Damage Propagation Assessment - A Causal Model Approach for Design and Operations

Qualtech Systems, Inc. (QSI) in collaboration with Dr. Stephen B. Johnson of Dependable Systems Technologies (DST) proposesnbsp;a novel, causal-model based systematic methodology for assessing damage propagation due to one or multiple originating faults and how the propagation affects and damages other components. In fault propagation, downstream components from the root-cause fault which rely on its function, may also fail. When the root cause is mitigated, those downstream components resume their normal operating behavior. During damage propagation, the originating faultrsquo;s damage, leads to the failure effects in which physical damage to downstream components is a consequence, such that those components can no longer function nominally. Even if the originating fault recovers or is replaced or bypassed, the downstream damaged components do not recover and continue to remain in a failed state. nbsp;nbsp; This proposal aims to create new capabilities for QSIrsquo;s TEAMSreg; tool suite to represent the differences between components in which failure effects lsquo;pass throughrsquo; or cause only functional impairment versus those that can cause physical damage. During TEAMSreg; model design, this new capability will enable the modeler to represent the activation of a downstream component failure mode when a specific failure effect (a TEAMSreg; lsquo;functionrsquo;) arrives at the component. This will signify that though the failure effects begin with a single fault (cause, failure mode), a second fault will now exist in the relevant downstream component so that if the first fault is removed the second fault will remain unless another repair is made. During operations when TEAMSreg; is used to perform diagnosis, TEAMSreg; will alert operators that a second independent fault may exist as a consequence of the effects of the first fault. The impact of this new capability on the TEAMSreg; fault management metrics modeling and generation capability will be explored during the course of the SBIR project.