Material characteristics of 3D printed concrete subjected to highly dynamic loading

In this study the quasi-static, low- and high-dynamic compressive properties, and ballistic resistance of two types of 3D printed concrete have been investigated and compared to normal strength cast concrete (NSC). For the printed materials, an unreinforced commercially available mortar and a PVA fiber-reinforced strain-hardening cementitious...

Quality model for recycled plastics (QMRP): An indicator for holistic and consistent quality assessment of recycled plastics using product functionality and material properties

One of the key challenges for plastics in a circular economy is its degradation during use, washing and reprocessing. The reduced quality of recycled plastic waste leads to its use in inferior applications. This study presents a novel quality model which incorporates degradation, degree of mixing and contaminations. The model estimates a single...

Use of HSS and VHSS in steel structures in civil and offshore engineering: Requirements regarding material properties

In Memoriam of Prof. Dr. Bernt Johansson. The use of high-strength steels (HSS, 460 < fy ≤ 700 MPa) and particularly very high-strength steels (VHSS, fy > 700 MPa) is limited in steel structures in civil and offshore engineering. This is due to a lack of experience in structures made of these materials and a lack of understanding of the...

Thiol-Ene Alginate Hydrogels as Versatile Bioinks for Bioprinting

High Piezoelectric Voltage Coefficient in Structured Lead-Free (K,Na,Li)NbO3 Particulate—Epoxy Composites

A high-voltage coefficient has been found in lead-free piezoelectric particulate composites based on epoxy with lead-free (K0.50Na0.50)0.94Li0.06NbO3 (KNLN) piezoceramic particles with a natural cubic morphology. The KNLN powder used in the composites has been prepared using a new solid-state double calcination processing route. These particles...

Enhancing energy harvesting potential of (K,Na,Li)NbO3-epoxy composites via Li substitution

In this study, the influence of Li substitution on the piezoelectric performance of lead-free K0.5Na0.5NbO3 (KNN)-epoxy composites is explored. KNN piezoceramic particles modified with 0-12 mol% of Li are prepared via a double calcination technique, resulting in a perovskite particulate which transitions from an orthorhombic to tetragonal...

Dynamic material characterization by combining ballistic testing and an engineering model

At TNO several energy-based engineering models have been created for various failure mechanism occurring in ballistic testing of materials, like ductile hole growth, denting, plugging, etc. Such models are also under development for ceramic and fiberbased materials (fabrics). As the models are energy-based they can be directly compared to...

Poly(dendrimers) with phosphorescent iridium(III) complex-based side chains prepared via ring-opening metathesis polymerization

Phosphorescent poly(dendrimers) with a norbornene-derived backbone have been synthesized using ring-opening metathesis polymerization with the Grubbs III catalyst. The dendrimers are comprised of a heteroleptic iridium(III) complex core with two 2-phenylpyridyl ligands and a phenyltriazolyl ligand, biphenyl-based dendrons, and 2-ethylhexyloxy...

Tensile properties of explosively formed 316L(N)-IG stainless steel with and without an electron beam weld

The mechanical properties of two explosively formed saddle shaped 60 mm thick plates of 316L(N)-IG steel with and without an electron beam weld have been investigated. Two different conditions have been characterized: (1) Reference condition and (2) ITER relevant condition. The reference material exhibits consistent results for both plates,...

Efficient extraction of thin-film thermal parameters from numerical models via parametric model order reduction

In this paper we present a novel highly efficient approach to determine material properties from measurement results. We apply our method to thermal properties of thin-film multilayers with three different materials, amorphous silicon, silicon nitride and silicon oxide. The individual material properties are identified by solving an optimization...

Materials as inherent ignition sources for dust explosions during spray drying

During spray drying where a solution is dispersed in small droplets through a nozzle the liquid evaporates by means of hot air. In a large number of these processes organic materials are processed so three out of four factors for dust explosions to occur are already present. The only thing missing for a dust explosion to occur is an ignition...

Stress-strain curves of steel and aluminium exposed to natural fires

The temperature-dependent reduction factors on the yield stress in codes for steel structures, ky, are derived using a constant heating rate and a constant stress, where the influence of creep is implicitly taken into account. This paper considers the material properties of steel and aluminium on the basis of a Natural Fire Safety Concept, where...

Lifetime of piezoceramic multilayer actuators: Interplay of material properties and actuator design

We report an investigation into factors limiting the functional lifetime of multilayer piezoceramic actuators. The study consists of a combination of lifetime experiments by means of an accelerated lifetime test, inspection of the actuator microstructure at different stages of the accelerated lifetime test, and numerical simulation of the...

Moisture flow by micro structural contraction

Material properties of building and construction elements are requested to last for an increasingly longer service life. For cementitious materials in particular, the "birth" of these properties emerge at the early stage of the hardening process. It is the development of the microstructure that determines the load bearing capacity as well as the...

Crash behavior of columns in relation to material properties and joining techniques

Ths strain rate behavior of mild-steel and high strength steel qualities has been investigated. The hardening as a function of the strain rate of a set of steel qualities was determined, and it was found that the gain in strength for high-strength steels is not in proportion to the static yield-strength. The absolute increase in strength for...

Structural lightweight concrete: recent research

As a result of a number of reasons new interest developed into the use of lightweight aggregate concrete. Within the scope of this development, a modemized code for lightweight concrete had to be written. In order to support this development, a number of research projects have been carried out. The aim of the research was to verify the...