Abstract: Theequivalentstressesofhemisphericalshock-wavestrapstructurewerecalculatedbythe finiteelementprogramLS-DYNAfordifferentconstraintformsandcomparedwiththeexperimental results.Theresultsshowthatthestressconcentrationhappensontheshellneartheentranceandexhaustportandthelocalstressesarefarhigherthanthose fotherparts.Inadditiontothesiteof stressconcentration,themaximumstressisatthethree-fourthoftheheightforthescalespherical shellmodel.Theoverallstressleveldecreasessignificantlyforthesphericalshellwiththefreebottom. Usingthefreebasetoplacethesphericalshellcanfurtherenhanceitscapacityagainstspherical implosion.Contrastingwiththeexperiments,themaximumstresslocationisinlinewiththenumericalresultsafterreinforcingpartsofstressconcentration. Byusingthefreebasetoplacethespherical shellonthegroundinthedesign,itcannotonlyimprovetheanti-explosioncapacityofspherical shells,butalsosavethefoundationtreatment,substantiallyreducesthecostofhemisphericalshock wavestrapstructures.