The objective of this work is to develop a damage detection algorithm, which is based on experimentally identified data and a mathematical relation between the damage information and the changes in structural dynamic characteristics. The relation is derived in the form of a differential equation, which relate the damage information, natural frequency changes, and the modes of the undamaged and damaged structure. The curvature mode is chosen in this method due to its sensitivity to the presence of the damage and its localized information. The detection algorithm enables one to locate the damages and to obtain the corresponding magnitudes simultaneously. For illustration of the methods numerical simulation on damaged beams were conducted. The damages were considered as point damages. Numerical simulation results are presented.