OBJECTIVES The purpose of this study was to investigate the viscoelastic properties related to the handling characteristics of composites. METHODS A custom-designed vertical oscillation rheometer (VOR) was used for the rheological measurements of composites. The VOR consists of three parts: (1) a measuring unit, (2) a deformation induction unit, and (3) a force-detecting unit. Two medium-visc...

The effects of starch and aging on the mechanical properties of starch/poly(hydroxyester ether) (PHEE) composite materials were characterized. Native or modified cornstarches were extruded with PHEE. Composites were aged for up to 20 months at either 23°C and 50% relative humidity (RH) or over calcium sulfate to keep the composites dry. The tensile strength (TS) of the composites was affected b...

Evolution of microdamage in advanced composites was experimentally studied in this paper. A new method of acoustic emission (AE) analysis of histories of different damage mechanisms was formulated based on a combination of transient AE classification and multiparameter filtering. The capabilities of the method were illustrated on examples of damage evolution in several graphite/epoxy composites...

AlN/epoxy composites with high thermal conductivity were successfully prepared by infiltrating epoxy into AlN porous ceramics which were fabricated by gelcasting of foaming method. The microstructure, mechanical, and thermal properties of the resulting composites were investigated. The compressive strengths of the AlN/epoxy composites were enhanced compared with the pure epoxy. The AlN/epoxy co...

Concrete columns confined with high-strength fiber reinforced polymer (FRP) composites can enhance the strength as well as the ductility of such structures. In recent years, the use of FRP composites to repair and strengthen existing reinforced concrete (RC) structures has been widely used. When the columns of existing RC structures are wrapped with FRP composites, the core concrete of such col...

The creation of highly oriented, co-extruded polypropylene (PP) tapes allows the production of recyclable ‘all-polypropylene’ composites, with a large temperature processing window (O30 8C) and a high volume fraction of highly oriented PP (O90%). These composites show little deviation of mechanical properties with compaction temperature. This paper introduces all-polypropylene composites and re...

The helix geometry model of 3D braided composites has been presented, which truly reflects the braided manner and coincides with the actual configuration of the braided composites. The longitudinal tensile stress-strain relationships and the strength of 3D braided composites under the tension loading have been predicted by a finite multiphase element method (FMEM) based on the helix geometry mo...

In the present work, fabrication and evaluation of low density glass – epoxy (LDGE) composites suitable for absorbing minimum 80 per cent of incident microwave energy in 8 GHz to 12 GHz (X-band) is reported. LDGE composites having different densities were fabricated using a novel method of partially replacing conventional S-glass fabric with low density glass (LDG) layers as the reinforcement m...

this research investigates the effect of the post-cure time on the residual stresses in laminated composites. laminated composites were made of t300 carbon fibers and epoxy resin. the post-cure process was carried out at the constant temperature of 120 °c for 6 and 12 hours for two specimens. the slitting method was employed to determine through-thickness residual stress distribution of the com...