A　time-domain　boundary　element　method　is　applied　to　simulate　the　matrix　crack　propagation　in　composite　with　inclusions　under　impact　loading.　The　crack-growth　direction　is　determined　by　the　maximum　circumferential　stress　criterion,　and　the　instantaneous　velocity　is　approached　by　a　bisection　technique.　New　crack-tip　elements　of　inconstant　length　are　added　to　the　moving　crack-tip　to　simulate　the　unsteady　growth　at　each　propagation　time　step.　The　interactions　of　a　crack　with　various　clusters　of　inclusions　are　investigated.　©　2011　IEEE.