简介：ThesymmetricGalerkinboundaryelementmethod(SGBEM)insteadofthefiniteelementmethodisusedtoperformlowerboundlimitandshakedownanalysisofstructures.Theself-equilibriumstressfieldsareconstructedbyalinearcombinationofseveralbasicself-equilibriumstressfieldswithparameterstobedetermined.Thesebasicself-equilibriumstressfieldsareexpressedaselasticresponsesofthebodytoimposedpermanentstrainsandobtainedthroughelastic-plasticincrementalanalysis.Thecomplexmethodisusedtosolvenonlinearprogramminganddeterminethemaximalloadamplifier.Thelimitanalysisistreatedasaspecialcaseofshakedownanalysisinwhichonlytheproportionalloadingisconsidered.ThenumericalresultsshowthatSGBEMiseffcientandaccurateforsolvinglimitandshakedownanalysisproblems.