Hybrid Simulation Testbed for Experimental Validation and Characterization of NDE and Sensor Technology

Abstract

An increasing number of online structural health monitoring systems have been implemented on bridges, which are often comprised of a variety of local sensing and nondestructive evaluation (NDE) devices. However, before any new type of sensor and NDE technology, such as ultrasonic surface wave sensors, can be deployed for field implementation, they first need to be validated and characterized under realistic loads and environmental conditions in a controlled laboratory setting. This paper demonstrates the use of a hybrid testing setup to create a characterization testbed for more realistic evaluation of NDE and sensor technologies. A prototype bridge structure based on the Yellow Mill Pond Bridge in Connecticut was selected to demonstrate the features and issues of a hybrid simulation testbed for sensor characterization, such as flexibility in traffic load representation, and large-scale specimens even with small testing equipment. Using this prototype bridge structure, a series of hybrid simulation tests using real variable-amplitude traffic loading were performed on a 0.6-scale steel flange plate specimen with a welded cover plate. Features of this hybrid simulation testbed are discussed, including the complexity of the virtual model (e.g., the dynamic mass effects and damping of the structure) and stability issues that can develop in the test. Finally, the ability of the hybrid testing platform to evaluate sensor performance under varying environmental conditions was demonstrated for elevated temperatures. Although a strain gauge was used to demonstrate the technology, the sensor testbed can be used for general characterization of other types of NDE devices and sensors.