Underwater　explosion　tests　were　performed　beneath　the　clamped　square　plates　using　2.5　g　TNT,　RDX,　and　B　explosive.　The　dynamic　responses　of　the　plate　were　investigated　under　the　joint　actions　of　underwater　explosive　shock　wave,　bubble　pulsation,　and　water　jet　load.　The　results　show　that:　lower　energy　TNT　causes　permanent　convex　deformation　integrally　on　the　square　plate,　whereas　higher　energy　explosives　B　and　RDX　cause　permanent　convex　deformations　on　the　middle-upper　side　and　a　concave　deformation　on　the　plate’s　edge.　To　further　investigate　the　damage　characteristics　of　clamped　square　plate　caused　by　different　explosives,　numerical　simulation　was　performed　using　Abaqus.　The　results　show　that:　during　the　process　of　bubble’s　expansion,　its　internal　pressure　gradually　drops　to　a　lower　level　than　the　atmosphere　pressure,　resulting　in　a　pressure　difference　and　concave　deformation　of　the　plate.　The　steel　plate　then　rebounds　as　a　result　of　the　combined　action　of　bubble　pulsation　and　water　jet.　Different　explosives　show　different　bubble　effect　during　the　process　of　plate　rebounding,　which　is　the　primary　reason　for　the　various　damage　forms.　Increasing　the　plate　thickness　effectively　prevents　the　clamped　square　plate’s　middle　convex　side　concave　deformation.　This　work　can　be　employed　to　design　underwater　warheads.　©　2024　Tsinghua　University.　All　rights　reserved.