Abstract:Based on the Mead-Markus assumptions,the assumed mode method(AMM)was used to model a partially ACLD beam.And the validity and effectiveness of AMM were examined by comparing the results with those of FEM.Furthermore,the geometrical effects of a ACLD patfch as ,PZT thickness,VEM thickness,its location and length on matural frequencies and modal loss factors of the beam were also atudied.It seemed that it is useful for damping efffct to increase PZT thickness,reduce VEM thickness and exted the ACLD patch.