'Instability of doubly curved sheetmetal panels formed with residual stresses'

摘要

A computer software program based on an energy-consistent shell formulation using the DMV shell theory, the total Lagrangian description of motion and a finite difference energy method has been developed for the geometrically nonlinear analysisof thin imperfect shells. Some numerical procedures such as the Newton-Raphson process, the displacement control method and the constant arc length method are used to trace the prebuckling and postbuckling paths of thin shallow shells withresidual (initial) stresses. Such residual stresses are caused by elastic-plastic loading and elastic unloading in a sheet metal forming process.A Galerkin approach has also been used to estimate the global as well as local elastic instability and postbuckling behavior of simply supported shallow shells of rectangular planform with residual stresses and geometrical imperfections.