Kinematic Methods for the Rational Design of Mechanical Metamaterials

Most materials around us have properties that are determined at extremely small scales. Often the atoms and molecules that make up these materials determine how they behave under load. While this already leads to a great variety of material properties, a lot more is possible. <br/>Mechanical metamaterials use structure to extend the available...

Auxetic interval determination and experimental validation for a three-dimensional periodic framework

Auxetic behavior refers to lateral widening upon stretching or, in reverse, lateral shrinking upon compression. When an initially auxetic structure is actuated by compression or extension, it will not necessarily remain auxetic for larger deformations. In this paper, we investigate the auxetic range in the deformation of a periodic framework...

Efficacy assessment of newly-designed filtering facemasks during the sars-cov-2 pandemic

The SARS-CoV-2 pandemic resulted in shortages of production and test capacity of FFP2-respirators. Such facemasks are required to be worn by healthcare professionals when performing aerosol-generating procedures on COVID-19 patients. In response to the high demand and short supply, we designed three models of facemasks that are suitable for...

Spatial pseudo-rigid body model for the analysis of a tubular mechanical metamaterial

In this paper, a pseudo-rigid body model is proposed for the analysis of a spatial mechanical metamaterial and its application is demonstrated. Using this model, the post-buckling behavior of the mechanical metamaterial can be determined without the need to consider the whole elastic structure, e.g., using finite-element procedures. This is done...

A Rapidly Deployable Test Suite for Respiratory Protective Devices in the COVID-19 Pandemic

Introduction: The current COVID-19 pandemic has caused large shortages in personal protective equipment, leading to hospitals buying their supplies from alternative suppliers or even reusing single-use items. Equipment from these alternative sources first needs to be tested to ensure that they properly protect the clinicians that depend on...

A general method for the creation of dilational surfaces

Dilational structures can change in size without changing their shape. Current dilational designs are only suitable for specific shapes or curvatures and often require parts of the structure to move perpendicular to the dilational surface, thereby occupying part of the enclosed volume. Here, we present a general method for creating dilational...

Assessing Traffic Safety of Dutch Weaving Sections: Validation of the Surrogate Safety Assessment Model combined with VISSIM

Dutch road designers and safety experts are searching for more quantitative methods to evaluate the safety of a (proposed) weaving section than the traditional methods of expert judgement and use of accident records. An alternative would be to determine safety using VISSIM micro-simulation models in combination with the Surrogate Safety...

Dilational triangulated shells using pantographs

Dilational structures are one degree of freedom structures able to change their size without changing their global shape. In this paper, we present a method to create dilational shells with arbitrary curvature. For this, we designed triangular tiles, which can be placed on a triangulation of the desired surface. We present the method and...

Assessing traffic safety of Dutch weaving sections: Validation of the Surrogate Safety Assessment Model combined with VISSIM

Nederlandse wegontwerpers en veiligheidsexperts zoeken naar meer kwantitatieve methodes om de veiligheid van een (voorgenomen) weefvak te bepalen dan de traditionele methodes die gebruik maken van expert judgement en ongevalsregistraties. Een alternatieve methode is om de veiligheid te bepalen met behulp van VISSIM micro-simulatiemodellen in...

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