Inthiswork,wefocusonassessingthegroupeffectoflocalizedcorrosionontheultimatestrengthofthemarinestructuralplatesandstudytheload-deformationbehaviorsofplatesofvariousslendernessanduniaxialcompression.Meanwhile,weinvestigatedifferentcorrodedpatternsfromasinglecircularpitto25circularpitsdistributedovertheplateandcarryouthundredsofnonlinearfiniteelementsimulationsbycombiningthenumber,depth,distributionofpitswithimperfectionsandslendernessofplate.Thedistributionofmultiplepitscausesscatteringofstressconcentrationontheplate,thentheplasticsectionofplatechangeswithwiderdistributionofdamagesimultaneously.Theultimatestrengthariseswhenun-loadingzonecomprisedoftheyieldingstripsandholesextendsacrosstheplate.Itcanbeconcludedthatthecorrodedconditiondefinedasgroupeffectofpitsmanipulatesthedeformationstateandtheloadingcapacityofplateattheultimatestrengthmodethatcoincideswiththeproportionofeffectiveloadingareaandsectionintheprocessofpost-buckling.Tovalidatetheeffectofpitsgroup,weperformthenumericalexperimentsofthepost-bucklingofsteelplatescontainingpitsinarowwithdifferentorientation.
