Experimental and numerical investigations of the mechanical behavior of half sandwich laminate in the context of blanking

Abstract

In this study, the complex mechanical behavior of an aluminum/low-density polyethylene (LDPE) half sandwich structure was investigated during the blanking process. Mechanical tests were conducted for the polymer and metal layer and the delamination behavior of the adhesive between the two layers. A new testing device was designed for detecting the delamination under tensile mode. Corresponding finite element models were established for the mechanical tests of the metal layer and the delamination of both layers for inverse parameter identification. Material parameters for Lemaitre-type damage, Drucker-Prager, and cohesive zone models were identified for the metal, polymer, and adhesive, respectively. A finite-element (FE) model was established for the blanking process of the sandwich structures. The experimental force-displacement curves, obtained in the blanking process of the half sandwich sheet, were compared with the predicted results of the FE model. The results showed that the predicted force-displacement curves and the experimental results were in good agreement. Additionally, the correlation between cutting clearance and changes in the force-displacement curves was obtained. Three feature values quantitatively described the imperfection of the experimental cutting edge. The effect of punch clearance on these values was studied numerically and experimentally. The results indicated that a smaller clearance generated a better cutting-edge quality. The stress state of the half sandwich structure during blanking was analyzed using the established FE model.

Keywords

Sandwich plates / Blanking / Continuum damage mechanics (CDM) / Drucker-Prager model / Cohesive zone model

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