An elastic-plastic finite element analysis of notched aluminum panels.

Abstract

Finite element, elastic and plastic analyses of various aluminum panels, containing holes and notches, were conducted for comparison with photoelastic experimental results. A FORTRAN IV program, ADINA (Automatic Dynamic Incremental Nonlinear Analysis) , was used for both linear and nonlinear analyses. Mesh refinements were used for each panel and the monotonically convergent results were extrapolated using Richardson's method. Stresses were locally smoothed from the Gauss integration points to the nodal points. Eight noded, isoparametric elements were used throughout. Modification to an ADINA preprocessor program, also coded in FORTRAN IV, was made for use with a VERSATEC plotter. Comparisons were made to the elastic, analytic series solution by Howland for a circular hole in a finite strip. The finite element results varied by less than one percent from Howland 's solution. Handbook values for the elastic stress concentration factors of the geometries investigated differ from finite element results by less than one percent in all cases. The photoelastic works of Frocht were also compared where applicable. Stresses in the plastic range obtained from slip-line theory for a rigid-perfectly-plastic material show excellent correlation to a finite element analysis of such a material. Comparisons to elastic and plastic experimental data were made for the panels analyzed and show good correlation to finite element results.