Cork–PLA composite filaments for fused deposition modelling

Low-velocity impact behaviour of a shear thickening fluid (STF) and STF-filled sandwich composite panels

The foam material of interest in this investigation is a rigid closed-cell polyurethane foam PMDI with a nominal density of 20 pcf (320 kg/m{sup 3}). Three separate types of compression experiments were conducted on foam specimens. The heterogeneous deformation of foam specimens and strain concentration at the foam-steel interface were obtained using the 3-dimensional digital image correlation (3D-DIC) technique. These experiments demonstrated that the 3D-DIC technique is able to obtain accurate and full-field large deformation of foam specimens, including strain concentrations. The experiments also showed the effects of loading configurations on deformation and strain concentration in foam specimens. These DIC results provided experimental data to validate the previously developed viscoplastic foam model (VFM). In the first experiment, cubic foam specimens were compressed uniaxially up to 60%. The full-field surface displacement and strain distributions obtained using the 3D-DIC technique provided detailed information about the inhomogeneous deformation over the area of interest during compression. In the second experiment, compression tests were conducted for cubic foam specimens with a steel cylinder inclusion, which imitate the deformation of foam components in a package under crush conditions. The strain concentration at the interface between the steel cylinder and the foam specimen was studied in detail.more » In the third experiment, the foam specimens were loaded by a steel cylinder passing through the center of the specimens rather than from its end surface, which created a loading condition of the foam components similar to a package that has been dropped. To study the effects of confinement, the strain concentration and displacement distribution over the defined sections were compared for cases with and without a confinement fixture.« less

Full-field characterization of mechanical behavior of polyurethane foams.

Experimental and numerical investigation of static and fatigue behaviors of composites honeycomb sandwich structure

A review of the crashworthiness performance of energy absorbing composite structure within the context of materials, manufacturing and maintenance for sustainability

This study investigates the use of expanded cork (a 100% natural lightweight agglomerate material) as a core material in composite sandwich structures with carbon fiber face sheets. The characterization performed focused particularly on energy absorption capability. Rohacell® 110 IG, a synthetic foam commonly used as a core material in high performance aerospace applications, was also used and characterized to compare the energy absorbing characteristics of the sandwich composites. Bending tests were done to examine the stiffness of the sandwich beams. Wavenumber and damping tests were performed to characterize the acoustic and vibrational damping properties of the composites. Both full penetration and partial penetration low velocity impact tests were completed to determine the damage resistance of the composites. It was seen that when compared to the synthetic foam, expanded cork showed a decrease in bending stiffness, but a large improvement in acoustic, damping, and impact damage resistance characteristics. It seems that expanded cork could be an attractive lightweight sandwich core material that will allow for increased energy absorption and will also reduce the carbon footprint of the structures.

Joe Walsh

Papers

Low velocity impact resistance and energy absorption of environmentally friendly expanded cork core-carbon fiber sandwich composites

Experimental characterization of temperature dependent dynamic properties of glass fiber reinforced polyurethane foams