Electrochemical fatigue crack sensor

An Electrochemical Fatigue Crack Sensor (EFCS) is a type of low cost electrochemical nondestructive dynamic testing method used primarily in the aerospace and transportation infrastructure industries. The method is used to locate surface-breaking and slightly subsurface defects in all metallic materials. In bridge structures, EFCS is used at known fatigue susceptible areas, such as sharp-angled coped beams, stringer to beam attachments, and the toe of welds. This dynamic testing can be a form of short term or long term monitoring, as long as the structure is undergoing dynamic cyclic loading.

The Electrochemical Fatigue Sensor (EFS) is the only Electrochemical Fatigue Crack Sensors (EFCS) on the market. Its history is below:

In 1992, Dr. Campbell Laird and Dr. Yuanfeng Li invented the EFS™. The EFS™ relies on a patented electrical test method, which monitors the current flow at the surface of a metal while it is being mechanically flexed. The output current resembles a heart’s EKG pattern and can be interpreted to indicate the degree of fatigue as well as the presence of cracks in their earliest stages of development. The technology behind EFS was devised by researchers from the U.S. Air Force and the University of Pennsylvania for use in the aerospace industry. The original research was aimed at developing a technology for detecting problem cracks in airframes and engines. Since that time, additional research and development has resulted in the adaptation of the EFS system for steel bridge inspection.

The Electrochemical Fatigue Sensor (EFS) is a nondestructive crack dynamic inspection technology, similar in concept to a medical EKG, which is used to determine if actively growing fatigue cracks are present. An EFS sensor is first applied to the fatigue sensitive location on the bridge or metal structure, and then is injected with an electrolyte, at which point a small voltage is applied. The system subsequently monitors changes in the current response that results from the exposure of fresh steel during crack propagation. The EFS system consists of an electrolyte, a sensor array and a modified potentiostat call the potentiostat data link (PDL) for applying a constant polarizing voltage between the bridge and sensor, as well as data collection and analysis software.

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