C06-28: Integrated Health and Usage Monitoring System
Objective:
To develop a method for in-situ health assessment of electronic boards
subjected to vibration and shock loads, and demonstrate the methodology on the
test board used in the C05-28 project.
Background:
Health monitoring is a process of observing and recording the extent of
deviation or degradation from an expected normal operating condition. Health
monitoring methods include the use of fuses and sacrificial sensors (such as
canary devices), failure precursor monitoring and reasoning, and environmental
and usage load monitoring. The aim is to provide advance warning of failure,
prevent catastrophic failures, reduce unscheduled downtimes, improve
availability, enable fault diagnosis, and provide data for design use.
For the past five years, the CALCE EPSC has been conducting research on
health monitoring and prognostics of electronic systems. Project C99-43 analyzed
the underlying philosophies of available health and usage monitoring
technologies for use in monitoring the life consumption of electronic systems.
In C00-50 a methodology to use CALCE physics-of-failure (PoF) method for life
consumption monitoring (LCM) was developed. Project C01-19 demonstrated that
life consumption monitoring is possible in an automobile application. In C02-10,
two comparisons were conducted to assess the remaining life prediction through
LCM with actual life obtained from in-situ resistance monitoring. In C03-26
project, CALCE developed and integrated software modules for data collection,
simplification and damage accumulation for LCM. Also, the applicability of LCM
to electronic systems was enhanced by developing the FMMEA techniques to
identify the dominant failure mechanisms and select the parameters to be
monitored for health assessment.
In 2004, CALCE commenced a multiyear project to build an integrated
hardware-software solution that can enable health monitoring and prognostics of
electronics in its application environment. In the C04-19 project, a methodology
for assessing solder joint remaining life, based on monitoring and modeling of
environmental and usage data was developed. A test board was characterized to
assess solder joint failures under thermal cycling conditions using thermal
fatigue models and accelerated testing. Algorithms used for data reduction and
cycle counting were assessed to evaluate the impact of variations in measurement
interval and reversal elimination on accumulated damage.
In the C05-28 project, the test board characterized in C04-19 was subjected
to random temperature profiles with the board temperature response measured
in-situ. The measured data was converted into cycles using data reduction and
cycle counting algorithms. The damage incurred was assessed using thermal
fatigue models to predict the remaining life in near real time.
This project will extend the scope of health and usage monitoring to assess
solder joint fatigue failures due to vibration and shock loads. The aim of
vibration based health monitoring methods is to determine the presence of
damage, determine the geometric location of the damage, quantify the severity of
damage, and predict the remaining service life of the product. A broad range of
techniques, algorithms, and methods are available for health monitoring of
mechanical structures under vibrational loading. However, due to unique
challenges (in terms of miniature scale of defects) presented by electronic
products and systems, a direct application of these methods may not always
possible.
Approach:
A range of approaches will be investigated for health monitoring of
electronic boards under vibration and shock loading. Methodologies for sensing,
signal processing, and interpretation of measured vibration response will be
developed. This approach will incorporate existing vibration fatigue models for
electronics to estimate remaining life. The methodology will be validated using
the HUMS test board from C05-28.