Smaaatav task order - statement of work (SOW) - task title: universal common practice guide to conduct lightning energy transfer characterizations 1.0 introduction/background: the growing…

Smaaatav task order - statement of work (SOW) - task title: universal common practice guide to conduct lightning energy transfer characterizations 1.0 introduction/background: the growing application of composite materials in commercial aircraft manufacturing has significantly increased the risk of aircraft damage from lightning strikes. With this growth in composite usage, new technical challenges arise. Composite skinned aircraft are far more vulnerable to damage from lightning strikes than their aluminum skinned predecessors and new mitigation strategies and engineering practices are required to maintain the same level of safety and protection as achieved by conductive aluminum skinned aircraft. The electrical current incident on an aircraft from a typical lightning strike can exceed 200,000 amperes , occurring in less than a fraction of a second. Without proper lightning strike protection, carbon fiber/epoxy and dielectric composites can be significantly damaged, particularly at the entry and exit points of the strike. Approaches have been developed to protect the composite structures from lightning direct effects to reduce damage to acceptable levels by using conductive foils or meshes in the outer layer of the composite system. When a known lightning strike occurs, the points of attachment and detachment on the aircraft surface must be found by visual inspection, and then assessed for damage by maintenance personnel to ensure continued safe flight operations. Repairs may be required to replace damaged composite sections per federal aviation administration (FAA) procedures . Often times, lightning damage is more severe than existing test standards would indicate, suggesting additional refinements are needed to fully represent the lightning environment. Lightning test standard waveforms are simplified laboratory-generated waveforms that represent key parameters including peak current, total energy transferred & signal rise time to simulate the statistical lightning environment established under previous society of automotive engineers (SAE) standard developments. To ensure flight safety, lightning strike protection (LSP) studies are conducted to gain FAA certification to show performance characteristics of the conductive layers placed over composite substrates and subjected to lightning direct effect electrical waveforms for flight safety air-worthiness standards testing. Test results are often incomparable due to variability in test procedures & practices between independent LSP studies. This prevents the ability to acquire performance correlations between different LSP data sets. A universal common practice procedure is needed to add conformity in future lightning strike protection evaluations to allow performance correlations across data sets. The NASA aviation safety program supports research directed to ensure future composite aircraft will survive lightning prone environments to safely navigate the national air space (NAS). Research to detect and mitigate lightning damage on composite aircraft is contained in the atmospheric environmental safety technology project managed at NASA glenn research center (GRC), which includes a NASA langley-led subproject titled atmospheric hazard safety mitigation (ahsm) led by robert neece. Project milestone AEST4.4.37 (atmospheric environment safety technologies) identifies research to develop a universal common practice procedure to perform standardized composite substrate lightning strike protection evaluations. This task will establish test procedures to develop energy-transfer characterizations through the real time monitoring of mechanical, thermal, and electrical energy transfers during plasma flashover arcing events and will develop the system requirements to safely monitor electrical current, temperature, and mechanical shock with adequate detection thresholds to support high fidelity modeling of composite structures for direct effect lightning d