Packaging materials, such as cardboard, must endure vigorous loads during handling and transport, which could lead to damage to the packaged goods. To ensure that the transported goods reach the consumer safely, a profound knowledge of the behavior of packaging materials under impact loads is required. This study experimentally investigated the behavior of two different cardboard materials under impact loads. Different kinetic energy levels were obtained using a specially developed test rig. First, the resulting damage of the specimens was qualitatively characterized based on digital analysis. Second, the damage was quantitatively analyzed using the imprint diameter after impact as the characteristic parameter. It was found that three different damage phenomena occurred on both investigated materials: imprint, cracking, and breakthrough. Different imprint diameters were detected with increasing kinetic energy of the impactor. The impact load resistance of the material with the higher grammage was higher than that of the material with the lower grammage.

Embossing is an important design and functionality element. For instance, embossing is used to apply braille letters on medical products, or to enhance folding packages or brochures due to haptic effects. Usually, a multilayered cardboard material is used for such types of products. Up to now, high-quality and functional embossing has so far been associated with an extraordinarily large amount of experience-based know-how and with many cost-intense trial-and-error experiments due to the mechanical complexity of cardboard material. In the presented work it is shown how experimental investigations and numerical simulations based on Finite-Element-Analysis can contribute to a virtual prediction of the embossing process and, therefore, can help to reduce time-consuming and expensive experiments.

During the embossing process, a fiber sandwich is compressed between embossing tools. The use of ultrasound causes a short-term increase in the material temperature in addition to causing plastic deformation. The combination of the material compression and an increase in material temperature leads to structural changes, which can be observed by the change in mechanical properties of the cardboard. This work investigated the influence of an ultrasonically induced temperature increase on the structural changes of cardboard. Using three-parameter combinations, different temperature levels were achieved with a material densification of less than 5%. Subsequently, the samples were subjected to selected physical and visual analyses to characterize the change in the fiber structure. With the increase of 124 ºC material temperature there was a decrease of about 15% in the splitting resistance and 10% in the bending stiffness.