Effect of Material and Geometry Variations on Beam under Patch Loading

This work was initiated to study the influence of geometry and material variations on the structural response of an aluminium I-beam subjected to concentrated loading. The beam behaviour was computed with a previously validated LS-DYNA model, and an analytical response surface expression for the maximum load capacity was established. The deviation between the response surface estimate and the numerical analysis result was within 1.1 %, and less than 0.35 % in the most interesting parameter range. The probability distributions of all the material parameters, the thicknesses and the geometrical imperfections were established on measurements from former works, and the code PROBAN was used to evaluate the influence of variability in the model parameters. It was found practical to separate two different cases: one reflecting the variation occurring in a certain extrusion, and the other indicating the scatter in a random batch. The first case was shown to give 20 % higher design capacity indicating that it may be attractive to improve the control of the production process.