Finite element and experimental investigation on the effect of repetitive shock in corrugated cardboard packaging 821
parameters for shell model that replaces 3D structural corrugated cardboard model is not an easy task. An inverse identification procedure can be used to calibrate effective elastoplastic parameters [7, 19]. The main concern of this study is estimating the effect of repetitive shock on corrugated cardboard boxes. Novelty of this study is the construction of the Damage Boundary Curve (DBC) using a vibration table and a finite element approach with an elastoplastic homogenization model for corrugated cardboard. 2. Material and Methods In this section, we present the corrugated cardboard and the experimental techniques used in this study. To determine the material parameters, we carried out tensile tests on the papers constituting the corrugated cardboard. Corrugated cardboard boxes were then tested to study their behavior in compression and under repetitive shock leading to cumulative fatigue. 2.1 Corrugated Cardboard For this study, we have used a single wall corrugated cardboard material consisting of a fluted corrugated sheet and two flat linerboards (Fig. (1)). The thickness and grammage (weight per meter square) of each constituent are given in Table (1). The corrugated cardboard was immersed in water to separate the sheets. The peeled off sheets were wrung by pressing them between absorbent papers before their conditioning at 23°C and 50% relative humidity (RH) for two days. 2.2 Tensile Tests Using a cutting table (ZÜND M-1600), we cut ten standard specimens from the constituents of the corrugated cardboard to perform tensile tests in three directions (MD, CD and 45°). To ensure a better grip of the clamps when tightening these specimens, we glued pieces of rigid compact cardboard to both ends. The tensile tests were performed on an MTS Adamel-Lhomargy DY35XL testing machine equipped with 2 kN load cell. The standard test to evaluate a paperboard’s tensile properties was conducted on a 10 mm wide specimen that was clamped with a free span of 100 mm. The specimen was deformed at a constant rate of 10 mm/min while the force is recorded. To minimize the influence of climatic conditions, all tests were performed at 23°C and 50% RH. 2.3 Box Compression Test Corrugated cardboard boxes are often stacked on one another to certain layers to form pallets. The box must have the capacity to bear the load during storage and transport. It is thus important to check the compression strength of the box. The box compression strength is a direct measure of its stacking strength. Figure (2) shows the unfolded box with dimensions LxWxH = 300x200x180 mm 3 . The box is compressed at a constant rate of 10 mm/min between two rigid platens. The platens are fixed so that they remain parallel on an INSTRON 4204 testing machine equipped with a 5 kN load cell. The compression tests were carried out under standard conditions at 23°C and 50% RH. 2.4 Repetitive Shock Experiments Corrugated cardboard boxes are used to protect their contents from the hazards encountered in handling, transportation, and storage. These packages are at risk of being dropped or damaged during handling and shipping. Shock is one of the more troublesome of these hazards. Shock testing techniques are used to identify the vulnerabilities of engineered products and components. Controlled shock input by shock machines provides a convenient method for evaluating the ability of shipping containers to withstand shocks.
Fig. 1. Geometry and dimensions of flute B corrugated cardboard.
W
L
H
Fig. 2. Unfolded box.
Table 1. Thickness and grammage of flute B corrugated cardboard. Thickness (mm) Grammage (g/m 2 ) Top linerboard 0.180±0.004 140 Fluting 0.150±0.008 113 Bottom linerboard 0.217±0.004 130
Journal of Applied and Computational Mechanics, Vol. 7, No. 2, (2021), 820-830
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