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This paper reports on the experimental study of carbide and polycrystalline diamond (PCD) drills used for drilling composite/titanium stacks. Materials systems used in this study were multi-directional carbon fiber in an epoxy matrix and titanium 6Al-4V. The drill materials included tungsten carbide (WC; 9%Co ultra fine grain) and polycrystalline diamond (PCD; bimodal grade). Torque and thrust force were measured during the drilling experiments. Tool wear of both drills was periodically examined during the drilling tests using various microscopic techniques such as optical and Scanning Electron Microscope (SEM). Effect of tool materials and process condition on hole quality parameters such as hole diameter, surface roughness, and titanium burrs, were examined. Dissimilar mechanical and thermal properties of the stacks affected the tool life and resulted in the decreased hole quality for both cutting tool materials, although to a differing degree.

Flame spread over a melting thermally thick composite polymer is investigated in a channel flow above a condensed fuel. The condensed fuel consists of an isotropic (melted layer of) liquid near the heated surface and an anisotropic (not-yet-melted) solid surrounding it. The influence of the solid anisotropy is evaluated by changing the solid conductivity (ksx or ksy) in one particular direction (x in horizontal flame spread direction or y in vertical direction, see schematics in Figure 1) while keeping the other properties fixed. Note that the liquid conductivity kl has no isotropic behavior. Numerically, it is found that the flame spread rate decreases with either increasing ksx or ksy. The decrease with respect to ksy is less than for a comparable case described by the de Ris formula for an isotropic pure solid. The flame spread rate is more accurately determined by an analytical formula derived for spread across a melting solid fuel.

A successful prototype knowledge-based system has been developed for polymer composites design. This reporting focuses on the expansion and extension of the prototype. The expansion effort widens the scope of the system to include additional matrix and fiber constituents. Initially, the system designs a single composite material meeting the desired performance characteristics. The first extension effort involves modifications to produce a family of designs, presenting a more effective aide to composite designers. Another extension effort involves the selection of manufacturing methods for the composites produced. These improvements give rise to a design system that is approaching industrial level effectiveness.

This paper presents a study of the effects of a resin soluble thermoplastic preform binder on the Resin Transfer Molding (RTM) process. The focus of the study is the rate of dissolution of the binder in the resin and the associated viscosity changes in the resin. Tests on the rate of binder dissolution from continuous strand glass mats show that after one minute of exposure to styrene, roughly half of the medium solubility binder from Unifilo 750 will dissolve and all of the high solubility binder from Unifilo 101 will dissolve. As the concentration of binder in the resin increases from 0 to 5 wt. percent, the viscosity of a vinyl ester resin increases from 125 cps to 280 cps. The viscosity of the resin has also been monitored in continuous flow experiments through the mats placed in a rectangular plague mold, at different flowrates. In these runs, the viscosity varied from 245 mPa-s to 145 mPa-s when the fill time was 2.2 minutes.

Squeak and rattle has become a primary source of undesired noise in automobiles due to the continual diminishment of engine, power train and tire noise levels. This article presents a finite-element-based methodology for the improvement of rattle performance of vehicle components. For implementation purposes, it has been applied to study the rattle of a glove compartment latch and corner rubber bumpers. Results from the glove compartment study are summarized herein. Extensions to other rattle problems are also highlighted.