Study on the influence regulations of noise on the curvature mode in damage detections

Curvature mode can be written as second-order differentials and can be obtained by displacement mode using the center differential principle. Noise may cause vibration mode monitoring error, which can be transmitted to curvature mode. In order to study the effect of noises on the curvature mode analysis, the vibration mode data obtained from the finite element analysis are added the different level noises. The results indicate that the curvature mode method can accurately judge out the stiffness damages which are greater than 10 percent before the noises are introduced to the vibration mode, when the vibration displacement error caused by noises is higher 5 percent, the careless mistakes are easy to occur. Based on the concept of function total differential, the error transmission formulas from vibration mode to the curvature mode are derived.