NATURAL FREQUENCY BASED STRUCTURE DAMAGE DETECTION METHOD

摘要

PURPOSE: A method of detecting the damage of a structure based on natural frequency is provided to determine the operating state of a machine and to detect the damage of a structure with a vibration experiment value only measured at the outer surfaces of the structure and the machine. CONSTITUTION: A method of detecting the damage of a structure based on natural frequency is as follows. The ratio of the natural frequency before the damage of a structure to that depending on the changes of the position and size of the damage after damage is calculated. The position, size and direction of the damage of the structure are detected using the natural frequency ratio. The method calculates the rigidity variation using a frequency response function. As the damage size becomes bigger and the damage position becomes closer to a fixed end, the natural frequencies before/after damage change to a considerable level.