A Methodology for Structural Damage Detection Adding Masses

ABSTRACT

In engineering applications, it is standard to consider modal parameters (e.g. natural frequencies and mode shapes), to obtain measurable changes induced by damage events. However, such changes are often too subtle to detect and interpret accurately. In order to overcome this limitation and enhance the efficacy of damage detection, this study introduces an innovative technique inspired by Prof. Lekszycki, outlined prior to his untimely departure. This technique is designed to highlight the influence of structural damage on natural frequencies. In other words, we add an external mass in a general point of a structure and calculate the set of natural frequencies before and after the occurrence of a damage event. We, therefore, repeat this procedure for all the points of the structure. The hypothesis we have verified in this paper is that if the mass is posed in the neighborhood of the place where the damage is considered, then it interacts with the undamaged and with the damaged structure in a different way. In particular, the changes of the natural frequencies between the undamaged and the damaged structure are emphasized. We verify the correctness of this idea for selected and simple examples in both 2D and 3D environments.

KEYWORDS:

• Damage identification
• damage detection
• structural dynamics

Acknowledgments

Funds used for the analysis and the writing of this paper were provided by Uninettuno University. Dlubal Software is thanked for the academic license of RFEM 6.

The present work is dedicated to the memory of Prof. Tomasz Lekszycki, who recently died. The idea at the basis of this work belonged in fact to him. He has shared these ideas (sharing his scientific ideas always distinguished him) with the third author in the spring of 2018, during a visit to Warsaw for a course for the student of the Warsaw University of Technology.

Disclosure statement

No potential conflict of interest was reported by the author(s).