An optic-fiber based dynamic pressure sensor is described here to measure weight-in-motion of vehicles. In the research reported herein, a Michelson interferometer with specially designed hardware and software were developed and experimentally subjected to dynamic compressive loads of different magnitudes, and loading rates. Experiments showed that both output fringe number and fringe period could be used to indicate the dynamic load. A calibration technique was put forward to calibrate the sensor. Both the dynamic weight and static weight of the vehicle passed can be obtained. The findings that resulted from these studies developed an understanding for the behavior of interferometer sensor under dynamic compressive states of stress and are fundamental to the application of fiber optic sensors for the monitoring of truck vehicle weights while in motion.

This study focuses on an active monitoring method for damage detection applied to composite structures. Honeycomb sandwich and carbon fiber composite structures are studied. Two kinds of damage are considered: delamination and impact damage. Wavelet analysis methods are adopted to postprocess the raw monitored signal. A new damage signature is introduced to determine the presence and extent of damage in composites, while eliminating the influence of different distances between the active actuator and active monitoring elements. The proposed method is shown to be effective, reliable, and straightforward for the specimens considered in the present study, which are composed of different materials and suffer various levels of damage. An online real-time active monitoring system for damage detection is described that is based on this research.