Studying the changes of mechanical performance for damaged structures and components have widely drawn the interests of researchers in the world. One can find that from the literature

most of the researchers in this field study damages of the structures according to the theory of equivalent strain based on continuum damage mechanics and fracture mechanics. The conception of equivalent stiffness is used in this paper to simulate structural damage severity. Using this approach

an analytical model

which includes three damage parameters（damage location

damage severity

and length of damage）

is developed for cantilever beams. Solutions for the displacement along the cantilever beams under dead load

for both undamaged state and damaged state

are obtained by solving the equations which are deduced from the theories of plane bending and approximately differential equation of flexural. The change rules of displacement for damaged cantilever beams are summarized from comparing the numerical values. The purpose of this paper is to lay groundwork for future studies about structural health monitoring and damage identification.