With their increased energy absorption capacity, auxetic materials are perfectly fit to develop new, enhanced lightweight crash absorbers for cars. Herein, the mass distribution along the struts is optimized via finite element analysis with a parameterized optimization. Four different auxetic unit cells are taken from the literature and their struts parameterize, the models simulate, and the mass specific energy absorption capacity optimizes. The two models with the highest energy absorption capacity are then selected for experimental investigation and produced by additive manufacturing from a polymer. To further enhance the mechanical properties, the specimens are electrochemically coated with nickel and the polymer molten out by pyrolysis. Those Ni/polymer hybrids are subjected to quasistatic and dynamic impact experiments. Only a small strain rate sensitivity can be detected under dynamic loading, namely, a higher plastic collapse and higher plateau stress. The hollow struts are folding instead of bending, which render them much weaker than predicted by the simulation. In conclusion, it is possible to improve existing crash absorber elements with tailored auxetic hybrid structures. They absorb higher amounts of energy without changing their stiffness under dynamic loading while saving mass and cost.

The increasing demands of safety, cost reduction or weight reduction on components calls for new, multifunctional materials. Mechanical metamaterials, such as auxetic materials, provide enhanced properties due to a specially tailored microstructure. The negative Poisson’s ratio of auxetics for instance increases the impact and thermal shock resistance. In the present contribution a parametrized model of a modified auxetic structure was simulated using the finite element software ABAQUS^®. Three out of five geometry parameters were varied between a minimum and maximum value to establish their impact on the energy absorption capacity and the Poisson’s ratio using design of experiment (DoE). All eight resulting structures were additively manufactured by selective laser melting (SLM) and experimentally investigated under uniaxial compression to validate the simulations. The size of a unit cell has the biggest impact on both target values. Energy absorption capacity and Poisson’s ratio are directly competing in the optimization, hence a compromise is necessary. The quasi-static compression experiments verified the simulation results up to the first collapse. Afterwards, the specimens failed brittle, which was not accounted for in the simulations and may result from the high process complexity of SLM manufacturing.

Flexible endoscopic evaluation of swallowing (FEES) is one of the most important methods for instrumental swallowing evaluation. The most challenging part of the examination consists in the interpretation of the various observations encountered during endoscopy and in the deduction of clinical consequences. This review proposes the framework for an integrated FEES-report that systematically moves from salient findings of FEES to more advanced domains such as dysphagia severity, phenotypes of swallowing impairment and pathomechanisms. Validated scales and scores are used to enhance the diagnostic yield. In the concluding part of the report, FEES-findings are put into the perspective of the clinical context. The potential etiology of dysphagia and conceivable differential diagnoses are considered, further diagnostic steps are proposed, treatment options are evaluated, and a timeframe for re-assessment is suggested. This framework is designed to be adaptable and open to continuous evolution. Additional items, such as novel FEES protocols, pathophysiological observations, advancements in disease-related knowledge, and new treatment options, can be easily incorporated. Moreover, there is potential for customizing this approach to report on FEES in structural dysphagia.