主题词:Engineering Mechanics,mechanics of materials,Strength of Materials,linear elasticity,Plane stress state,Engineering Mechanics: Bars and Bar Systems,Beams,Beam deflections,Shear stresses in beams,Torsion in beams and bars,Energy Methods in Engineering Mechanics,The principle of virtual forces,Reciprocity theorems,Buckling of bars and Euler cases,The Euler-Bernoulli beam