BARRELLING AND BUCKLING INSTABILITIES OF ELASTIC RODS

The problem of nonuniqueness of equilibrium states of an elastic bar under axial load is studied within the direct nonlinear theory of elastic rods. The linearization of the problem about the straight compressed trivial state determines two different sets of critical loads depending on the material response. The existence of bifurcating branches from the trivial state is proved for the first critical load of each set.