A structural-health-monitoring system can contribute to the risk management of a structure operating under hazardous conditions. An example is the wing leading-edge impact-detection system that monitors the debris hazards to the Space Shuttle Orbiter's reinforced carbon-carbon panels. Since return to flight after the Columbia accident, the system was developed and subsequently deployed on board the orbiter to detect ascent and on-orbit debris impacts, so as to support the assessment of wing leading edge structural integrity before orbiter reentry. As structural health monitoring is inherently an inverse problem, the analyses involved, including those performed for this system, tend to be associated with significant uncertainty. The use of probabilistic approaches to handle the uncertainty has resulted in the successful implementation of many development and application milestones. Nomenclature d = damage size, in. G max = maximum acceleration response G rms = rms of acceleration response P = damage probability P C = joint probability of critical damage P C=I = conditional probability of critical damage given an impact has occurred P F = probability of multisensor corroboration being weaker than flight experience P I = probability of impact P M = probability of multisensor corroboration being stronger than model experience r diag = diagonal corroboration ratio of multisensor response r horz = horizontal corroboration ratio of multisensor response = logarithmic decay dam = damage-G max correlation factor mea = test measurement scaling factor pan = reinforced carbon-carbon panel-to-panel test scaling factor sen = sensor configuration test scaling factor tst = test-article boundary condition scaling factor

A structural health monitoring (SHM) system can contribute to the risk management of a structure operating under hazardous conditions. An example is the Wing Leading Edge Impact Detection System (WLEIDS) that monitors the debris hazards to the Space Shuttle Orbiter's Reinforced Carbon-Carbon (RCC) panels. Since Return-to-Flight (RTF) after the Columbia accident, WLEIDS was developed and subsequently deployed on board the Orbiter to detect ascent and on-orbit debris impacts, so as to support the assessment of wing leading edge structural integrity prior to Orbiter re-entry. As SHM is inherently an inverse problem, the analyses involved, including those performed for WLEIDS, tend to be associated with significant uncertainty. The use of probabilistic approaches to handle the uncertainty has resulted in the successful implementation of many development and application milestones. NomenclatureG max = Maximum acceleration response G rms = Root-mean-square of acceleration response δ = Logarithmic decay P = Damage probability P I = Probability of impact P C = Joint probability of critical damage P C/I = Conditional probability of critical damage given an impact has occurred P M = Probability of multi-sensor corroboration being stronger than model experience P F = Probability of multi-sensor corroboration being weaker than flight experience r diag = Diagonal corroboration ratio of multi-sensor response r horz = Horizontal corroboration ratio of multi-sensor response λ sen = Sensor configuration test scaling factor λ pan = RCC panel-to-panel test scaling factor λ tst = Test article boundary condition scaling factor λ mea = Test measurement scaling factor λ dam = Damage-G max correlation factor d = Damage size (inch)

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