Advancing multi-material packaging in the food and beverage industries: A comprehensive investigation of creasing through computational and experimental approaches

The inherent anisotropy, coupled with the material's complex behaviour under different stress directions, packaging material has sparked considerable academic and industrial interest. It has been established that paperboard material can exhibit a stiffness in the machine direction that is up to 100% greater than that in the cross direction and 50% that at 45° direction. The historical perspective on the material's in-plane properties, predominantly assessed through tensile strength testing, has laid the groundwork for contemporary modelling and simulation efforts. Creasing & Bending process are two crucial steps in the packaging industries which are investigated earlier mainly for the paperboard only. In present work the mechanical properties of the paperboard along with the paperboard with barrier layers were investigated to understand the effect of barrier layers on the packaging materials. Tensile testing was performed to understand the anisotropy of paperboard along with the paperboard with barrier layers which provides significant difference in the properties of the paperboards with barrier layers resulting in determination of important characteristics including tensile strength and Young's modulus were obtained through tensile testing, which was used to evaluate their mechanical qualities. The performance of the materials in load-bearing applications can be evaluated using these testing data. A crucial stage in packaging production, creasing is also investigated in the work to look at how the material reacts when folded and the force required for creasing at different depth for paperboard and paperboard with barrier layer. The creasing parameters, which include the different depth and constant width of the creases, were thoroughly examined. Visual analysis of the microstructure of creased samples was performed using scanning electron microscopy (SEM), which revealed initial delamination in the creased zone and possible damage that may have occurred during creasing. Bending tests were also used to study the bending process, which is crucial in the package manufacturing process. The results of these tests revealed how the material responded to bending and how well its response to the bending force applied to it till 90 without rupturing. Bending process were used to determine the bending moment of the paperboard and paperboard with barrier layer, creased at different depths with respect to the angle. Bending process was also found to be the major source for the delamination of paperboard layer while maintain the outer and innermost layers. The bending process affects the internal structure and potential faults within the material. To gain a deeper understanding of this, SEM and X-Ray Computerised tomography (XCT) pictures were taken. Surface and subsurface features were analysed using SEM imaging, and voids, delamination’s, and the integrity of barrier layers could be seen with XCT, providing 3D insights into the underlying structure. The required input data for the numerical model was determined in a series of experiments explained. Consequently, the numerical model using LS-DYNATM allows to analyse the tensile, creasing and bending process for the paperboard and paperboard with barrier layers. A thorough comprehension of the materials' behavior under various conditions can be achieved by the integration of experimental testing, state-of-the-art imaging methods, and numerical simulations. The mechanical behavior of paperboard and paperboard with barrier layers is extensively studied in this work, particularly during tensile loading, creasing, and bending. By incorporating simulation studies, our understanding of material reactions is enhanced, and manufacturing process optimization is made easier. With possible uses in sectors necessitating strong paper-based packaging solutions, these results add to the development of packaging material design and production.