Mechanical Characterization of Foils with Compression in Their Planes

Abstract

An experimental-computational procedure is proposed and numerically validated for combined compression and bending tests and for identification of parameters in anisotropic elastic-plastic material models of the mechanical behavior of foils, specifically of paperboards and laminates for liquid containers. From the experimental standpoint, the proposed technique generalizes the instrumentation and “modus operandi” of traditional uni-axial testing with the following novel provisions: the foil specimen is stabilized by two elastic “blocks” of a well known polymeric material (therefore, such system is called “sandwich” herein); “full-field” displacement measurements by a digital image correlation (DIC) technique are envisaged, and examined by sensitivity analyses with respect to the sought parameters; the experimental data provided by DIC might be enriched by the digitalized relationship between external loading and imposed displacements in the test; test simulations (“direct analyses”) are performed by finite element modeling and the sought parameters governing the specimen behavior are assessed by minimization of a discrepancy function (inverse analysis); the minimization by mathematical programming is made fast and economical by radial basis functions (RBF) interpolations based on preliminary proper orthogonal decomposition (POD).

Keywords:

• material parameter identification
• foils subjected to compression and bending
• “sandwich” experimental system
• anisotropic elastic-plastic material
• digital image correlation
• generalized variables