Equivalent neutral axis for structural condition assessment using multi-sensor fusion

Damage detection is one of the primary purposes of structural health monitoring. Since neutral axis location changes have been considered to be sensitive damage indicators, extensive research efforts have been devoted to developing effective and accurate neutral axis estimation methods, although challenges remain in real-world applications. This study proposes a novel structural condition assessment method using an equivalent neutral axis (ENA) that can be estimated based on acceleration and strain measurements at each location where a sensor is installed. Numerical simulations were conducted using a simply supported steel beam model to investigate the effect of the ENA with respect to the sensor configuration and damage level. The proposed method was also applied to a numerical reinforced concrete beam model to further validate the ENA as a damage indicator, thus proving the sensitivity of the ENA to structural damage.