Identifying damage at an early stage is crucial for preserving the integrity of structures. Damage in structures often manifests as adverse changes within the system, which can propagate over time and ultimately lead to structural failure. This research introduces a novel damage index, referred to as the P-Index, for detecting damage in beam-type structures. The P-Index is developed using the Reduced Interference Distribution—a bilinear time-frequency function—along with matrix expansion techniques. Tovalidate the effectiveness of the proposed method, laboratory tests were conducted on a steel beam. The results demonstrate the capability of the P-Index to accurately identify damage. Key advantages of this method include high accuracy, ease of implementation, no requirement for input force measurement, reduced sensor usage, and the ability to work with recorded signals without noise removal.
