Managing and Predicting Intermittent Failures Within Long Life Electronics

Many studies have confirmed that electronic failure is not a static or random event, but a process of material changes. These changes may not cause loss of operation for the electronic system, even when the components are technically out of specification. This self- compensating aspect of electronics makes diagnostics of failures particularly difficult and contributes to the ubiquitous problem of cannot duplicate (CND) failures. In addition to self-compensation, degraded failure modes of components manifest in different operating conditions and may offset one another depending on circuit configuration.12 With these considerations, VEXTEC is developing an intermittent fault reduction methodology which considers the material changes in the electronic components on the circuit board and provides a probability of true fault when a fault is detected by built in test (BIT). By modeling the electronics as a system rather than focusing on individual components, VEXTEC can model an entire circuit board with a standard library of models as part of the OEM´s normal design cycle. The model is then used with the off board PHM (Prognostics and Health Management) system within a vehicle or other high reliability electronic system to predict the probabilities of intermittent failure. This modeling capability has far reaching effects on the diagnostics and prognostics of an electronic system. The operators can manage the fleet by risk rather than by guessing the level of degradation or when intermittent failures will occur. Organizations responsible for quality, maintenance and repair can minimize the impact of CND faults on the supply chain and on troubleshooting. The order of components replaced during a fault event can even be prioritized according to the probabilities provided by this algorithm.