Damage Detection of Functionally Graded Euler-Bernoulli Beam Based on Element Modal Strain Energy Equivalence Index

Modal strain energy has been widely utilized in structural damage detection for its excellent performance. Based on the element modal strain energy equivalence index, a damage identification method for functionally graded Euler-Bernoulli beam is proposed in this paper. The damage index is obtained based on the change of element modal strain energy before and after the occurrence of damage and the theory of dissipation ratio of modal strain energy. Numerical examples of a simply-supported and a continuous functionally graded Euler-Bernoulli beam are studied to demonstrate the efficiency of the method. The effects of gradient index, damage extent, the order of mode shape and noise level are investigated respectively. It is demonstrated that the proposed method has very good capability for identifying damage locations and extent, also has excellent resistance to measurement noise.