In　this　paper,　the　nonlinear　vibration　of　a　Mindlin　plate　with　a　side　crack　is　investigated　considering　an　in-plane　preload.　Special　corner　functions　are　incorporated　into　the　admissible　functions　of　displacements　to　describe　the　singularity　in　stress　at　the　crack　tip　as　well　the　discontinuities　in　displacements　and　rotations　across　the　crack.　Based　on　the　Mindlin　plate　theory　and　von　Karman＇s　nonlinear　plate　theory,　the　potential　and　kinetic　energies　of　the　cracked　loaded　plated　are　constructed.　The　Ritz　method　with　the　special　admissible　functions　is　employed　to　determine　the　initial　in-plane　stress　resultants.　The　natural　frequencies　and　modes　of　the　plate　with　or　without　in-plane　preload　are　also　determined　through　the　Ritz　method.　The　nonlinear　dynamical　equations　of　the　plate　are　derived　using　the　Hamilton＇s　principle,　and　are　discretized　into　second-order　ordinary　differential　equations　through　the　Galerkin＇s　method　with　the　three　lowest　order　modes　obtained　by　the　Ritz　method　in　free　vibration.　These　equations　are　transformed　into　of　first-order　ordinary　differential　equations　and　are　solved　via　the　Runge-Kutta　algorithm.　The　nonlinear　dynamical　response　of　the　plate　with　various　parameters　of　crack　and　in-plane　preload　under　transverse　harmonic　excitation　is　presented　through　time　history　of　responses,　phase　portraits　and　bifurcation　diagrams　in　conjunction　with　the　maximum　Lyapunov　exponent.　It　is　demonstrated　that　the　nonlinear　dynamics　of　the　plate　is　complicated　due　to　the　crack　and　in-plane　compressive　preload.　(c)　2020　Elsevier　Ltd.　All　rights　reserved.