Author(s)

H. Fang

Abstract

This paper presents an improved method for the damage severity estimate for lattice structures based on the employment of the substructure modal strain energy (SMSE). The significant advantage associated with the improved method over traditional modal energy methods is that it can directly use the mode shape of the damaged element to quantify damage severity exactly. Additionally, the new method does not require the analytical and measured modes to be consistent in scale, or to be normalized. Numerical studies in this paper are conducted for a three-dimensional frame structure based on synthetic data generated from finite element models. Keywords: damage quantification, substructure energy, modal analysis. 1 Introduction The properties of the truss material that appear most attractive are those that govern the use of the truss as cores for sandwich structures as having lower weight than competing materials, and potentially superior heat dissipation, vibration control and energy dissipation characteristics [1]. The mechanical properties of lattice structures may degrade severely in the presence of damage. Structural damage often occurs in one or more elements of a structure with a loss of stiffness. These changes in structural properties in turn alter the dynamic response behaviour of the structure from its pre-damage condition. Therefore, it is common to monitor structural health condition using data obtained from an associated vibration testing. A number of approaches to the damage severity quantification exist [2]. The modal testing and analysis method seeks to determine the modal parameters,

Keywords

damage quantification, substructure energy, modal analysis