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The potential of paper and paperboard as fiber-based materials capable of replacing conventional polymer-based materials has been widely investigated and evaluated. Due to paper’s limited extensibility and inherent heterogeneity, local structural variations lead to unpredictable local mechanical behavior and instability during processing, such as mechanical forming. To gain a deeper understanding of the impact of mechanical behavior and heterogeneity on the paper forming process, the Finite Element Method (FEM) coupled with continuum modeling is being explored as a potential approach to enhance comprehension. To achieve this goal, utilizing experimentally derived material parameters alongside stochastic finite element methods allows for more precise modeling of material behavior, considering the local material properties. This work first introduces the approach of modeling heterogeneity or local material structure within continuum models, such as the Stochastic Finite Element Method (SFEM). A fundamental challenge lies in accurately measuring these local material properties. Experimental investigations are being conducted to numerically simulate mechanical behavior. An overview is provided of experimental methods for material characterization, as found in literature, with a specific focus on measuring local mechanical material structure. By doing so, it enables the characterization of the global material structure and mechanical behavior of paper and paperboard.

Abstract The process design of flat die rolling operations can be a tedious and costly process due to the challenges posed by small process windows. Within this work, an effort is made to closely investigate and understand the process limits caused by excessive slippage of the workpiece. Optical measurements are carried out to capture the characteristics of excessive slippage and the influence of the stroke rate and the tribological system on this process limit. Large differences in slippage were observed, depending on the tribological system. While systems with polymer based lubricants showed excessive slippage at low stroke rates, systems using oil or no lubricant endured higher stroke rates before process limits were reached. The optical measurements revealed three major forms of slippage: successful rolling without slippage, failure due to excessive slippage at process start, and failure due to excessive slippage at around one workpiece rotation.

In dentistry, the most commonly used implant materials are CP-Titanium Grade 4 and Ti-6Al-4V ELI, possessing comparably high Young’s modulus (>100 GPa). In the present study, the second-generation titanium alloy Ti-13Nb-13Zr is investigated with respect to the production of advanced dental implant systems. This should be achieved by the fabrication of long semi-finished bars with high strength and sufficient ductility to allow the automated production of small implants at low Young’s modulus (

A novel process design for the damage-free and highly accurate positional integration of an optical multi-axial force sensor into a hollow tube by means of rotary swaging is introduced. Numerical simulations reveal the relevant process phenomena of thin disc joining inside a pre-toothed hollow tube and help us to find an optimal process design. Experimental trials show the significant effect of the axial material flow and the number of tools on the rotary swaging process. By taking these effects into account, successful form- and force-fit joining of the sensor carrying discs into the tube can be achieved. Successful joining of an optical sensor for bending force and torque measurement shows hysteresis-free sensory behavior and thus backlash-free joining of the sensor carrier discs. The paper concludes with a presentation of the results of a numerical study on a potential closed-loop approach to the joining process.