Prior detailed microscopic observations have revealed the essential mechanisms of damage in through-thickness reinforcing tows when a delamination crack passes. As expected, the damage sequence depends quite strongly on whether the crack is loaded in Mode I or Mode II and, if loading is mixed mode, the order of loading. Here, micromechanical models are presented that show how geometry and const...

Unidirectional (UD) prepreg based laminates, consolidated in an autoclave, have been the principal material choice for the composites industry especially for aerospace application. There are concerns, however, about the damage tolerance and compression after impact (CAI) performance of UD composites, in addition to the high manufacturing and material costs. In recent years, the composites indus...

In this work, multifilament, continuous polyacrylonitrile (PAN) fiber tow was solution spun mimicking industrial processing at the small pilot scale (0.5 k tow), while carefully altering the composition of the coagulation bath, in order to determine the effect on the resulting fiber shape, density, orientation, and tensile properties at varying points in the spinning process. Novel here are the...

The Northwest Fisheries Science Center (NWFSC) has produced reports documenting total fishing mortality for groundfish for the years 2004-2006, which are available on the NWFSC’s website (Hastie 2006, Hastie and Bellman 2006, 2007). A central element of these analyses is the estimation of discard occurring in the non-hake groundfish bottom trawl fishery. This estimation process incorporates dat...

Three-scale homogenization procedure is proposed in this paper to provide estimates of the effective thermal conductivities of porous carbon-carbon textile composites. On each scale the level of fiber tow (micro-scale), the level of yarns (meso-scale) and the level of laminate (macro-scale) a two step homogenization procedure based on the Mori-Tanaka averaging scheme is adopted. This involves e...

A multi-way control system for spun yarn breakage detecting and tow stopping is presented for linen wet spinning frame upgrade in medium-sized businesses of southeastern China. The signals from periodic rotations of spun yarns are picked by piezoelectric sensors. After input protection and multiplexers, the weak voltage signal from gated channel is processed through links including voltage foll...

Ion engines accelerate electrically charged plasma through two optic grids and emit the ions as exhaust. The process facilitates propulsion without use of chemical propellants. Braided carbon fiber reinforced composite (C(f)/C) optics are presently being considered for use as the accelerator and screen grids in ion propulsion engines. In this study the mechanical behavior of four candidate tow ...