Polymer composites based on natural fillers are currently attracting great attention as alternative materials to glass or synthetic fibre reinforced plastics in several applications, mostly for automotive, appliance and packaging products. The main advantage of employing natural fibres is that these are biodegradable and renewable, and exhibit low cost, low density and high toughness. However t...

Additive manufacturing technologies offer new ways to fabricate cellular materials with composite cell walls, mimicking the structure and mechanical properties of woods. However, materials limitations and a lack of design tools have confined the usefulness of 3D printed cellular materials. We develop new carbon fiber reinforced, epoxy inks for 3D printing which result in printed materials with ...

An irregular lattice model is proposed for simulating quasistatic fracture in softening materials. Lattice elements are defined on the edges of a Delaunay tessellation of the medium. The dual sVoronoid tessellation is used to scale the elemental stiffness terms in a manner that renders the lattice elastically homogeneous. This property enables the accurate modeling of heterogeneity, as demonstr...

Additive manufacturing (or 3D printing) opens the possibility of creating new designs and manufacturing objects with new materials rapidly and economically. Particularly for use with polymers and polymer composites, simple printers can make high quality products, and these can be produced easily in offices, schools and in workshops and laboratories. This technology has opened a route for many t...

To investigate the effect of prepolymerization warming on composites' mechanical properties, three composites were evaluated: Clearfil Majesty (CM) (Kuraray), Z-100 (3M/ESPE), and Light-Core (LC) (Bisco). Specimens were prepared from each composite at room temperature as control and 2 higher temperatures (37°C and 54°C) to test surface hardness (SH), compressive strength (CS), and diametral ten...

The purpose of this study was to evaluate the effect of thermal cycling on the surface texture of restorative materials. Disk-shaped specimens made of seven resin composites (Beautifil: BF; Esthet-X: EX; Filtek Supreme: FS; Inten-S: IS; Point 4: PT; Solare: SR; and Venus: VS) were finished with 1-microm alumina suspension, and then thermocycled between 4 and 60 degrees C in distilled water for ...

We apply terahertz (THz) time-domain spectroscopy for monitoring the curing process of three different light-curing dental composites. Exact knowledge of the sample thickness is required for a precise determination of the THz dielectric parameters, as the materials exhibit shrinkage when they are cured. We find very small but significant changes of the THz refractive index and absorption coeffi...

Composite structures are already in use in secondary parts of the Douglas MD-11 and are planned to be used in the new MD-12X. Plans also exist for their use in primary and secondary structures on the Boeing 777. Douglas’ proposed MD-XX may also incorporate composite materials into primary structures such as the wings and tail. Use of composites in these structures offers weight savings, corrosi...

Major goals for the future of transportation materials include reduced weight of components, reduced cost of materials and increased use of renewable content. Reinforcement of transportation composites with plant fibers has the potential to decrease component weight relative to glass fiber reinforcement, reduce cost of materials relative to carbon fiber reinforcement, and significantly increase...

Additive manufacturing technologies offer new ways to fabricate cellular materials with composite cell walls, mimicking the structure and mechanical properties of woods. However, materials limitations and a lack of design tools have confined the usefulness of 3D printed cellular materials. We develop new carbon fiber reinforced, epoxy inks for 3D printing which result in printed materials with ...