Structural damage identification through variations in modal quantities using modal strain energy and mode shape curvature methods

Damage identification in engineering disciplines such as mechanical, civil, and aerospace engineering has become a critical area of research. This study introduces a methodology to address structural damage-induced loss of stiffness. The approach assumes that structures exhibit linear elastic behavior before and after the damage and considers them time-invariant. To demonstrate the applicability of the proposed method, a representative beam structure is selected to mimic various components found in buildings, bridges, and dams. The methodology involves developing a numerical model using the finite element (FE) method in ANSYS and a program developed in MATLAB. Additionally, experimental data is collected using vibrational transducers. The classical modal strain energy and mode shape curvature methods are compared to identify structural damage. The extent of this damage is determined by analyzing modal frequencies using a combined numerical and experimental approach. A modal assurance criterion is employed to gauge the similarity of mode shapes. The analytical FE model is refined through a direct model updating procedure using MATLAB scripts. In this iterative process, the numerical parameters of the FE model are fine-tuned to align more closely with the experimental data, ensuring the model accurately represents the real structure. This study combines experimental data with the improved numerical FE model to identify and quantify damage by measuring the loss of stiffness. Integrating expert knowledge and feedback into the model updating process, it can enhance the accuracy and interpretability of updated models.