Comparative Analysis and Design of Bridge Pier for various Geometries along height

Slender member is subjected to axial load and biaxial bending moment and fails due to buckling. This buckling is caused due to slenderness effect also known as ‘P∆’ effect. This buckling gives rise to excessive bending moment occurring at a point of maximum deflection. This additional bending moment is considered in second order analysis. The objective of the research reported in this paper is to formulate bending moment equation by using beam column theory and to study the behaviour of solid circular section and hollow circular section of bridge pier. The optimization in area of cross section is done by providing a combination of solid and hollow circular section in place of a solid circular section of pier within permissible limits. A comparative study on behaviour for all three conditions is been carried out. Keywords: slender column, buckling, ‘P∆’ effect, beam-column, second order analysis, bridge pier.

Springback prediction and compensation method for anisotropy sheet in multi-point forming

Multi-point forming (MPF) is widely used for three-dimensional (3D) curved surfaces, and the multi-point die (MPD) is reconstructed with the desired curvature and the compensated curvature which is caused by springback. Springback is affected by mechanical anisotropy of material in MPF. To predict the springback of anisotropy sheet in MPF process, the finite element models were established based on the three different yield criteria namely; von Mises, Hill's 48 and Yld2004-18p. To compensate the springback of anisotropy sheet, an algorithm with consideration of anisotropy for doubly curved sheet was proposed based on the results of the finite element simulation and the elastic perfect plastic biaxial bending model. The direct curvature adjustment (DCA) method and the Non-Uniform Rational B-Splines (NURBS) method are used to generate the die surface after springback compensation. The final shape of the workpiece is obtained by the execution of iterative compensation. The forming experiments were carried out and the results show that the anisotropic model is closer to the experiment than the isotropic model. Finally, the influences of blank thickness, part shape and forming radius on compensation accuracy were discussed to verify the applicability of the algorithm.