page_title: Electrochemical fatigue crack sensor
section_title: History
hierarchical_section_title: Electrochemical fatigue crack sensor / History
context_page_description: An Electrochemical Fatigue Crack Sensor 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.
context_section_description: 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.
caption: The Electrochemical Fatigue Crack Sensor.