Born Aug. 23, 1797, in Villiers-en-Bière, Seine-et-Marne Department; died Jan. 6, 1886, in St-Ouen, Loire-et-Cher Department. French scientist in the field of mechanics. Member of the Académie des Sciences (1868).
After graduating from the Polytechnic School in Paris in 1816, Saint-Venant worked as an engineer. He subsequently taught at the School of Bridges and Roads in Paris and at an agronomy institute in Versailles.
Saint-Venant’s principal works dealt with the theory of elasticity, the strength of materials, hydraulics, and hydrodynamics. Saint-Venant introduced the semi-inverse method of solving problems in the theory of elasticity and formulated the principle of the moderation of boundary conditions (Saint-Venant principle). In 1855 he constructed a general theory for the torsion and bending of prismatic beams. Saint-Venant studied the collision of elastic beams and laid the foundations for the theory of plasticity of a perfectly plastic body. He also studied the flow of gases from apertures and the motion of liquids in open channels.