Life Consumption Monitoring for Electronics

Abstract

Life consumption monitoring is a method to assess product's reliability based on its remaining life in a given life cycle environment. The life consumption monitoring process involves continuous or periodic measurement, sensing, recording, and interpretation of physical parameters associated with a system's life cycle environment to quantify the amount of degradation. This thesis explains a life consumption monitoring methodology for electronic products, which includes failure modes, mechanisms and effects analysis (FMMEA), virtual reliability assessment, monitoring product parameters, data simplification, stress and damage accumulation analysis and remaining life estimation. It presents two case studies to estimate the remaining life of identical circuit card assemblies in an automobile underhood environment using the life consumption monitoring methodology. Failure modes, mechanisms, and effects analysis along with virtual reliability assessment is used to determine the dominant failure mechanism in the given life cycle environment. Temperature and vibration are found to be the environmental factors, which could potentially cause malfunction of the circuit card assembly through solder joint fatigue. Temperature sensor and accelerometers are used along with a data logger to monitor and record the environmental loads during the experiment. A data simplification scheme is used to make the raw sensor data suitable for further processing. Stress and damage models are used to estimate the remaining life of the circuit card assembly based on the simplified data. Performances of the test board assemblies are monitored through resistance monitoring. The life cycle environment and results for the case studies are compared with each other. The estimated results are also compared with experimental life results.