SOUTHWEST RESEARCH INSTITUTE

		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:

• Power generation

• Aerospace

• Oil, gas, and petrochemical

• Manufacturing and transportation

• Medical devices

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

• Microscopy

• Mounted cross sectioning

• Unmounted cross sectioning

• Plasma etching

• Wet-chemical etching

• Material removal

• Microprobing

• Hermeticity testing

• Wire-bond strength measurement

• Particle-impact-noise detection

Failure Prevention of Structural Components

The causes of catastrophic failure are isolated using systematic failure analysis of:

• Compressor components

• Diesel engine components

• Aircraft structures

• Heat exchangers

• Pressure vessels

• Piping

• Medical devices

Root Cause Failure Diagnosis

Investigations of blading, bearings, combustors, and other gas turbine components combine the technologies of:

• Fractographic examination

• Materials evaluation

• Structural analysis

• Dynamic loading

• Thermal environment prediction

• Fracture mechanics analysis

• Frequency testing

Failure Analysis Contact Information

For more information about electronic and electrical component failure analysis capabilities at SwRI or how you can contract with SwRI, please visit the Electronic and Electrical Component Analysis website or contact Stan Silvus at ssilvus@swri.org or (210) 522-2742, or Ken Bennett at kbennett@swri.org or (210) 522- 5242.

For more information about failure prevention of structural components capabilities at SwRI or how you can contract with SwRI, please visit the Failure Prevention of Structural Components website or contact Richard A. Page, Ph.D., at rpage@swri.org or (210) 522-3252, or N. Sastry Cheruvu, Ph.D., at scheruvu@swri.org or (210) 522-2492.

For more information on the structural system and component failure analysis capabilities at SwRI or how you can contract with SwRI, please visit the Structural System and Component Failure Analysis brochure or contact Richard A. Page at rpage@swri.org or (210) 522-3252.

For more information on the root cause failure diagnosis capabilities at SwRI or how you can contract with SwRI, please visit the Root Cause Failure Diagnosis web page of the Gas Turbine Technology Center web site or contact Klaus Brun, Ph.D. at kbrun@swri.org or (210) 522-5449.

failureanalysis.swri.org

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Southwest Research Institute^® (SwRI^®), headquartered in San Antonio, Texas, is a multidisciplinary, independent, nonprofit, applied engineering and physical sciences research and development organization with 11 technical divisions.

December 28, 2012