Theproblemsonthenon-uniquenessandstabilityofatwo-familyfiberreinforcedanisotropicincompressiblehyper-elasticsquaresheetunderequibiaxialtensiledeadloadingareexaminedwithintheframeworkoffiniteelasticity.Foratwo-familyfiber-reinforcedsquaresheet,whichisin-planesymmetricandsubjectedtothein-planesymmetrictensionindeadloadingontheedges,threesymmetricallydeformedconfigurationsandsixasymmetricallydeformedconfigurationsarepossibleforanyvaluesoftheloading.Moreover,anotherfourbifurcatedasymmetricallydeformedconfigurationsarepossiblefortheloadingbeyondacertaincriticalvalue.Thestabilityofallthesolutionsisdiscussedincomparisonwiththeenergyofthesheet.Itisshownthatonlyoneofthesymmetricsolutionsisstablewhentheloadingislessthanthecriticalvalue.However,thissymmetricsolutionwillbecomeunstablewhentheloadingislargerthanthecriticalvalue,whileoneofthefourbifurcatedasymmetricsolutionswillbestable.
