The purpose of this paper is to develop a better understanding of the mechanism of failure of structures and to develop and test the new Cross Random Decrement method for the early detection, identification and location of damages. An experimental study has been conducted on a scale model offshore platform structure. The dynamic responses of the platform under single impact and random excitation were measured for three damage senarios. The response signals were first analyzed using an FFT spectrum analyzer which gives the transfer functions. The changes in the modal parameters such as frequencies and dampings indicate the severeness of the structural damage. For the case of random excitation, system's modal information were obtained from its time signature. Random decrement signal processing technique combined with proper filtering process was used. The changes in the time signatures were correlated with the progressive severeness of the structure damage. A cross random decrement signal processing technique has also been investigated. The time signatures resulting from the cross random decrement process provide information concerning the time lag between the responses of the two different locations in the structure when it is randomly excited. This information was used in the determination of the location of the damage.
Detection of damages in structures by the cross random decrement method
Bestimmung von Beschaedigungen in Strukturen mit der Kreuz-Zufallsdekrement-Methode
IMAC 3. Proc. of the 3rd Int. Modal Analysis Conf., Union College-Schenectady ; 2 , Jan ; 691-700
1985
10 Seiten, 12 Bilder, 3 Tabellen, 4 Quellen
Conference paper
English
MODALANALYSE , MATHEMATISCHES MODELL , MATHEMATISCHE TRANSFORMATION , FOURIER-TRANSFORMATION , MODELLUNTERSUCHUNG , OFFSHORE-PLATTFORM , KONSTRUKTIONSDATEN , VERSAGENSART , FEHLERERKENNUNG , FEHLERANALYSE , FEHLERORTUNG , SCHWINGUNGSSYSTEM , DYNAMISCHES VERHALTEN , SCHWINGUNGSSPEKTRUM , FREQUENZGANG , RESONANZFREQUENZ , FINITE-ELEMENTE-METHODE , SIGNALUMSETZUNG , ZUFALLSZAHL