, purge, and/or sample gas in the sealed space, and an energy source configured to apply the energy discharge to the test article.

Abstract: Incendivity test systems and methods are disclosed. Incendivity test systems include a non-flammable gas mixture and a test article in a test chamber. The non-flammable gas mixture includes a thermally reactive reagent that is formulated to thermally react to produce a reaction product. Incendivity test systems also include an energy source configured to apply an energy discharge such as a simulated lightning strike to the test article. Incendivity test systems also include a detection device configured to measure an indicator species in the non-flammable gas mixture (e.g., the thermally reactive reagent and/or the reaction product). Incendivity test methods include contacting the test article with the non-flammable gas mixture, applying the energy discharge to the test article, and then measuring the amount of the indicator species and determining the incendivity of the test article in response to the energy discharge based upon the amount of the indicator species.

Abstract: A method, apparatus, and composite fuel tank for manufacturing a structure is provided. A first composite layer and a second composite layer are placed on a mold. The second composite layer and the first composite layer are cured. The first composite layer and the second composite layer form the structure. The second composite layer is configured to dissipate an electric charge on a surface of the structure.

Abstract: Disclosed are ignition source testing systems and methods that utilize a foam with flammable components to indicate the presence of an ignition source on a test article (such as metallic components of a fuel system). Foam is applied to the test article and an energy discharge (such as a simulated lightning strike) is applied to the test article with the foam. The energy discharge may create an ignition source (such as an arc) on the test article that is sufficient to ignite the foam. Test methods comprise determining whether the foam ignited in response to the energy discharge. Test systems comprise the foam, the test article at least partially covered by the foam, and an energy source configured to discharge energy into the test article.

Abstract: Systems and methods for ignition source testing with a flammable foam are disclosed. Flammable foam systems and methods for testing use a flammable foam that includes fuel and oxidant. Flammable foam is applied to a test article and an energy discharge is applied to the test article. Methods include determining whether the flammable foam ignited in response to the energy discharge.