Until　now,　few　literatures　on　the　active　vibration　control　of　lattice　sandwich　structures　employing　the　piezoelectric　materials　have　been　published.　Motivated　from　this,　the　active　vibration　control　of　sandwich　beams　with　pyramidal　lattice　core　is　investigated　in　this　paper.　The　piezoelectric　materials　are　bonded　on　the　top　and　bottom　surfaces　of　the　beam　to　act　as　the　actuator　and　sensor.　In　the　structural　modeling,　the　discrete　lattice　truss　core　is　converted　to　an　equivalent　homogenized　continuum　material.　Hamilton＇s　principle　with　the　assumed　mode　method　is　used　to　develop　the　dynamical　model　of　the　structural　systems.　By　using　the　standard　eigenvalue　methodology,　the　natural　frequencies　are　obtained.　The　velocity　feedback　control　method　and　a　linear　quadratic　regulator　(LQR)　are　used　to　design　the　controllers　and　actively　suppress　the　vibration　of　the　structural　system.　Frequency　and　time　domain　responses　are　computed　to　analyze　the　control　effects　on　the　sandwich　beam　with　pyramidal　lattice　truss　core.　It　is　observed　from　the　numerical　simulation　that　the　velocity　feedback　control　and　the　LQR　control　methods　both　can　effectively　suppress　the　vibration　of　the　lattice　sandwich　beam.　(C)　2014　Elsevier　Ltd.　All　rights　reserved.