ARVC will develop portable, reliable, and easily operated instrumentation for reliable tension measurement in critical bolts, based on correlation and other mathematical and physical techniques. Specifically, we will combine multiple mathematical algorithms including cross-correlation and phase-slope delay determination with improved transducers and electronics having multifrequency and/or chirp capability in order to increase the number of ultrasonic echo time determination modalities, and thus increase the reliability of the time measurements and the consequent estimations of bolt tension. We will incorporate temperature measurement into the ultrasonic transducer to increase the reliability and user-friendliness of the overall system. We expect to greatly increase the accuracy and performance reliability of ultrasonic bolt tension measurements, as well as the ease of use of the instrument itself. The resulting instrument will find application throughout NASA and all of industry, and its benefits will be improved accuracy and reliability of tension measurement in critical fasteners.
