A combined experimental-numerical investigation of the failure mode of thin metal foils

Abstract

A combined experimental and numerical analysis of the mechanical response of the thin aluminum foils employed in beverage packaging has been performed using 3D digital image correlation and non-linear finite element techniques. The present contribution focuses on the significant amount of out-of-plane displacements that develop in tensile tests as fracture propagates across the investigated specimens. The influence of this phenomenon on the actual failure mode of the considered metal samples is further discussed

Failure analysis of thin metal foils

“…1. They return the envelope of the uniaxial stress-strain curves obtained from plain material samples [7], and are consistent with those employed in former studies [3,8,15].…”

“…Determining the actual material properties and fracture characteristics of thin foils may be rather problematic since the samples are difficult to handle and sensitive to local imperfections, size and geometric effects. In these conditions, even the interpretation of the output of uniaxial tensile tests may be difficult [7,8]. Alternative loading procedures [9] and full-field displacement monitoring combined with the simulation of the experiment [10,11] have been suggested to overcome some limitations of the most commonly employed parameter calibration procedures.…”

Numerical simulation of non-standard tensile tests of thin metal foils

“…Results show that the wrinkles observed in the real experiments are the likely consequence of compression stresses acting orthogonally to the loading direction [13]. In fact, geometric instability can arise despite the small amplitude of these stresses due to the extremely low bending stiffness of the thin metal foils.…”

“…The main features of the experimental setup and the most significant output of the tests are described in [13][14][15]. The experiments have been simulated by a widely used finite element commercial code that implements both material and geometrical non-linearity [16].…”

“…On the other side, wrinkling phenomena are frequently observed in wide samples and affect the interpretation of the experimental output [10][11][12][13]. These disturbances can be detected by three-dimensional digital correlation techniques [14,15] and potentially reproduced by finite element analysis.…”