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A new energy indicator in damage locating vector method ((DLV) for detecting multiple damaged positions in beam and truss structures

The paper presents a new indicator called normalized energy index (nei) in damage locating vector method (DLV) for detecting multiple damaged positions in beam and truss structures. In the DLV method, a set of load vectors, which is extracted from the change in flexibility matrix between an undamaged structure and a damaged one, is applied as static loads to the undamaged structure which are evaluated via the finite element modeling. | Vietnam Journal of Mechanics, VAST, Vol. 38, No. 3 (2016), pp. 153 – 166 DOI:10.15625/0866-7136/38/3/5807 A NEW ENERGY INDICATOR IN DAMAGE LOCATING VECTOR METHOD (DLV) FOR DETECTING MULTIPLE DAMAGED POSITIONS IN BEAM AND TRUSS STRUCTURES Nguyen Minh Nhan1 , Dinh Cong Du1 , Vo Duy Trung1 , Tran Viet Anh1 , Nguyen Thoi Trung2,∗ 1 Ton Duc Thang University, Ho Chi Minh City, Vietnam 2 University of Science, Vietnam National University - Ho Chi Minh City, Vietnam ∗ E-mail: thoitrung76@gmail.com Received January 08, 2015 Abstract. The paper presents a new indicator called normalized energy index (nei) in damage locating vector method (DLV) for detecting multiple damaged positions in beam and truss structures. In the DLV method, a set of load vectors, which is extracted from the change in flexibility matrix between an undamaged structure and a damaged one, is applied as static loads to the undamaged structure which are evaluated via the finite element modeling. Then, the nei values are computed for each element by using the displacements. In order to verify the accuracy and efficiency of a proposed indicator, a cantilevered beam and a 14-bay planar truss are considered. Keywords: Damage locating vector method (DLV), strain energy, load vector, damage detection, vibration. 1. INTRODUCTION Structural health monitoring (SHM) is being considered as a promising field when the safety of structures is considered in construction engineering. In SHM, it is important to detect the location of the damage as well as its extent. In numerical simulation, the damage in structures is usually simulated as the reduction of elemental stiffness. The weakening of structural members usually comes along with the changes in dynamic characteristics of structures which compose of frequencies and mode shapes. These characteristics are usually captured in a vibrating structure which is excited by either wind, or moving vehicle, earthquake or shaker. Based on the modal properties, scientists .