Dynamic elasto-plastic buckling of initially curved bars (Q1084921)

The longitudinal impact of a slightly curved bar by a heavy rigid hammer with a low velocity is analyzed numerically. The dynamic elasto-plastic buckling behavior is discussed for the bar subjected to the plastic strain of the same order as the elastic. A lumped-parameter model for the solid bar is assumed and governing equations with geometric and material nonlinearity are replaced by finite difference equations. The stress at each point on the cross section is evaluated by taking account of the detailed deformation history of that point. The bending moment is calculated by integrating this stress. This method has been confirmed to give more accurate results than the conventional method for bars buckled dynamically with the high modal deflection and bars of slenderness ratio 30-100, in which the stress distribution over the cross section is highly nonlinear. The experimental results on aluminium bars were in good agreement with the numerical results.