Theory of Elasticity

Suchtechnicaltheorieshavealwaysfurnishedresultsexperimentallyveri ed v vi Preface withgoodapproximationandthenamongthemIhavepresentedthosethatarestill usefultoolsofveri cationintheStructuraldesign. Throughouttheanalysisoftheelasticproblemsmyconstantfocushasbeento achievethemaximumclarityandbecauseofthisIhavesacri cedvariousbright discussions. Ihavedevelopedthetreatmentofthesubjectsinclassicalway,butto thelightofthemodernMathematicaltheoryoftheelasticityandwithmoreaccented relief to the connections with the Thermodynamics. Just for this, to give a clear justi cationofthefundamentalequationoftheThermoelasticityIhaveapplieda techniqueofanalysisproperoftheFluiddynamics. Howeverinthediscussionof theunilateralproblems,wheretheFunctionalanalysisiscompulsory,Ihaverelated indetailsthemathematicalaspectsofthetheoreticalanalysis. Roma,Italy AldoMaceri October2009 Contents 1 The Three-Dimensional Problem. . . . . . . . . . . . . . . . . . . . 1 1. 1 AnalysisofStrain. . . . . . . . . . . . . . . . . . . . . . . . . . 1 1. 1. 1 ComponentsofDisplacement. . . . . . . . . . . . . . . . 1 1. 1. 2 In nitesimalDeformation. . . . . . . . . . . . . . . . . . 2 1. 1. 3 ElongationandShearingStrain . . . . . . . . . . . . . . . 4 1. 1. 4 SmallDeformations. . . . . . . . . . . . . . . . . . . . . 5 1. 1. 5 ComponentsofStrain . . . . . . . . . . . . . . . . . . . . 9 1. 1. 6 PrincipalDirectionofStrain . . . . . . . . . . . . . . . . 14 1. 1. 7 InvariantsofStrain . . . . . . . . . . . . . . . . . . . . . 21 1. 1. 8 PlaneStateofStrain. . . . . . . . . . . . . . . . . . . . . 23 1. 1. 9 EquationsofCompatibility. . . . . . . . . . . . . . . . . 24 1. 1. 10MeasurementofStrain . . . . . . . . . . . . . . . . . . . 25 1. 2 AnalysisofStress. . . . . . . . . . . . . . . . . . . . . . . . . . 27 1. 2. 1 StressVector. . . . . . . . . . . . . . . . . . . . . . . . . 27 1. 2. 2 NormalStress¿ShearingStress . . . . . . . . . . . . . . 29 1. 2. 3 ComponentsofStress . . . . . . . . . . . . . . . . . .