Normal wear out of the contact-arm pivot in this snap-action switch diverted some of the load current through the spring in the over-center mechanism. Joule heating raised the temperature of the spring high enough to melt the thermoplastic
actuator, thus allowing the spring to move into a neutral position that disabled the over-center snap action and made the switch inoperative.
For life assessment studies, staff members perform
fractography on critical aircraft structures, such as this wing spar, to identify crack
initiation sites and growth rates.
Using a scanning electron microscope equipped with a servo-hydraulic loading stage, SwRI can perform controlled crack growth studies at high magnifications, as well as determine fracture
morphologies and microstructural anomalies of failed components.
Failed blade examination by SwRI engineers revealed crack initiation by environment attack and propagation by high-cycle fatigue.
For more than 50 years, Southwest Research Institute (SwRI) has served industry and government in investigating mechanical, structural, electrical, and electronic component failures.
Purpose of Failure Analysis
Failure analysis can help isolate the causes of catastrophic failures and identify a root cause or causes, and, as a result, recommendations to prevent
future problems can be made. The SwRI Materials Engineering Department specializes in failure analysis for several industries including:
Oil, gas, and petrochemical
Manufacturing and transportation
Since 1978, SwRI has also performed failure analysis and construction analysis of electronic and electrical components. SwRI's Electronic and Electrical Component Analysis Section provides failure analysis services to the automotive, computer, consumer
appliance, electric utility, electronic component, industrial control, petrochemical, and semiconductor industries.
Electronic and Electrical Component Analysis
Failure analysis and construction analysis of electronic and electrical components have been the primary emphases of the
SwRI Component Analysis group since 1978. Using specialized equipment, experienced analysts perform:
Package opening and decapsulation
Mounted cross sectioning
Unmounted cross sectioning
Wire-bond strength measurement
Failure Prevention of Structural Components
The causes of catastrophic failure are isolated using systematic failure analysis of:
Diesel engine components
Root Cause Failure Diagnosis
Investigations of blading, bearings, combustors, and other gas turbine components combine the
Southwest Research Institute® (SwRI®), headquartered
in San Antonio, Texas, is a multidisciplinary, independent, nonprofit, applied
engineering and physical sciences research and development organization with