MEASUREMENT OF REFLECTED AND SCATTERED-LIGHT FOR MONITORING FLUCTUATION OF STRUCTURES

A laser spectroscopic technique for studying fluctuations of structura l objects is presented, together with some results of our investigatio ns including an observation of forced vibration of a refrigerator, int rinsic vibrations of buildings, and appearance of a fluctuation in rot ational speed due to fatigue. An alternative detection technique which uses the scattered light for monitoring in place of the mirror-reflec ted beam is also presented. A leak of water out of a pipeline was dete cted with this method. The results obtained with this laser spectrosco pic technique should form a useful collection of data regarding fluctu ation analysis of various objects.